Loudspeaker and earphone

Abstract

One or more embodiments of the present description relate to a loudspeaker, comprising: a magnetic circuit assembly; a voice coil assembly, at least part of the voice coil being located in a magnetic gap of the magnetic circuit assembly; and a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm being spaced apart in a vibration direction, at least one of the first diaphragm and the second diaphragm being connected to a voice coil assembly, and the voice coil assembly being configured to drive the first diaphragm and the second diaphragm to synchronously vibrate in the same direction. The voice coil assembly comprises a first voice coil and a second voice coil arranged in the vibration direction, the first diaphragm is connected to the first voice coil, the second diaphragm is connected to the second voice coil, the first voice coil and the second voice coil are connected via a connector, and the first voice coil and the second voice coil respectively drive the first diaphragm and the second diaphragm to synchronously vibrate in the same direction. By means of the cooperation between the magnetic circuit assembly and the voice coil assembly, and by means of connecting the two voice coils via the connector, it can be better ensured that the first diaphragm and the second diaphragm synchronously vibrate in the same direction, thereby improving the output effect of an earphone.

Description

A speaker and headphones Cross-references

[0001] This specification claims priority to Chinese application No. 202410966001.5 filed on July 17, 2024, and Chinese application No. 202520976939.5 filed on May 16, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This specification relates to the field of acoustic technology, and in particular to a loudspeaker and headphones. Background Technology

[0003] As people's living standards continue to improve, consumers are also demanding more from headphones. In addition to stable output performance, they also need to be able to block out ambient noise in noisy or even high-noise environments for normal listening. Therefore, the noise cancellation performance of headphones has a great impact on user comfort.

[0004] Therefore, it is necessary to propose a speaker and headphones to improve the noise reduction effect of acoustic devices. Summary of the Invention

[0005] This specification provides a loudspeaker, including: a magnetic circuit assembly; a voice coil assembly, at least a portion of which is located within a magnetic gap in the magnetic circuit assembly; a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm being spaced apart in a vibration direction; at least one of the first diaphragm and the second diaphragm being connected to the voice coil assembly, the voice coil assembly being configured to drive the first diaphragm and the second diaphragm to vibrate synchronously in the same direction; wherein, the voice coil assembly includes a first voice coil and a second voice coil disposed along the vibration direction, the first diaphragm being connected to the first voice coil, the second diaphragm being connected to the second voice coil, the first voice coil and the second voice coil being connected by a third connector, and the first voice coil and the second voice coil respectively driving the first diaphragm and the second diaphragm to vibrate synchronously in the same direction.

[0006] This specification also provides an earphone, including a speaker as described above. The earphone further includes: a first housing, with the speaker disposed within the first housing; in a wearing state, the first housing includes an inner sidewall facing the external auditory canal and an outer sidewall opposite to the inner sidewall and away from the external auditory canal, the inner sidewall having a first sound outlet hole and the outer sidewall having a second sound outlet hole; the first diaphragm of the speaker and the inner sidewall form a first acoustic cavity communicating with the first sound outlet hole, and the second diaphragm of the speaker and the outer sidewall form a second acoustic cavity communicating with the second sound outlet hole. Attached Figure Description

[0007] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0008] Figure 1 is a schematic diagram of the physiological structure of an exemplary ear provided in some embodiments of this application;

[0009] Figure 2 is a schematic diagram of the wearing state of the headphones when they are worn in the ear, according to some embodiments of this specification;

[0010] Figure 3 is a schematic diagram of an exemplary module of a sound-generating part according to some embodiments of this specification;

[0011] Figure 4 is a schematic diagram of the internal structure of the sound-generating part according to some embodiments of this specification;

[0012] Figure 5 shows the frequency response curves of headphones with different diaphragms according to some embodiments of this specification;

[0013] Figure 6 is a schematic diagram of the diaphragm assembly according to some embodiments of this specification;

[0014] Figure 7 is a magnified schematic diagram of a partial structure of the diaphragm assembly in Figure 6;

[0015] Figure 8 is a dimensional schematic diagram of the structure shown in Figure 7;

[0016] Figure 9 is a schematic diagram of the driving force coefficient of a loudspeaker corresponding to different voice coil assembly movement distances according to some embodiments of this specification;

[0017] Figure 10 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different first ratios according to some embodiments of this specification;

[0018] Figure 11 is another dimensional schematic diagram of the structure shown in Figure 7;

[0019] Figure 12 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different second ratios according to some embodiments of this specification;

[0020] Figure 13 is another dimensional schematic diagram of the structure shown in Figure 7;

[0021] Figure 14 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different third ratios according to some embodiments of this specification;

[0022] Figure 15 is another dimensional schematic diagram of the structure shown in Figure 7;

[0023] Figure 16 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different fourth ratios according to some embodiments of this specification;

[0024] Figure 17 is another dimensional schematic diagram of the structure shown in Figure 7;

[0025] Figure 18 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different fifth ratios according to some embodiments of this specification;

[0026] Figure 19 is a schematic diagram of the structure of the in-line sticker according to some embodiments of this specification;

[0027] Figure 20 is a schematic cross-sectional view of the sound-generating part in the short axis direction according to some embodiments of this specification;

[0028] Figure 21 is an exploded structural diagram of a sound-generating part according to some embodiments of this specification;

[0029] Figure 22 is a schematic diagram of the structure of the sound-generating component in the sound-generating part according to some embodiments of this specification;

[0030] Figure 23 is an exploded structural diagram of a sound-generating component according to some embodiments of this specification;

[0031] Figure 24 is a schematic cross-sectional view of a sound-generating component according to some embodiments of this specification;

[0032] Figure 25 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different sizes of sound outlets according to some embodiments of this specification;

[0033] Figures 26A-26C are schematic diagrams showing different positions of the sound outlet according to some embodiments of this specification;

[0034] Figure 27 is a schematic diagram of the frequency response curves of a loudspeaker corresponding to a sound outlet at different positions, as shown in some embodiments of this specification.

[0035] Figures 28A and 28B are schematic diagrams showing different relative positions of the first and second sound outlets according to some embodiments of this specification;

[0036] Figure 29 is a schematic diagram of the frequency response curves of the loudspeakers corresponding to the first and second sound holes set at different positions according to some embodiments of this specification.

[0037] Figure 30 is a schematic diagram of first and second sound holes of different sizes according to some embodiments of this specification;

[0038] Figure 31 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different sizes of first and second sound holes according to some embodiments of this specification.

[0039] Figures 32A and 32B are schematic diagrams of acoustic apertures of different shapes according to some embodiments of this specification;

[0040] Figure 33 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different shapes of acoustic holes according to some embodiments of this specification;

[0041] Figures 34A-34B are schematic diagrams showing different numbers of acoustic holes according to some embodiments of this specification;

[0042] Figure 35 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different opening shapes and different numbers of acoustic holes according to some embodiments of this specification;

[0043] Figures 36A-36F are schematic diagrams of sound outlet holes with different distributions of non-single concentrated openings according to some embodiments of this application;

[0044] Figure 37 is a schematic diagram of the frequency response curves of the sound-emitting part corresponding to the sound-emitting part with different distributions of non-single concentrated openings shown in some embodiments according to this description.

[0045] Figure 38 is a schematic diagram showing the relative positions of the first sound outlet and the tuning hole according to some embodiments of this specification;

[0046] Figure 39 is a schematic diagram of the frequency response curves of the sound-emitting part corresponding to different distances between any two holes or between any hole and the boundary of the acoustic cavity in Figure 38.

[0047] Figure 40 is a schematic diagram of the frequency response curves of the sound-emitting part corresponding to the first sound outlet and the tuning hole in Figure 38 when the area ratios are different.

[0048] Figure 41 is a schematic diagram of the internal structure of a loudspeaker according to some embodiments of this specification;

[0049] Figure 42 is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification;

[0050] Figure 43A is an exploded schematic diagram of a loudspeaker according to some embodiments of this specification;

[0051] Figure 43B is another exploded view of a loudspeaker according to some embodiments of this specification;

[0052] Figures 44A-46B are schematic diagrams of different structures of a loudspeaker according to some embodiments of this specification;

[0053] Figure 47 is a schematic diagram of the driving force coefficients of loudspeakers including internal magnets of different sizes according to some embodiments of this specification;

[0054] Figure 48 is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification;

[0055] Figure 49 is another exemplary internal structure diagram of a loudspeaker according to some embodiments of this specification;

[0056] Figure 50 is a schematic diagram of the internal structure of the loudspeaker shown in Figure 49 from another perspective;

[0057] Figure 51 is a schematic diagram of the explosion of the loudspeaker shown in Figure 49;

[0058] Figure 52 is a schematic diagram of the driving force coefficients of loudspeakers corresponding to through holes of different sizes according to some embodiments of this specification;

[0059] Figure 53 is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification;

[0060] Figure 54A is another exemplary structural schematic diagram of a loudspeaker according to some embodiments of this specification;

[0061] Figure 54B is a structural schematic diagram of the loudspeaker shown in Figure 54A from another perspective;

[0062] Figure 55 is a schematic diagram of another connection structure between the first voice coil and the second voice coil according to some embodiments of this specification;

[0063] Figure 56 is another exemplary structural schematic diagram of a loudspeaker according to some embodiments of this specification;

[0064] Figure 57 is a schematic diagram of a skeleton according to some embodiments of this specification;

[0065] Figure 58 is another schematic diagram of the skeleton shown according to some embodiments of this specification;

[0066] Figure 59 is a schematic diagram of the frequency response curve of the loudspeaker shown in Figure 58;

[0067] Figure 60 is a schematic diagram of the structure of a magnetic shield according to some embodiments of this specification;

[0068] Figures 61A-61G are schematic diagrams of different exemplary structures of a loudspeaker according to some embodiments of this specification;

[0069] Figure 62 is a schematic diagram of the frequency response curves of a loudspeaker corresponding to different sizes of inner and outer magnets according to some embodiments of this specification;

[0070] Figure 63 is another structural schematic diagram of a loudspeaker according to some embodiments of this specification;

[0071] Figures 64A and 64B are schematic diagrams of the frequency response curves of loudspeakers corresponding to magnets of different sizes and magnetic shields in Figure 63;

[0072] Figure 65 is another cross-sectional structural schematic diagram of a sound-generating component according to some embodiments of this specification;

[0073] Figure 66 is an exploded structural diagram of a loudspeaker according to some embodiments of this specification;

[0074] Figure 67A is another exploded view of a loudspeaker according to some embodiments of this specification;

[0075] Figure 67B is a cross-sectional view of the loudspeaker shown in Figure 67A in the width direction;

[0076] Figure 67C is a cross-sectional view of the loudspeaker shown in Figure 67A along its length.

[0077] Figure 68A is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification;

[0078] Figure 68B is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification;

[0079] Figure 69A is a schematic diagram of a loudspeaker including a magnetic circuit fixing ring according to some embodiments of this specification;

[0080] Figure 69B is a structural schematic diagram of the loudspeaker shown in Figure 69A from another perspective;

[0081] Figure 70A is another structural schematic diagram of a loudspeaker including a magnetic circuit fixing ring, according to some embodiments of this specification;

[0082] Figure 70B is a structural schematic diagram of the loudspeaker shown in Figure 70A from another perspective. Detailed Implementation

[0083] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0084] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0085] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0086] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0087] Figure 1 is a schematic diagram of the physiological structure of an exemplary ear provided in some embodiments of this application. Referring to Figure 1, the exemplary ear may include physiological parts such as the external auditory canal 11, the concha cavity 12, the cymba conchae 13, the triangular fossa 14, the antihelix 15, the scaphoid fossa 16, the helix 17, the earlobe 18, and the crus of the helix 19. Although the external auditory canal 11 has a certain depth and extends to the tympanic membrane of the ear, unless otherwise specified, the external auditory canal 11 can be understood as its entrance away from the tympanic membrane (i.e., the ear hole or ear canal opening). Furthermore, the physiological parts such as the concha cavity 12, the cymba conchae 13, and the triangular fossa 14 have a certain volume and depth in three-dimensional space, and the concha cavity 12 is directly connected to the external auditory canal 11, that is, it can be simply regarded as the aforementioned ear hole being located at the bottom of the concha cavity 12.

[0088] Since the external auditory canal 11, concha 12, cymba conchae 13, triangular fossa 14 and other physiological parts have a certain depth and volume in three-dimensional space, the headphones provided in some embodiments of this specification can achieve stable wearing of the headphones by means of one or more physiological parts of the ear.

[0089] For example, the earphone can be worn by using other parts of the ear besides the external auditory canal 11 (such as the cymba conchae 13, triangular fossa 14, antihelix 15, scaphoid 16, helix 17, etc. or combinations thereof); for example, when worn, the entire or part of the earphone structure can contact the upper part of the external auditory canal 11 (such as one or more physiological parts such as the cymba conchae 13, triangular fossa 14, antihelix 15, scaphoid 16, helix 17, crus of helix 19, etc.); or, when worn, the entire or part of the earphone structure can be located in the first region P1 enclosed by the dotted line in Figure 1, which at least includes the cymba conchae 13 and triangular fossa 14, or in the second region P2 enclosed by the dotted line in Figure 1, which at least includes the conchae cavity 12, or in the front side of the crus of helix 19 (i.e., in the third region P3 enclosed by the dotted line in Figure 1).

[0090] By utilizing parts of the ear other than the external auditory canal 11, the headphones can be worn and sound can be transmitted. This not only "liberates the external auditory canal," reducing the impact of headphones on the user's ear health, but also effectively improves the user experience. For example, when a user wears headphones on the road, the headphones will not block the external auditory canal 11, allowing the user to receive both sound from the headphones and ambient sounds (such as horns, car bells, surrounding voices, traffic signals, etc.), thereby effectively reducing the occurrence of traffic accidents.

[0091] Due to individual differences among users, ears may vary in shape, size, and other dimensions. To facilitate description and understanding, and to minimize or even eliminate these individual differences, unless otherwise specified, this application primarily uses an ear model with a "standard" shape and size as a reference to describe the structure of the headphones in different embodiments and how they are worn on that ear model. For example, a simulator (such as GRAS 45BC KEMAR) containing a head and its (left and right) ears can be manufactured based on ANSI:S3.36, S3.25, and IEC:60318-7 standards as a reference for wearing headphones, thus representing the scenario of most users normally wearing headphones.

[0092] Therefore, descriptions such as "user wearing," "in wearing state," and "under wearing state" in this application can refer to the headphones described in this application being worn on the ears of the aforementioned simulator. Of course, considering the individual differences among different users, the structure, shape, size, thickness, etc. of one or more parts of the ear can be differentiated according to different ear shapes and sizes. These differentiated designs can be manifested in the characteristic parameters of one or more parts of the headphones having different ranges of values ​​to adapt to different ears.

[0093] It should be noted that in medicine, anatomy, and other fields, the human body can be defined by three basic planes: the sagittal plane, the coronal plane, and the horizontal plane; and three basic axes: the sagittal axis, the coronal axis, and the vertical axis. The sagittal plane is a section perpendicular to the ground along the anteroposterior direction of the body, dividing the body into left and right parts. The coronal plane is a section perpendicular to the ground along the left-right direction of the body, dividing the body into anterior and posterior parts. The horizontal plane is a section parallel to the ground along the vertical direction of the body, dividing the body into superior and inferior parts. Correspondingly, the sagittal axis is the axis along the anteroposterior direction of the body and perpendicular to the coronal plane; the coronal axis is the axis along the left-right direction of the body and perpendicular to the sagittal plane; and the vertical axis is the axis along the vertical direction of the body and perpendicular to the horizontal plane.

[0094] Furthermore, the "front side of the ear" mentioned in this application is a concept relative to "back side of the ear." The former refers to the side of the ear that is away from the head, while the latter refers to the side of the ear that faces the head; both refer to the user's ear. Specifically, observing the ear of the simulator along the direction of the human coronal axis yields the schematic diagram of the front side of the ear shown in Figure 1.

[0095] It should be noted that the above description of the ear is for illustrative purposes only and is not intended to limit the scope of this application. Those skilled in the art can make various changes and modifications based on the description in this application (for example, the structure of the earphone can partially or completely cover the external auditory canal 11), and these changes and modifications are still within the protection scope of this application.

[0096] As people's demands for quality of life continue to rise, consumers are also placing higher requirements on headphones. Besides stable output performance, they also need to be able to block out ambient noise for normal listening in noisy or even high-noise environments. For in-ear headphones, the sound outlet is located inside the user's ear canal, resulting in a louder sound. Simultaneously, some ambient noise is blocked outside the ear canal. In this case, the headphone's noise-canceling technology actively cancels out the ambient noise entering the ear canal. For open-back headphones, which do not fit inside the ear canal, the sound output is some distance from the ear canal and cannot form a closed sound transmission channel. More ambient noise enters the ear canal, significantly impacting the user's listening experience. Furthermore, the open structure and distance between the sound outlet and the ear canal opening of open-back headphones can also cause sound leakage into the surrounding environment, resulting in noticeable sound leakage. To improve the user experience of open-back headphones, such as enhancing active noise cancellation, sound output, and sound leakage reduction, it is necessary to balance miniaturization and lightweight design while providing higher output intensity, lower distortion, more stable amplitude and phase frequency response with less fluctuation, and flatter output across a wider frequency range to deliver higher sound output and / or meet the requirements for better noise cancellation.

[0097] This specification provides a pair of headphones that, in the context of open-back headphones, improve the headphone's sound production efficiency, reduce distortion, and enable the headphone to have a flatter output over a wider frequency range, thereby enhancing sound output, reducing sound leakage, and / or active noise cancellation.

[0098] Figure 2 is a schematic diagram of the wearing state of the headphones when worn on the ear according to some embodiments of this specification, and Figure 3 is a schematic diagram of an exemplary module of the sound-generating part according to some embodiments of this specification.

[0099] Please refer to Figures 2 and 3. Some embodiments of this specification provide an open-back headphone (hereinafter referred to as the headphone), including a sound-emitting part 100 and an ear hook. The ear hook is configured to place the sound-emitting part 100 near the ear but without blocking the external auditory canal 11. It should be noted that due to individual differences among users, when the headphone is worn by different users, the sound-emitting part 100 may partially cover the external auditory canal 11, but the external auditory canal 11 will still not be blocked. This will be explained in detail below.

[0100] The sound-emitting part 100 includes a first housing 110, a sound-emitting component, and a microphone component 140, etc. The sound-emitting component is disposed inside the first housing 110 and may include a speaker 120. The speaker 120 can convert electrical signals into corresponding mechanical vibrations, thereby generating sound output (e.g., noise-canceling sound, audio played through headphones, etc.). For example, the sound generated by the speaker 120 may include noise-canceling sound. The noise-canceling sound output to the outside of the first housing 110 may have the same amplitude and opposite phase to the ambient noise near the external auditory canal 11, so as to eliminate the ambient noise near the external auditory canal 11 and achieve active noise cancellation. The sound generated by the speaker 120 may also include other sounds such as call sounds, played audio, and reminder sounds. After these sounds are output to the outside of the first housing 110, they can be guided to the external auditory canal 11 to ensure the user's listening effect.

[0101] In some embodiments, the sound-generating assembly further includes a limiting component 130, which is used to position and confine the speaker 120 inside the first housing 110. On the one hand, by fixing the speaker 120 inside the first housing 110 by the limiting component 130, it can be ensured that the sound generated by the speaker 120 is stably output to the outside of the first housing 110 through the acoustic holes provided in the first housing 110; on the other hand, by limiting the speaker 120 by the limiting component 130, it can be prevented that the speaker 120 shakes relative to the first housing 110 when vibrating, thereby ensuring the sound output performance of the sound-generating part 100.

[0102] The microphone assembly 140 can be used to collect sound signals, such as user voice and ambient sounds. For example, based on the ambient noise collected by the microphone assembly 140, the output of the speaker 120 can be adjusted so that the sound output by the speaker 120 includes a sound signal that cancels out the ambient noise, thereby achieving active noise cancellation of the headphones against ambient noise.

[0103] In some embodiments, the ear hook may include an ear hook housing and a battery assembly, a circuit board assembly, etc. disposed inside the ear hook housing. The battery assembly, speaker 120, and microphone assembly are structurally electrically connected to the circuit board assembly. The circuit board assembly can be understood as a collection of the headphone's main control board or motherboard and related components. The circuit board assembly plays a role in regulating and managing all or some of the functional components in the headphone; for example, it is used in the headphone to convert and process electrical signals to support the realization of various headphone functions (such as supporting the headphone to turn on and off, switch playback content, increase or decrease volume, etc.).

[0104] Referring to Figure 2, in some embodiments, the ear hook can be divided into two parts along its length: a battery section 200 and an adapter section 300. The adapter section 300 connects the battery section 200 and the sound-generating section 100. In the wearing state, a portion of the battery section 200 (e.g., the portion occupied by the battery assembly and circuit board assembly) hangs between the auricle and the head, while the other portion of the battery section 200 extends towards the side of the auricle away from the head and connects to the adapter section 300. The sound-generating section 100 is worn near the external auditory canal 11 without obstructing it, thus making the earphone an open-back design. Furthermore, the battery assembly and circuit board assembly can be disposed in the battery section 200, and the adapter section 300 can include earphone buttons and an adapter plate for electrically connecting the circuit board assembly to the speaker 120 and microphone assembly 140. In some embodiments, the battery assembly and circuit board assembly can be disposed at the end of the battery section 200 away from the adapter section 300 to balance the center of the earphone and improve wearing comfort.

[0105] In some embodiments, to improve the stability of the headphones while worn, the headphones may employ any one or a combination of the following methods: First, at least a portion of the ear hook is configured as a conformal structure (e.g., an arc-shaped hook) that conforms to at least one of the back of the ear and the head, thereby increasing the contact area between the ear hook and the ear or head, and thus increasing the resistance to the headphones falling off the ear. Second, at least a portion of the ear hook is configured as an elastic structure, such that the ear hook has a certain elastic deformation while worn, thereby increasing the pressure of the ear hook on the ear or head, and thus increasing the resistance to the headphones falling off the ear. Third, at least a portion of the ear hook is configured to rest against the head while worn, such that the ear hook forms a reaction force pressing against the ear, causing the sound-emitting part 100 to press against the front of the ear, thereby increasing the resistance to the headphones falling off the ear. Fourth, the sound-emitting part 100 and the ear hook are configured to clamp the physiological parts of the ear, such as the area where the helix 17 and the area where the concha 12 are located, respectively, from the front and back sides of the ear when worn, thereby increasing the resistance to the earphone falling off the ear. Fifth, the sound-emitting part 100 is configured to extend at least partially into the physiological parts of the ear, such as the concha 12, cymba concha 13, triangular fossa 14, and scaphoid 16, when worn, thereby increasing the resistance to the earphone falling off the ear.

[0106] In some embodiments, the headphones can be combined with products such as glasses, headphones, head-mounted displays, AR / VR helmets, etc.; for example, the ear hooks may be omitted or retained, and the sound-emitting part 100 may be worn near the user's ears by means of suspension, clamping, etc.

[0107] Figure 4 is a schematic diagram of the internal structure of the sound-generating part according to some embodiments of this specification.

[0108] Referring to Figure 2, the sound-emitting part 100 may have a major axis direction and a minor axis direction that are perpendicular to the thickness direction and orthogonal to each other. The major axis direction can be defined as the direction with the maximum extension dimension in the shape of the two-dimensional projection surface of the sound-emitting part 100 (e.g., the projection of the sound-emitting part 100 onto the plane containing its outer surface or onto the sagittal plane). (For example, when the projection shape is rectangular or approximately rectangular, the major axis direction is the length direction of the rectangle or approximately rectangular.) The minor axis direction can be defined as the direction perpendicular to the major axis direction in the shape of the projection of the sound-emitting part 100 onto the sagittal plane (e.g., when the projection shape is rectangular or approximately rectangular, the minor axis direction is the width direction of the rectangle or approximately rectangular.) The thickness direction can be defined as the direction perpendicular to the two-dimensional projection surface; for example, the thickness direction coincides with the direction of the coronal axis, both pointing towards the left and right sides of the body. In some embodiments, the thickness direction can also be defined as the direction in which the shell approaches or moves away from the ear when worn. In some embodiments, when the sound-emitting part 100 is tilted while in the wearing state, the major axis direction and the minor axis direction are still parallel or approximately parallel to the sagittal plane. The major axis direction may have a certain angle with the direction of the sagittal axis, that is, the major axis direction is also tilted accordingly. The minor axis direction may have a certain angle with the direction of the vertical axis, that is, the minor axis direction is also tilted. In some embodiments, the entire or part of the structure of the housing of the sound-emitting part 100 can extend into the concha cavity 12, that is, the projection of the housing of the sound-emitting part 100 on the sagittal plane overlaps with the projection of the concha cavity 12 on the sagittal plane. In some embodiments, the major axis direction and the minor axis direction of the speaker 120 are consistent with the major axis direction and the minor axis direction of the sound-emitting part 100.

[0109] Referring to Figures 2 and 4, in some embodiments, the first housing 110 of the sound-emitting part 100 may include multiple different housing walls such as an inner sidewall 110a, an outer sidewall 110b, an upper sidewall 110c, a lower sidewall 110d, and a front sidewall 110e. Specifically, the inner sidewall 110a is the housing sidewall of the first housing 110 facing the ear (e.g., the external auditory canal 11) in the thickness direction when worn; the outer sidewall 110b is the housing sidewall of the first housing facing away from the ear (e.g., the external auditory canal 11) in the thickness direction when worn; the upper sidewall 110c is the housing sidewall of the first housing close to the top of the head in the short axis direction when worn; the lower sidewall 110d is the housing sidewall of the first housing 110 away from the top of the head in the short axis direction when worn; and the front sidewall 110e is the housing sidewall of the first housing 110 facing behind the ear in the long axis direction when worn. It is understandable that these multiple different shell walls can together form a cavity for the sound-emitting part 100, and the sound-emitting components (such as the loudspeaker 120) are housed within the cavity.

[0110] Referring to Figure 4, in some embodiments, inside the first housing 110, a first acoustic cavity 111-1 is formed between the speaker 120 and one of the side walls of the first housing 110, and a second acoustic cavity 111-2 is formed between the speaker 120 and the opposite side wall. The one side wall is provided with a first sound outlet 112-1 that acoustically communicates with the speaker 120 through the first acoustic cavity, and the opposite side wall is provided with a second sound outlet 112-2 that acoustically communicates with the speaker 120 through the second acoustic cavity. The sound-emitting part 100 will be described below using the example of the speaker 120 forming a first acoustic cavity 111-1 with the inner side wall, the speaker 120 forming a second acoustic cavity 111-2 with the outer side wall, the inner side wall having a first sound outlet 112-1, and the outer side wall having a second sound outlet 112-2.

[0111] In some embodiments, when worn, at least a portion of the first housing 110 may be located within the concha 12, with its inner wall cooperating with the concha 12 to form an auxiliary cavity communicating with the external auditory canal 11. This auxiliary cavity is typically semi-open, and the first sound outlet 112-1 is located within the auxiliary cavity. Thus, the sound output through the first sound outlet 112-1 can be focused by the auxiliary cavity, with most of the sound propagating into the external auditory canal 11. The small portion of sound propagating outside the external auditory canal 11 (e.g., noise-canceling sounds) can be counteracted by ambient noise near the external auditory canal 11, thereby improving listening performance, enhancing active noise cancellation, and reducing sound leakage.

[0112] To effectively enhance the active noise cancellation performance of headphones in open-back applications, the headphones can be designed to have a relatively flat output over a wide frequency range. In some embodiments, the frequency response curve of the sound output from the headphones to the outside of the first housing 110 has a first resonant peak and a second resonant peak, where the peak resonant frequency of the first resonant peak is lower than that of the second resonant peak. In some embodiments, the headphones primarily output through a sound outlet (e.g., a first acoustic hole located on the inner sidewall of the first housing), and the headphone output can be measured by a test microphone located 2 mm from the sound outlet. In some embodiments, the first resonant peak and the second resonant peak refer to two consecutive resonant peaks adjacent to each other on the frequency response curve, with a flat region between these two resonant peaks. In some embodiments, the first resonant peak may be generated by the hardware structure in the sound-emitting part 100, and its peak resonant frequency is mainly affected by the acoustic components in the speaker 120, such as the diaphragm, magnetic circuit assembly, and voice coil assembly. In some embodiments, as the frequency gradually increases, the frequency response curve output from the first sound outlet 112-1 may have multiple rising segments, and the first resonant peak may refer to the first of these rising segments. For example, the peak resonant frequency of the first resonant peak can be set to no more than 300Hz. A first Helmholtz resonant cavity model can be formed by utilizing the connection between the first acoustic cavity 111-1 and the first sound outlet 112-1, and a second Helmholtz resonant cavity model can be formed by utilizing the second acoustic cavity 111-2 and the second sound outlet 112-2. The first and second sound outlets 112-1 and 112-2 serve as the necks of their respective Helmholtz resonant cavity models. The second resonant peak can be generated by the first Helmholtz resonant cavity model, and the peak resonant frequency of the second resonant peak is approximately equal to the resonant frequency of the first Helmholtz resonant cavity model. A relatively stable flat region with a high sound pressure level can be formed between the first and second resonant peaks, and the peak sound pressure level of the second resonant peak is higher than that of the flat region. In some embodiments, the peak sound pressure level of the second resonant peak can be more than 2 dB higher than the sound pressure level of the flat region (the test conditions can be set based on IEC 60268-7, for example, in a free field, using a 1 / 2-inch standard microphone, and the microphone is 2 mm away from the headphone output hole).

[0113] Specifically, the headphones exhibit high active noise cancellation performance within the frequency range corresponding to the flat region between the first and second resonant peaks. Designing the first and second resonant peaks can influence the frequency range of the headphones' active noise cancellation; designing the flat region (e.g., its flatness, curve height, etc.) can affect the effectiveness of active noise cancellation. For example, the flatness of the region reflects the stability of the headphone's output sound; the more stable the output, the easier it is to perform active noise cancellation, resulting in better performance. Similarly, the curve height of the flat region reflects the volume of sound the headphones can output; the louder the sound output, the greater the noise the headphones can cancel, leading to better active noise cancellation.

[0114] To design the first resonant peak, the second resonant peak, and the flat region between them, in some embodiments, the loudspeaker 120 may include a magnetic circuit assembly 122, a voice coil assembly 123, and a first diaphragm 121-1 and a second diaphragm 121-2. The voice coil assembly 123 drives the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction. At least a portion of the voice coil assembly 123 is located within the magnetic gap of the magnetic circuit assembly 122. The first diaphragm 121-1 and the second diaphragm 121-2 are spaced apart in the vibration direction, and at least one of the first diaphragm 121-1 and the second diaphragm 121-2 is connected to the voice coil assembly 123. The voice coil assembly 123 is configured to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction. The first diaphragm 121-1 and the inner wall of the first housing 110 are spaced apart and opposite each other in the vibration direction (i.e., the thickness direction) to form a first acoustic cavity 111-1. The second diaphragm 121-2 and the outer wall of the first housing 110 are spaced apart and opposite each other in the vibration direction to form a second acoustic cavity 111-2. The first diaphragm 121-1 and the second diaphragm 121-2 form a common cavity 111-3.

[0115] It should be noted that the synchronous and co-directional vibration of the first diaphragm 121-1 and the second diaphragm 121-2 means that the first diaphragm 121-1 and the second diaphragm 121-2 vibrate in the same direction and with the same amplitude at any given time. Specifically, "co-directional" means that the vibration directions of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent; "synchronous" means that the vibration states of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent in time, that is, the vibration phases of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent. Due to the influence of various factors such as manufacturing processes, it is difficult for the vibration phases of the first diaphragm 121-1 and the second diaphragm 121-2 to achieve perfect consistency under ideal conditions. Therefore, the "consistent vibration phase" described in this application can mean that, at least within the acoustic frequency range between the first and second resonant peaks, the phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 at different frequencies is always less than 35°. For example, the test conditions for the phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 can be set based on IEC 60268-7. For instance, in a free field, a 1 / 2-inch standard microphone can be placed near the first sound outlet 112-1 and another 1 / 2-inch standard microphone can be placed near the second sound outlet 112-2. The phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 can be determined based on the sound signals collected by the two standard microphones.

[0116] The connection configuration between the first acoustic cavity 111-1 and the first sound outlet 112-1 can be approximately equivalent to a first Helmholtz resonator model, and the connection configuration between the second acoustic cavity 111-2 and the second sound outlet 112-2 can be approximately equivalent to a second Helmholtz resonator model. The first sound outlet 112-1 and the second sound outlet 112-2 serve as the neck openings of their respective Helmholtz resonator models. When the speaker 120 vibrates and outputs sound, the first sound outlet 112-1 outputs a first sound, and the second sound outlet 112-2 outputs a second sound. The superposition of the first and second sounds constitutes the sound output by the headphones.

[0117] The first resonant peak and the flexibility of the first diaphragm 121-1 and the second diaphragm 121-2 in the vibration direction are related. The second resonant peak is related to the first acoustic cavity 111-1 and the second acoustic cavity 111-2. The flat region is related to the vibration of the first diaphragm 121-1 and the second diaphragm 121-2. Specifically, the flexibility of the first diaphragm 121-1 and the second diaphragm 121-2 in the vibration direction corresponds to their elastic coefficient K along the vibration direction. Under constant load, the smaller the value of K, the lower the frequency of the first resonant peak. The magnitude of the second resonant peak corresponds to the resonant frequency of the first Helmholtz resonant cavity model (second Helmholtz resonant cavity model), which depends on the configuration of the first acoustic cavity 111-1 (second acoustic cavity 111-2) and the first sound outlet 112-1 (second sound outlet 112-2). The flatness of the flat region is related to the vibration consistency of the first diaphragm 121-1 and the second diaphragm 121-2, and the curve height of the flat region is related to the driving force of the first diaphragm 121-1 and the second diaphragm 121-2. In some embodiments, in order to improve the sound output effect and / or active noise cancellation effect of the headphones over a wider frequency range, the resonant frequencies of the first and second resonant peaks can be designed to increase the width of the flat region of the frequency response curve of the headphone output sound. For example, the first diaphragm 121-1 and the second diaphragm 121-2 can be designed (e.g., materials, structure) to reduce the resonant frequency of the first resonant peak. As another example, the first acoustic cavity 111-1 and the second acoustic cavity 111-2 can be designed to increase the resonant frequency of the second resonant peak. In some embodiments, the configuration of the first diaphragm 121-1 and the second diaphragm 121-2 can be designed to improve the vibration consistency and driving force of the first diaphragm 121-1 and the second diaphragm 121-2, reduce vibration modes, increase output, and improve the flatness and height of the frequency response curve in the flat region between the first resonant peak and the second resonant peak. Further description of the diaphragm, acoustic cavity, sound outlet, etc., is provided below in this specification.

[0118] In some embodiments, the peak resonant frequency of the second resonant peak is greater than or equal to 3 times the peak resonant frequency of the first resonant peak, thereby effectively increasing the width of the flat region of the frequency response curve of the sound output by the speaker 120, providing support for active noise cancellation in the headphones over a wider frequency range, and improving the output effect of the headphones.

[0119] In some embodiments, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak can be set to not less than 13, to further increase the width of the flat region of the frequency response curve of the headphone output sound, enabling the headphones to perform active noise cancellation over a wider frequency range and improving the headphone's sound output performance. Furthermore, in some embodiments, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak can be set to not less than 20, so that the headphone output sound has a flatter frequency response curve and a phase curve with smaller variation amplitude over a wider frequency range, further enhancing the headphone's active noise cancellation effect and improving the headphone's sound output performance.

[0120] In some embodiments, the peak resonant frequency of the first resonant peak can be set to no more than 300 Hz; the peak resonant frequency of the second resonant peak can be set to no less than 1 kHz, for example, no less than 3.65 kHz, no less than 4.5 kHz, no less than 5.8 kHz, no less than 6.7 kHz, no less than 7.5 kHz, no less than 7.75 kHz, no less than 8.75 kHz, no less than 9.25 kHz, and no less than 9.5 kHz. By designing the positions of the first and second resonant peaks, the sound output by the headphones (specifically, the sound output through the first sound outlet 112-1) can ultimately have a flat frequency response curve and a phase curve with small variation amplitude over a wider frequency range. This is beneficial for the headphones to achieve active noise cancellation over a wider frequency range and also allows the headphones to have a flatter output over a wider frequency range.

[0121] In some embodiments, the design of the first diaphragm 121-1 and the second diaphragm 121-2 is such that they are designed to be relatively "soft," i.e., with a small K value, thereby shifting the first resonant peak as low as possible. However, a small K value for the first diaphragm 121-1 and the second diaphragm 121-2 may result in multiple modes appearing radially during vibration, affecting the vibration stability of the first diaphragm 121-1 and the second diaphragm 121-2 and the flatness of the flat region. Through special structural design (e.g., the "connector" described elsewhere in this specification), it can be ensured that the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously and in the same direction, improving the vibration stability and vibration consistency of the first diaphragm 121-1 and the second diaphragm 121-2. At this point, even though the first diaphragm 121-1 and the second diaphragm 121-2 are designed to be relatively "flexible," i.e., with a smaller K-value, the speaker can still maintain high stability. Through the design of the sound outlet and acoustic cavity, the second resonant peak can be shifted as far as possible towards the higher frequencies. A lower-frequency first resonant peak and a higher-frequency second resonant peak help to widen the flat area of ​​the headphone's output frequency response curve, thereby improving the headphone's sound quality over a wider frequency range and providing support for active noise cancellation over a wider frequency range.

[0122] In some embodiments, the output of headphones (specifically, the first sound outlet 112-1) can be optimized by designing the number, shape, size, and position of the loudspeaker 120 (e.g., magnetic circuit, voice coil, diaphragm, and their structural relationships) and one or more acoustic structures (e.g., sound outlet, acoustic cavity).

[0123] In some embodiments, the first diaphragm 121-1 and the second diaphragm 121-2 can be designed to reduce the K value of the first diaphragm 121-1 and the second diaphragm 121-2, thereby shifting the first resonant peak as low as possible, increasing the width of the flat region of the frequency response curve of the headphone output sound, thereby improving the sound effect of the headphone in a wider frequency range, and also providing support for active noise cancellation of the headphone in a wider frequency range.

[0124] In some embodiments, to enhance the low-frequency output of the speaker 120 and thus improve the active noise cancellation effect of the headphones against low-frequency ambient noise, the first resonant peak of the speaker 120 in the low-frequency range (e.g., 100Hz-300Hz) is adjusted. By designing the material and thickness of the diaphragms (e.g., the first diaphragm 121-1 and the second diaphragm 121-2), the K-value of the diaphragms (e.g., the first diaphragm 121-1 and the second diaphragm 121-2) can be reduced, thereby adjusting the first resonant frequency of the speaker 120. In some embodiments, to reduce the K-value of the diaphragms (e.g., the first diaphragm 121-1 and the second diaphragm 121-2), the material of the diaphragms (e.g., the first diaphragm 121-1 and the second diaphragm 121-2) can be PU (polyurethane) or liquid silicone.

[0125] Figure 5 shows the frequency response curves of headphones with different diaphragms according to some embodiments of this specification. Curve L401 represents the frequency response of the headphones with a PU diaphragm of 0.35mm thickness; curve L402 represents the frequency response of the headphones with a PU diaphragm of 0.45mm thickness; and curve L403 represents the frequency response of the headphones with a PU diaphragm of 0.55mm thickness. As shown in Figure 5, the low-frequency resonant peak of curve L401 is around 145Hz, that of curve L402 is around 185Hz, and that of curve L403 is around 230Hz. Comparing curves L401, L402, and L403, the resonant frequencies corresponding to the low-frequency resonant peaks gradually decrease as the diaphragm thickness decreases. When the diaphragm is too thick, the corresponding first resonant frequency is higher, and the flat area of ​​the headphone's output sound is narrower. When the diaphragm is too thin, the diaphragm structure has lower strength and is more prone to failure. Therefore, in some embodiments, when the diaphragm is made of PU material, in order to make the speaker 120 have a flatter output over a wider frequency range, improve the output of the speaker 120, and thus improve the active noise cancellation effect of the headphones on low-frequency environmental noise, the low-frequency resonant frequency of the speaker 120 can be between 100Hz and 300Hz, and the thickness of the diaphragm can be between 0.02mm and 0.07mm. In some embodiments, when the diaphragm is made of PU material, in order to further reduce the low-frequency resonant frequency of the speaker 120, the thickness of the diaphragm can be between 0.035mm and 0.055mm.

[0126] In some embodiments, to further reduce the K-value of the diaphragm, the diaphragm material can be liquid silicone with a lower elastic modulus. In some embodiments, when the diaphragm material is liquid silicone, in order to reduce the resonant frequency of the speaker 120 at low frequencies (e.g., below 300Hz), so that the speaker 120 has a flatter output over a wider frequency range, improve the low-frequency output of the speaker 120, and thus improve the active noise cancellation effect of the headphones on low-frequency ambient noise, the diaphragm thickness can be 0.055mm-0.1mm. It should be noted that the aforementioned diaphragm material refers to the material of the diaphragm as a whole, such as the material of the diaphragm surround, mid-mount, and other structures.

[0127] In some embodiments, to reduce distortion caused by the unstable vibration of the first diaphragm 121-1 or the second diaphragm 121-2, the stability of the structural connection between the first diaphragm 121-1 or the second diaphragm 121-2 and related components can be optimized using component structure optimization. The structure of the diaphragm is described below using the first diaphragm 121-1 as an example. It should be noted that, as a dual-diaphragm loudspeaker, the component structure of the second diaphragm 121-2 is the same as or similar to that of the first diaphragm 121-1, and will not be described again.

[0128] Figure 6 is a structural schematic diagram of a diaphragm assembly according to some embodiments of this specification.

[0129] Referring to Figure 6, the first diaphragm 121-1 includes a folded ring 1211, a center mount 1212, and a fixing ring 1213. The folded ring 1211 surrounds the outer periphery of the center mount 1212, which is connected to the voice coil assembly (e.g., the center mount 1212 of the first diaphragm 121-1 is bonded or welded to the first voice coil 123-1). The portion of the folded ring 1211 radially away from the center mount 1212 is connected to the fixing ring 1213. The support assembly is fixedly connected to the fixing ring 1213 (e.g., the fixing ring 1213 of the first diaphragm 121-1 is bonded or welded to the first support). For details regarding the support assembly, please refer to the relevant descriptions in Figures 65-66.

[0130] It should be noted that the first diaphragm 121-1, which is assembled from the folded ring 1211, the center patch 1212, and the fixing ring 1213, can be understood as a component structure, that is, the first diaphragm 121-1 can be called the first diaphragm component; among them, the area occupied by the center patch 1212 on the first diaphragm 121-1 or the center patch 1212 itself can be regarded as the main area of ​​the first diaphragm 121-1, and the area occupied by the folded ring 1211 on the first diaphragm 121-1 or the folded ring 1211 itself can be regarded as the folded ring area of ​​the first diaphragm 121-1.

[0131] In some embodiments, the fold 1211 may be made of liquid silicone material. In some embodiments, the center patch 1212 may be made of one or more of magnesium-aluminum alloy, carbon fiber, aluminum-coated polymethacrylimide (PMI, also known as rigid foam) or polyethylene naphthalate (PEN).

[0132] This design, using silicone material with high temperature stability as the surround 1211 or the surround area of ​​the diaphragm assembly, effectively improves the temperature stability of the diaphragm assembly, ensuring the sound output and active noise cancellation effects of the speaker 120. Simultaneously, the use of a strong adhesive and high mechanical strength center patch 1212 to establish a structural connection between the voice coil assembly 123 and the surround 1211, and the use of a fixing ring 1213 to establish a structural connection between the support assembly and the surround 1211, effectively enhances the structural stability between the diaphragm assembly and the voice coil assembly 123, overcoming the poor adhesive performance of silicone material. This ensures stable vibration of the diaphragm assembly and the voice coil assembly 123 to produce sound while preventing the voice coil assembly 123 from detaching from the diaphragm assembly during vibration.

[0133] Due to the poor adhesive properties of silicone material, it is difficult to use adhesive to bond and fix the folded ring 1211 to the center patch 1212 and the fixing ring 1213. In some embodiments, the diaphragm assembly (i.e., the first diaphragm 121-1) can be a one-piece structure. For example, the folded ring 1211, the center patch 1212, and the fixing ring 1213 can be integrally injection molded, which can effectively enhance the stability of the structural connection between the components of the diaphragm assembly itself.

[0134] Figure 7 is a partial enlarged schematic diagram of the diaphragm assembly in Figure 6, and Figure 8 is a dimensional schematic diagram of the structure shown in Figure 7.

[0135] Referring to Figures 7 and 8, in some embodiments, the folded ring 1211 may include a first connecting portion 1211-1, a folded ring portion 1211-2, and a second connecting portion 1211-3. The first connecting portion 1211-1, the folded ring portion 1211-2, and the second connecting portion 1211-3 are connected sequentially from the inside to the outside in the radial direction; that is, the folded ring portion 1211-2 is connected around the outer periphery of the first connecting portion 1211-1, and the second connecting portion 1211-3 is connected around the outer periphery of the folded ring portion 1211-2.

[0136] Furthermore, in some embodiments, the folded ring 1211 further includes a third connecting portion 1211-4 and a fourth connecting portion 1211-5. The third connecting portion 1211-4 has one end in the vibration direction connected to the connection between the folded ring portion 1211-2 and the first connecting portion 1211-1. Alternatively, the folded ring portion 1211-2 extends a certain length along the vibration direction towards one side of the magnetic circuit assembly, near one end of the first connecting portion 1211-1 or the center patch 1212, to form the third connecting portion 1211-4. The fourth connecting portion 1211-5 has one end in the vibration direction connected to the connection between the folded ring portion 1211-2 and the second connecting portion 1211-3. Alternatively, the folded ring portion 1211-2 extends a certain length along the vibration direction towards one side of the magnetic circuit assembly, near one end of the second connecting portion 1211-3 or the fixing ring 1213, to form the fourth connecting portion 1211-5.

[0137] In the vibration direction, the inner surface of the first connecting part 1211-1 is attached to the outer surface of the middle patch 1212, and the inner surface of the second connecting part 1211-1 is attached to the outer surface of the fixing ring 1213. In the radial direction, the inner circumferential surface of the third connecting part 1211-4 near the voice coil assembly is attached to the circumferential side of the middle patch 1212, and the outer circumferential surface of the fourth connecting part 1211-5 away from the voice coil assembly 123 is attached to the inner circumferential surface of the fixing ring 1213.

[0138] For ease of distinction and description, in this document, the inner surface refers to the surface closer to the magnetic circuit assembly in the vibration direction, the outer surface refers to the surface farther from the magnetic circuit assembly in the vibration direction, the inner peripheral surface refers to the surface closer to the center point of the fold ring 1211 in the radial direction, and the outer peripheral surface refers to the surface farther from the center point of the fold ring 1211 in the radial direction. For example, the inner surface of the first connecting portion 1211-1 is defined as the first surface P1, the inner surface of the second connecting portion 1211-3 is defined as the second surface P2, the inner peripheral surface of the third connecting portion 1211-4 is defined as the third surface P3, the outer peripheral surface of the fourth connecting portion 1211-5 is defined as the fourth surface P4, and the outer peripheral surface of the third connecting portion 1211-4 is defined as the fifth surface P5.

[0139] With this configuration, based on the first surface P1 and the third surface P3, the folded ring 1211 covers the outer surface and outer peripheral side of the mating center 1212. This can effectively increase the connection area between the folded ring 1211 and the mating center 1212, enhance the connection strength between the folded ring 1211 and the mating center 1212, and provide support for the structural connection between the inner surface of the mating center 1212 and the voice coil assembly.

[0140] In some embodiments, when the first surface P1 is bonded to the outer surface of the middle adhesive 1212, the outer surface of the middle adhesive 1212 may be completely covered and bonded by the first connecting portion 1211-1 or the first surface P1. Alternatively, the first connecting portion 1211-1 or the first surface P1 may circumferentially cover and bond a portion of the outer surface of the middle adhesive 1212. In other embodiments, one or both of the third connecting portion 1211-4 and the fourth connecting portion 1211-5 may be omitted.

[0141] In some embodiments, when the outer surface and outer peripheral side of the center patch 1212 are covered and bonded by the fold ring 1211, the lower surface of the center patch 1212 can also be covered and bonded by the fold ring 1211 to further enhance the stability of the connection between the fold ring 1211 and the center patch 1212.

[0142] Specifically, the surround 1211 also has a fifth connecting portion, which is spaced apart from the first connecting portion 1211-1 in the vibration direction, while the third connecting portion 1211-4 is connected between the fifth connecting portion and the surround portion 1211-2 in the vibration direction. In the vibration direction, the outer surface of the fifth connecting portion is bonded to the edge region of the inner surface of the center mount 1212, while the voice coil assembly is connected to the area of ​​the inner surface of the center mount 1212 not covered by the fifth connecting portion. Thus, the fifth connecting portion further enhances the stability of the structural connection between the surround 1211 and the center mount 1212. To avoid the diaphragm 121b negatively affecting the connection between the voice coil assembly and the center mount 1212, the minimum radial distance between the fifth connecting portion and the voice coil assembly can be set to not less than 0.5 mm.

[0143] In some embodiments, referring to FIG7, the surround portion 1211-2 adopts an arched structure that protrudes from the outer surface of the center patch 1212 or the outer surface of the fixing ring 1213. For example, the surround portion 1211-2 bends and arches away from the voice coil assembly 123 along the vibration direction relative to the first connecting portion 1211-1. In this way, for the loudspeaker 120 as a whole, it is equivalent to the surround portion 1211-2 arching towards the outside of the loudspeaker 120. This not only provides ample space for the magnetic circuit assembly 122 and the like inside the loudspeaker 120, allowing the magnetic circuit assembly 122 to have a larger design size, which is beneficial to enhance the driving force of the magnetic circuit assembly 122 and the voice coil assembly 123 on the diaphragm assembly, but also avoids interference with the sound-generating structure such as the magnetic circuit assembly 122 due to deformation during the vibration of the surround 1211, thus ensuring the quality of the sound output.

[0144] Figure 9 is a schematic diagram of the driving force coefficient of a loudspeaker corresponding to different voice coil assembly movement distances according to some embodiments of this specification. Specifically, Figure 9 shows the BLx curve of the product (BL) of the magnetic flux density (B) of the loudspeaker 120 and the voice coil length (L) as a function of the movement distance (x) of the voice coil assembly 123. Referring to Figure 9, when the voice coil assembly 123 moves to ±0.6 mm, the BLx curve changes by approximately 17%, and when the voice coil assembly 123 moves to ±0.8 mm, the BLx curve changes by approximately 25%. Considering that the KMs curve of the diaphragm assembly 123 is one of the key parameters affecting the distortion of the loudspeaker 120, if the proportion of change of the KMs curve is within a similar range within the movement distance range of the voice coil assembly, the BLx curve of the loudspeaker 120 will have a better match with the KMs curve of the diaphragm assembly, which is beneficial to giving the loudspeaker 120 a lower distortion. For example, when the shape of the KMs curve of the diaphragm assembly and the shape of the BLx curve are a matching "n" shape, the distortion of the loudspeaker 120 is lower. Therefore, by designing the structure and dimensional relationships of the diaphragm assembly, the KMs curve of the diaphragm assembly can be adjusted to match the BLx curve of the speaker 120, thereby obtaining a speaker 120 with lower distortion, thus providing support for enhancing the active noise cancellation of the headphones; this will be explained in detail below.

[0145] In some embodiments, referring to FIG8, the minimum radial distance between the fifth surface P5 and the third surface P3 is defined as the first width Ldc, the minimum radial distance between the fifth surface P5 and the fourth surface P4 is defined as the second width Lm, and the ratio of the first width Ldc to the second width Lm is defined as the first ratio LL; the first ratio LL can be between 0.04 and 0.32, which enables the KMs curve of the diaphragm assembly to match the BLx curve of the speaker 120, thereby giving the speaker 120 a lower distortion.

[0146] Specifically, as the second width Lm changes, different first widths Lac will cause significant changes in the KMs curve shape of the diaphragm assembly, thereby affecting the distortion of the final speaker 120.

[0147] Figure 10 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different first ratios according to some embodiments of this specification. Referring to Figure 10, when the first ratio LL is small (i.e., when the connection area between the surround portion 1211-2 and the center patch 1212 is closer to the arc-shaped endpoint of the inner side of the surround portion 1211-2), the KMs curve of the diaphragm assembly is "U"-shaped. As the first ratio LL increases, the KMs curve of the diaphragm assembly gradually transitions from "U"-shaped to "n"-shaped, making the KMs curve match the BLx curve. Among them, when the first ratio LL is 0.04, although the KMs curve is "U"-shaped, the curve is relatively flat, indicating that the distortion of the speaker 120 is still small at this time. When the first ratio LL is 0.32, the "n"-shaped shape of the KMs curve matches the BLx curve of the speaker 120 better, indicating that the distortion of the speaker 120 is small at this time.

[0148] Therefore, setting the first ratio LL of the surround 1211 to between 0.04 and 0.32 can effectively reduce the distortion of the speaker 120 and ensure that the speaker 120 can provide support for active noise cancellation of the headphones when in use.

[0149] Furthermore, in some embodiments, the first ratio LL can be set to 0.16 to enhance the matching between the KMs curve of the first diaphragm 121-1 and the KMs curve of the second diaphragm 121-2 and the BLx curve of the speaker 120, thereby obtaining a dual-diaphragm speaker with less distortion, thus providing support for improving the active noise cancellation effect of the headphones.

[0150] Figure 11 is another dimensional schematic diagram of the structure shown in Figure 7.

[0151] In some embodiments, referring to FIG11, the minimum radial distance between the third surface P3 and the fourth surface P4 (i.e., the radial width or span of the folded ring portion 1211-2) is defined as the third width Lmar, and the ratio of the average wall thickness Tmar of the folded ring portion 1211-2 to the third width Lmar is defined as the second ratio TL. Considering the relationship between the width and wall thickness of the folded ring portion 1211-2, it not only affects the compliance (S) of the diaphragm assembly, and thus the f0 (i.e., the resonant frequency) of the loudspeaker 120, but also affects the KMs curve; therefore, the second ratio TL may not be greater than 0.12.

[0152] Figure 12 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different second ratios according to some embodiments of this specification. Referring to Figure 12, the smaller the second ratio TL (i.e., the thinner the average wall thickness of the surround portion 1211-2), the flatter the corresponding KMs curve; when the second ratio TL changes from 0.12 to 0.06, the shape of the corresponding KMs curve also changes from a "U" shape to an "n" shape; for example, when the voice coil assembly moves to ±0.6 mm and the second ratio TL is 0.12, the KMs curve changes by about 12%, which is acceptable. Therefore, by keeping the second ratio TL of the surround 1211 no higher than 0.12, the KMs curve can match the BLx curve, which is beneficial for giving the loudspeaker 120 a lower distortion. Exemplarily, the second ratio TL can be set to 0.1, 0.06, or other values ​​less than 0.12.

[0153] Figure 13 is another dimensional schematic diagram of the structure shown in Figure 7.

[0154] In some embodiments, referring to FIG13, the distance between the plane containing the first surface P1 and the second surface P2 (or the height difference between the first surface P1 and the second surface P2 in the vibration direction) is defined as the first height H0, and the ratio of the first height H0 to the third width Lmar is defined as the third ratio HLO. Considering that the width of the folded ring portion 1211-2 and the height difference between the inner and outer ends of the folded ring portion 1211-2 in the radial direction will affect the KMs curve, and thus affect the distortion of the loudspeaker 120, the third ratio HLO may not be greater than 0.232.

[0155] Figure 14 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different third ratios according to some embodiments of this specification. Referring to Figure 14, the smaller the third ratio HLO, the flatter the corresponding KMs curve; when the third ratio HLO changes from 0.232 to 0.072, the corresponding KMs curve gradually flattens; for example, when the voice coil assembly 123 moves to ±0.6mm and the third ratio HLO is 0.232, the KMs curve changes by about 15%, which is acceptable. Therefore, setting the third ratio HLO of the surround 1211 to no greater than 0.232 enables the KMs curve to match the BLx curve, thereby obtaining a loudspeaker 120 with lower distortion.

[0156] Figure 15 is another dimensional schematic diagram of the structure shown in Figure 7.

[0157] In some embodiments, referring to FIG15, the distance from the vertex of the folded ring portion 1211-2 to the plane containing the second surface P2 (which can also be understood as the arch height of the folded ring portion 1211-2) is defined as the second height Hm, and the ratio of the first height H0 to the second height Hm is defined as the fourth ratio HTO. Considering that the arch height of the folded ring portion 1211-2 and the height difference between the inner and outer ends of the folded ring portion 1211-2 will also affect the KMs curve, and thus affect the distortion of the speaker 120; therefore, the fourth ratio HTO can be no greater than 0.36.

[0158] Figure 16 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different fourth ratios according to some embodiments of this specification. Referring to Figure 16, the smaller the fourth ratio HTO, the flatter the corresponding KMs curve; when the fourth ratio HTO changes from 0.36 to 0.11, the corresponding KMs curve gradually flattens; for example, when the voice coil assembly 123 moves to ±0.6mm and the fourth ratio HTO is 0.36, the corresponding KMs curve changes by about 17%, which is acceptable. Therefore, by setting the fourth ratio HTO of the surround 1211 to no greater than 0.36, the KMs curve can be matched with the BLx curve, thereby obtaining a loudspeaker 120 with low distortion.

[0159] Furthermore, in some embodiments, the fourth ratio HTO can be set in the range of 0.36 to 0.11, for example, the fourth ratio HTO is 0.18, 0.24, 0.3, etc. In this case, the KMs curve is flatter, the distortion of the speaker 120 is lower, and it provides support for active noise cancellation of the headphones in a wider frequency range.

[0160] Figure 17 is another dimensional schematic diagram of the structure shown in Figure 7.

[0161] In some embodiments, referring to Figure 17, the folded ring portion 1211-2 is radially divided into a first arc-shaped region A1, a second arc-shaped region A2, and a third arc-shaped region A3, with the arc length of each arc-shaped region being one-third of the arc length of the folded ring portion 1211-2. The first arc-shaped region A1 is the area of ​​the folded ring portion 1211-2 near the fixing ring 1213 or adjacent to the second connecting portion 1211-3, and the third arc-shaped region A3 is the area of ​​the folded ring portion 1211-2 near the center patch 1212 or adjacent to the second connecting portion 1211-3. The ratio of the average wall thickness of the first arc-shaped region A1 to the average wall thickness of the second arc-shaped region A2, and the ratio of the average wall thickness of the third arc-shaped region A3 to the average wall thickness of the second arc-shaped region A2, are both defined as the fifth ratio TT. Considering the wall thickness relationship between different regions of the folded ring portion 1211-2, which has a significant impact on the shape of the KMs curve, the fifth ratio TT can be no greater than 1.2.

[0162] Figure 18 is a schematic diagram of the KMs curves of the diaphragm assembly corresponding to different fifth ratios according to some embodiments of this specification. Referring to Figure 18, when the fifth ratio TT changes from 1.2 to 0.8, the corresponding KMs curve gradually flattens out. For example, when the voice coil assembly moves to ±0.6 mm and the fifth ratio TT is 1.2, the KMs curve changes by about 18%, which is acceptable. Therefore, by setting the fifth ratio TT of the surround 1211 to no greater than 1.2 (e.g., 1.1, 1.0, 0.9, 0.8, etc.), the KMs curve can be matched with the BLx curve, thereby obtaining a speaker 120 with lower distortion. When the speaker 120 is applied to open-back headphones, it can provide support for active noise cancellation over a wider frequency range.

[0163] In some embodiments, the fifth ratio TT can be set to no more than 1.0, that is, the wall thickness of the first arc region A1 and the third arc region A3 is less than the wall thickness of the second arc region A2; thus, the corresponding KMs curve is flatter and the KMs curve is more in line with the BLx curve.

[0164] In some embodiments, a center patch 1212 with higher strength and height can be provided to improve the high-frequency vibration characteristics of the speaker 120, thereby helping the headphones to perform active noise cancellation over a wider frequency range. In some embodiments, the center patch 1212 can adopt an arched structure to give the center patch 1212 higher strength and height, which is beneficial to improving the high-frequency vibration characteristics of the speaker 120, thereby helping the headphones to perform active noise cancellation over a wider frequency range.

[0165] Figure 19 is a schematic diagram of the structure of the in-line sticker according to some embodiments of this specification.

[0166] In some embodiments, referring to Figures 6 and 19, the center patch 1212 can adopt an arched structure protruding away from the voice coil assembly along the vibration direction. Specifically, the center patch 1212 has a central region 1212-1, a connecting region 1212-2, and an edge region 1212-3 that are sequentially connected from the inside to the outside in the radial direction. Alternatively, the connecting region 1212-2 can be understood as surrounding and connecting to the outer periphery of the central region 1212-1, and the edge region 1212-3 surrounding and connecting to the outer periphery of the connecting region 1212-2. The connecting region 1212-2 vibrates... The center patch 1212 is inclined relative to the edge region 1212-3 and the center region 1212-1 in the vibration direction, so that there is a height difference between the geometric center of the center region 1212-1 and the plane where the edge region 1212-3 is located in the vibration direction, thereby constructing a dome-shaped structure. The edge region 1212-3 is connected to the surround 1211 and the voice coil assembly. For example, the first connecting part 1211-1 is attached to the outer surface of the edge region 1212-3 in the vibration direction, and the voice coil assembly is connected to the inner surface of the edge region 1212-3 in the vibration direction. For example, the center patch 1212 can be made of carbon fiber material.

[0167] Furthermore, in some embodiments, the edge region 1212-3 may be a planar structure perpendicular to the vibration direction, the center region 1212-1 may be an arc-shaped structure protruding away from the voice coil assembly in the vibration direction, and the connecting region 1212-2 is adaptively connected between the edge region 1212-3 and the center region 1212-1.

[0168] The arched center patch 1212 can also prevent the surround 1211 from shaking during large vibrations, thus ensuring that the voice coil assembly and the magnetic circuit assembly will not collide and produce sound. In addition, the edge area 1212-3 can provide ample connection area for the voice coil assembly and the surround 1211, ensuring that the voice coil assembly and the surround 1211 can be stably connected to the center patch 1212.

[0169] In other embodiments, the center patch 1212 may also adopt other suitable arched structures, such as omitting the connecting area 1212-2, adopting an arc-shaped structure that protrudes away from the voice coil assembly in the vibration direction, and the edge area 1212-3 surrounding the center area 1212-1 and connecting to the edge of the center area 1212-1; all such details are omitted here. However, it should be noted that the diaphragm of the component structure in the above embodiments can be applied to the loudspeaker 120 of any embodiment provided in this application as needed.

[0170] In some embodiments, the sound-generating assembly may include a loudspeaker 120 and a limiting assembly 130. The limiting assembly 130 may be used to position and confine the loudspeaker 120 within the first housing 110. Furthermore, the limiting assembly 130 may also be used to cooperate with the loudspeaker 120 to form an acoustic cavity between the corresponding housing sidewall of the first housing 110. Specifically, the loudspeaker 120 is arranged at intervals with the inner sidewall 110a and the outer sidewall 110b along the vibration direction, while the limiting assembly 130 positions and confines the loudspeaker 120 between the inner sidewall 110a and the outer sidewall 110b, thereby forming a first acoustic cavity 111-1 with the loudspeaker 120 and the inner sidewall 110a, and forming a second acoustic cavity 111-2 with the loudspeaker 120 and the outer sidewall 110b.

[0171] The limiting component 130 not only affects the structural relationship between the speaker 120 and the first housing 110, but also affects the structure of the acoustic cavity, thereby affecting the second resonant frequency of the headphone's output sound, and thus affecting the headphone's active noise reduction in a wider frequency range.

[0172] Figure 20 is a cross-sectional structural diagram of the sound-generating part in the minor axis direction according to some embodiments of this specification; Figure 21 is an exploded structural diagram of the sound-generating part according to some embodiments of this specification; Figure 22 is a structural schematic diagram of the sound-generating component in the sound-generating part according to some embodiments of this specification; Figure 23 is an exploded structural diagram of the sound-generating component according to some embodiments of this specification; and Figure 24 is a cross-sectional structural diagram of the sound-generating component according to some embodiments of this specification. The limiting component 130 and its related structures will be described below with reference to Figures 20-24.

[0173] In some embodiments, the limiting component 130 is connected between the speaker 120 and the first housing 110. Exemplarily, a portion of the limiting component 130 is connected between the speaker 120 and the inner sidewall 110a of the first housing 110, and another portion is connected between the speaker 120 and the outer sidewall 110b of the first housing 110.

[0174] When the loudspeaker 120 together with the limiting component 130 is installed in the first housing 110, the connection between the limiting component 130 and the housing sidewall of the first housing 110 (it should be noted that the connection can be adhesive, snap-fit, or elastic abutment, etc.) can be used to make the first diaphragm 121-1 and the inner sidewall 110a opposite each other in the vibration direction, and cooperate with the loudspeaker 120 and the inner sidewall 110a to form a first acoustic cavity 111-1 that connects the first sound outlet 112-1 and the tuning hole 113-3. The limiting component 130 can also make the second diaphragm 121-2 and the outer sidewall 110b opposite each other in the vibration direction, and cooperate with the loudspeaker 120 and the outer sidewall 110b to form a second acoustic cavity 111-2 that connects the second sound outlet 112-2.

[0175] Based on this, the limiting component 130 can be used to securely limit the speaker 120 to a predetermined position within the first housing 110, thereby forming a corresponding acoustic cavity between the speaker 120 and the first housing 110, creating conditions for improving the output performance of the headphones; at the same time, the limiting component 130 can also be combined with the speaker 120 to form a relatively complete functional unit (i.e., a sound-generating component), which is beneficial for the disassembly and maintenance of the sound-generating part 100, and also for the design of related structures of the first housing 100 (such as the sound outlet, the tuning port 113-3, etc.) to meet the need for active noise cancellation in a wider frequency range.

[0176] In some embodiments, the limiting component 130 can be sealingly connected between the speaker 120 and the first housing 110. Specifically, a portion of the limiting component 130 is sealingly connected to the speaker 120, and another portion is sealingly connected to the first housing 110. Simultaneously, a sealed enclosure structure is formed between the inner sidewall 110a and the first diaphragm 121-1, and a sealed enclosure structure is formed between the outer sidewall 110b and the second diaphragm 121-2. Exemplarily, the limiting component 130 has a ring-shaped structure with a centrally located sound guide hole. In the vibration direction, the sound guide hole, the first sound outlet hole 112-1, the second sound outlet hole 112-2, the first diaphragm 121-1, and the second diaphragm 121-2 of the limiting component 130 can at least partially overlap. The sound guide hole can connect the cavity spaces on both sides of the limiting component 130 to form a complete acoustic cavity.

[0177] In some embodiments, the limiting component 130 is fixedly connected to the speaker 120 to form an integral structure; the limiting component 130 elastically abuts against the first housing 110. Exemplarily, the end of the limiting component 130 near the inner sidewall 110a in the vibration direction elastically abuts against the inner sidewall 110a, and the end near the outer sidewall 110b elastically abuts against the outer sidewall 110b. This allows the limiting component 130 to be combined with the speaker 120 to form a functional structure relatively independent of the first housing 110, which helps reduce the difficulty of assembling and disassembling the sound-emitting part 100.

[0178] In some embodiments, referring to Figures 22 to 24, the limiting component 130 includes a second housing and a sealing ring. The second housing is disposed inside the first housing 110. The speaker 120 is disposed inside the second housing and fixedly connected to it. The sealing ring is connected between the second housing and the first housing 110. In some embodiments, the sealing ring includes a first sealing ring 131 and a second sealing ring 132, and the speaker 120 is sealed and fitted to the second housing. A sound guide hole is provided on the second housing. In some embodiments, the first housing 110 and / or the second housing are provided with sound guide holes. The sound guide hole on the second housing can conduct the cavity space on both sides of the second housing, and the sound guide hole on the first housing 110 can conduct the cavity space on both sides of the first housing 110, to form a complete acoustic cavity.

[0179] For ease of distinction and description, the shell wall of the second housing that is spaced apart from the inner sidewall 110a in the vibration direction is defined as the first transverse sidewall; the shell wall of the second housing that is spaced apart from the outer sidewall 110b in the vibration direction is defined as the second transverse sidewall; and the shell wall of the second housing that surrounds the vibration direction is defined as the longitudinal sidewall. Alternatively, it can be understood that the first transverse sidewall is disposed facing the inner sidewall (or speaker 120) within the first acoustic cavity 111-1, and the second transverse sidewall is disposed facing the outer sidewall 110b (or speaker 120) within the second acoustic cavity 111-2. The speaker 120 is located between the first and second transverse sidewalls in the vibration direction. Furthermore, one end of the first sealing ring 131 is fixed to the first transverse sidewall in the vibration direction, and the other end abuts against the inner sidewall 110a; one end of the second sealing ring 131 is fixed to the second transverse sidewall in the vibration direction, and the other end abuts against the outer sidewall 110b.

[0180] The limiting component 130 includes a first sound guide hole 130-1 that passes through the first transverse sidewall and the first sealing ring 131, and a second sound guide hole 130-2 that passes through the second transverse sidewall and the second sealing ring 132. The first sound guide hole 130-1 connects to the first acoustic cavity 111-1. This can also be understood as the first acoustic cavity 111-1 including the cavity space between the first transverse sidewall and the inner sidewall 110a, and the cavity space between the first transverse sidewall and the speaker 120 (e.g., the second diaphragm 121-1). These two cavity spaces located on either side of the first transverse sidewall are connected by the first sound guide hole 130-1 to form the complete first acoustic cavity 111-1. Similarly, the second sound guide hole 130-2 connects to the second acoustic cavity 111-2.

[0181] Based on this, using the second housing as the outer protective structure of the speaker 120 provides a relatively stable structural assembly space for the speaker. This not only facilitates the construction of the sound-generating components into a complete functional unit, but also promotes the miniaturization and weight reduction of the sound-generating components or the sound-generating section 100. For example, the second housing can be made of metal, thereby ensuring the mechanical strength of the second housing while making the shell wall thinner and lighter. Simultaneously, it also facilitates the design of the internal acoustic structure of the sound-generating section 100, providing support for active noise cancellation and other functions.

[0182] In some embodiments, on a reference plane perpendicular to the vibration direction, the projections of the sound guide hole, the first sound outlet hole 112-1, the second sound outlet hole 112-2, the first diaphragm 121-1, and the second diaphragm 121-2 of the limiting component 130 at least partially overlap to ensure that the sound output of the speaker 120 is delivered to the outside of the first housing 110.

[0183] For example, in some embodiments, the projection of the first sound outlet 112-1 falls within the projection of the first sound guide 130-1 on a reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, the overlapping area of ​​the projection of the first sound outlet 112-1 and the projection of the first sound guide 130-1 on the reference plane perpendicular to the vibration direction has a projected area not less than 80% of the projected area of ​​the projection of the first sound guide 130-1. Since the sound generated by the first diaphragm 121-1 in the first acoustic cavity 111-3 is connected to the first sound outlet 112-1 through the first sound guide 130-1 and then output to the outside of the first housing 110 through the first sound outlet 112-1, the overlapping area of ​​the first sound outlet 112-1 and the first sound guide 130-1 can be regarded as the neck of the first Helmholtz resonator model corresponding to the first acoustic cavity 111-3. By designing the ratio of the overlapping area to the area of ​​the first sound guide hole 130-1, the resonant frequency of the first acoustic cavity 111-3 can be adjusted. This allows the air pushed by the diaphragm in the sound guide hole of the limiting component 130 to be smoothly pushed out from the first sound outlet hole 112-1, ensuring the acoustic output of the speaker 120 and providing support for shifting the peak resonant frequency of the second resonant peak as high as possible. Preferably, in some embodiments, on a reference plane perpendicular to the vibration direction, the projection of the second sound outlet hole 112-2 falls within the projection of the second sound guide hole 130-2. Alternatively, in some embodiments, on a reference plane perpendicular to the vibration direction, the overlapping area of ​​the projection of the second sound outlet hole 112-2 and the projection of the second sound guide hole 130-2 has a projected area not less than 80% of the projected area of ​​the second sound guide hole 130-2. This configuration allows the air pushed by the diaphragm in the sound guide hole of the limiting component 130 to be smoothly pushed out from the second sound outlet 112-2, ensuring the acoustic output of the speaker 120.

[0184] Similarly, in some embodiments, the projection of the first diaphragm 121-1 falls within the projection of the first sound guide hole 130-1 on the reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, the overlapping area of ​​the projection of the first diaphragm 121-1 and the projection of the first sound guide hole 130-1 on the reference plane perpendicular to the vibration direction has a projected area not less than 80% of the projected area of ​​the first diaphragm 121-1. This arrangement ensures that when the first diaphragm 121-1 vibrates, the air propelled by the first diaphragm 121-1 can smoothly enter the sound guide hole of the limiting component 130, maximizing the acoustic output of the speaker 120. Preferably, in some embodiments, the projection of the second diaphragm 121-2 falls within the projection of the second sound guide hole 130-2 on the reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, on a reference plane perpendicular to the vibration direction, the overlapping area of ​​the projection of the second diaphragm 121-2 and the projection of the second sound guide 130-2 is not less than 80% of the projected area of ​​the second diaphragm 121-2. This arrangement ensures that when the second diaphragm 121-2 vibrates, the air propelled by the second diaphragm 121-2 can smoothly enter the sound guide of the limiting component 130, maximizing the acoustic output of the speaker 120.

[0185] Additionally, referring to Figure 20, based on the first sealing ring 131 and the second sealing ring 132, the sound-generating component can be sealed and fixed inside the first housing 110 (i.e., the accommodating cavity) by means of interference fit, for example, the first sealing ring 131 elastically abuts against the inner side wall 110a, while the second sealing ring 132 elastically abuts against the outer side wall 110b; in this way, the speaker 120 is sealed and fixed inside the first housing 110 from both sides in the vibration direction by using the first sealing ring 131 and the second sealing ring 132, thereby sealing and forming the first acoustic cavity 111-1 and the second acoustic cavity 111-2.

[0186] It should be noted that the "boundary of the first acoustic cavity 111-1" mentioned in the foregoing embodiments can be defined by the first sealing ring 131. That is, it can be understood that the projection of the first sealing ring 131 onto the reference plane perpendicular to the vibration direction is the boundary of the first acoustic cavity 111-1.

[0187] In some embodiments, the deformation resistance of the first sealing ring 131 and the second sealing ring 132 is less than that of the second housing. For example, the first sealing ring 131 and the second sealing ring 132 can be made of elastic materials such as silicone, while the second housing can be made of metal materials such as aluminum alloy or other materials such as plastic with a material hardness greater than that of the sealing ring.

[0188] For example, the first sealing ring 131 and the second sealing ring 132 are made of elastic materials such as silicone, and the first sealing ring 131 and the second sealing ring 132 can be integrally molded into the second housing by injection molding, die-cutting or other methods. In this way, the limiting component 130 can be constructed into a relatively independent and complete structural component, which helps to reduce the difficulty of disassembling and assembling the sound-generating component and the sound-generating part 100, and enhances the structural stability of the sound-generating component and even the sound-generating part 100.

[0189] In some embodiments, a reinforcing structure is provided at the junction of the second housing and the first sealing ring 131 (and the second sealing ring 132). The reinforcing structure may be a serrated structure, a hole structure, etc., provided on the first or second transverse sidewall. The reinforcing structure enhances the stability of the connection between the first sealing ring 131 (and the second sealing ring 132) and the second housing structure, and prevents the sealing ring from falling off when the sound-generating part 100 is disassembled or assembled.

[0190] In some embodiments, referring to Figures 22 to 24, the second housing is a split structure, including a first cover 133 and a second cover 134; wherein, one end of the speaker 120 in the vibration direction extends into the first cover 133 and the other end extends into the second cover 134; it can also be understood that the first cover 133 and the second cover 134 respectively cover or shield the opposite ends of the speaker 120 in the vibration direction. The side wall of the first cover 133 between the speaker 120 and the inner side wall 110a is the first transverse side wall, and the side wall of the second cover 134 between the speaker 120 and the outer side wall 110b is the second transverse side wall. The side walls of the first cover 133 and the second cover 134 that surround the speaker 120 in the vibration direction and are fixedly connected to the speaker 120 are their respective longitudinal side walls.

[0191] On the one hand, by utilizing the relative positional relationship between the first mask 133, the second mask 134 and the speaker 120, a receiving gap 130-4 surrounding the speaker 120 can be formed between the first mask 133 and the second mask 134. The receiving gap 130-4 provides structural assembly space for circuit boards 150 and other components that are electrically connected to the speaker 120 and microphone assembly. For example, wires, ribbon cables, flexible printed circuit boards (FPCs) can be accommodated and fixed within the receiving gap 130-4, thereby making full use of the structural space, effectively improving the structural compactness of the sound-generating components, and facilitating the miniaturization of the sound-generating part 100 and even headphones.

[0192] On the other hand, by constructing the first mask 133 and the first sealing ring 131 as independent and complete structural components, and the second mask 134 and the second sealing ring 132 as independent and complete structural components, it is also beneficial to disassemble and assemble the speaker 120 and the limiting component 130, thereby reducing the difficulty of disassembling and assembling the sound-generating component.

[0193] In some embodiments, the limiting component 130 may omit the second housing, and a sealing connection may be directly established between the speaker 120 and the first housing 110 using the first sealing ring 131 and the second sealing ring 132. For example, the first sealing ring 131 is clamped and fixed between the speaker 120 and the inner sidewall 110a, and together with the speaker 120 and the inner sidewall 110a, forms a first acoustic cavity 111-1; the second sealing ring 132 is clamped and fixed between the speaker 120 and the outer sidewall 110b, and together with the speaker 120 and the outer sidewall 110b, forms a second acoustic cavity 111-2. In this case, the first sealing ring 131 and the second sealing ring 132 may adopt an annular structure, and corresponding sound guide holes may be formed by openings in the first sealing ring 131 and the second sealing ring 132.

[0194] In other embodiments, the limiting component 130 may omit the first sealing ring 131 and the second sealing ring 132, and utilize the interference fit between the second housing (e.g., the first mask 133 and the second mask 134) and the first housing 110 (e.g., the inner sidewall 110a and the outer sidewall 110b) to form the first acoustic cavity 111-1 and the second acoustic cavity 111-2.

[0195] In other embodiments, the limiting component 130 may also adopt other suitable structures, as long as it can securely fix the speaker 120 within the first housing 110, or enable the speaker 120 to divide the accommodating cavity into a first acoustic cavity 111-1 and a second acoustic cavity 111-2. These will not be elaborated upon here.

[0196] In some embodiments, referring to FIG21, the first housing 110 is provided with an opening structure and a positioning structure (for ease of distinction and description, the positioning structure is defined as the third positioning structure); wherein, the opening structure can be formed by the inner sidewall 110a, the outer sidewall 110b, the upper sidewall 110c and the lower sidewall 110d, and the opening structure can also be provided through the bottom sidewall or the top sidewall of the first housing 110 in the short axis direction; that is, the first housing 110 can be formed by splicing multiple housing sidewalls, for example, the inner sidewall 110a, the outer sidewall 110b, the upper sidewall 110c and the lower sidewall 110d are an integral structure, and the bottom sidewall and the top sidewall are provided to cover the opening structure and together with other sidewalls form the receiving cavity of the first housing 110.

[0197] The opening structure is connected to the accommodating cavity and is mainly used to guide the sound-generating component into and out of the accommodating cavity, so as to realize the assembly and disassembly of the sound-generating component and the first housing 110. The third positioning structure can be set in the accommodating cavity. For example, the third positioning structure may include protrusions, steps, etc. on the housing sidewalls such as the inner sidewall 110a, outer sidewall 110b, upper sidewall 110c, and lower sidewall 110d. It is mainly used to hold the limiting component 130 to limit the position of the sound-generating component in the accommodating cavity, thereby providing support for the precise and rapid assembly of the sound-generating component.

[0198] In some embodiments, the first lateral sidewall and the first sound guide hole 130-1, the second lateral sidewall and the second sound guide hole 130-2 can provide support for adjusting the resonant frequency, acoustic impedance, and sound pressure level of the sound output from the corresponding acoustic cavity, so as to enhance the active noise reduction effect.

[0199] For example, the first sound guide hole 130-1 includes an opening of the first sealing ring 131 and an opening of the first transverse sidewall. On a reference plane perpendicular to the vibration direction, the projections of the opening of the first transverse sidewall, the projection of the first sound outlet hole 112-1, and the projection of the opening of the first sealing ring 131 have a first overlapping region. The proportion of the projection of the opening of the first transverse sidewall in the first overlapping region is greater than the proportion of the projection of the first sound outlet hole 112-1. For example, on the reference plane, within the first overlapping region, the proportion of the projected area of ​​the opening of the first transverse sidewall can be greater than 30% (e.g., greater than 80%), while the proportion of the projected area of ​​the first sound outlet hole 112-1 can be between 20% and 30%. This minimizes the impact on sound output caused by the small opening areas of the first sound guide hole 130-1 and the second sound guide hole 130-2.

[0200] Preferably, the second sound guide hole 130-2 includes the opening of the second sealing ring 132 and the opening of the second transverse sidewall. On a reference plane perpendicular to the vibration direction, the projections of the opening of the second transverse sidewall, the projection of the second sound outlet hole 112-2, and the projection of the opening of the second sealing ring 132 have a second overlapping region. The proportion of the projection of the opening of the second transverse sidewall in the second overlapping region is greater than the proportion of the projection of the second sound outlet hole 112-2. For example, on the reference plane, within the second overlapping region, the proportion of the projected area of ​​the opening of the second transverse sidewall can be greater than 30% (e.g., greater than 80%), while the proportion of the projected area of ​​the second sound outlet hole 112-2 can be between 20% and 30%. This minimizes the impact on sound output caused by the small opening areas of the first sound guide hole 130-1 and the second sound guide hole 130-2.

[0201] In some embodiments, please refer to Figures 22 and 23. The second housing has a rib structure 130-3, which is disposed on the first transverse sidewall and the second transverse sidewall. For ease of distinction and description, the rib structure 130-3 of the first transverse sidewall is defined as the first rib structure, and the rib structure 130-3 of the second transverse sidewall is defined as the second rib structure. The first rib structure is located in the first sound guide hole 130-1, and the second rib structure is located in the second sound guide hole 130-2.

[0202] The first rib structure can be used to support and fix the first acoustic barrier in the aforementioned embodiment within the first acoustic cavity 111-1. For example, the first acoustic barrier covers the first sound guide hole 130-1 and is fixed to the side of the first transverse sidewall facing the inner sidewall 110a through the first rib structure. The second rib structure can be used to support and fix the second acoustic barrier in the aforementioned embodiment within the second acoustic cavity 111-1. For example, the second acoustic barrier covers the second sound guide hole 130-2 and is fixed to the side of the second transverse sidewall facing the outer sidewall 110b through the second rib structure.

[0203] On the one hand, the rib structure 130-3 can be used to adjust the opening area, shape, and distribution of the corresponding sound guide holes, thereby adjusting the acoustic characteristics or sound output of the corresponding acoustic cavity. For example, the rib structure 130-3 can be used to construct the corresponding sound guide holes into a mesh structure. On the other hand, the acoustic barrier can be fixed to the corresponding rib structure 130-3 and the corresponding sidewall of the limiting component 130 by means of bonding or welding, thereby preventing the acoustic barrier from vibrating due to air vibration when the speaker 120 is working, thus avoiding adverse effects on the sound output (such as the frequency response curve) and ensuring the active noise cancellation effect. If the number of rib structures 130-3 is too small, the acoustic barrier may not be firmly fixed, and the acoustic barrier may vibrate and produce noise; if the number of rib structures 130-3 is too large, the actual area of ​​the corresponding sound guide holes will be too small, affecting the resonant frequency of the corresponding acoustic cavity, affecting the second resonant frequency of the headphone's output sound, and thus affecting the active noise cancellation effect of the headphone. In some embodiments, in order to ensure the active noise cancellation effect of the headphones and avoid noise generated by the vibration of the acoustic barrier, the number of rib structures 130-3 (e.g., the first rib structure or the second rib structure) can be 4.

[0204] In some embodiments, referring to FIG24, when the second housing has a first transverse sidewall and a second transverse sidewall, the minimum distance between the first transverse sidewall and the center of the main body region of the first diaphragm 121-1 is greater than the maximum amplitude of the vibration of the main body region toward the inner sidewall 110a, and the minimum distance between the second transverse sidewall and the center of the main body region of the second diaphragm 121-2 is greater than the maximum amplitude of the vibration of the main body region toward the outer sidewall 110b.

[0205] Therefore, by limiting the distance between the diaphragm amplitude and the corresponding sidewall, collisions with the limiting component 130 during diaphragm vibration can be avoided, thus ensuring sound output performance.

[0206] It should be noted that the diaphragm typically includes a main body region and a surround region surrounding the main body region; wherein, the main body region can move in the vibration direction by the driving force generated by the cooperation of the magnetic circuit assembly and the voice coil assembly in the speaker 120, thereby generating sound by pushing or squeezing the air inside the first housing 110 or the speaker 120; while the surround region can undergo elastic deformation as the main body region moves, providing elastic restoring force for the main body region.

[0207] In addition, in some embodiments where the second housing is omitted or the second housing does not have a first or second lateral sidewall, in order to avoid the diaphragm colliding with the corresponding housing sidewall in the first housing 110 during vibration, the minimum distance in the vibration direction between the center of the main body region of the first diaphragm 121-1 and the inner sidewall 110a is set to be greater than the maximum amplitude of the main body region vibrating towards the inner sidewall 110a, and the minimum distance in the vibration direction between the center of the main body region of the second diaphragm 121-2 and the outer sidewall 110b is set to be greater than the maximum amplitude of the main body region vibrating towards the outer sidewall 110b.

[0208] In some embodiments, referring to FIG24, the first transverse sidewall and the second transverse sidewall each have a central portion and an arcuate portion surrounding the central portion, and one end of the arcuate portion away from the central portion is connected to the longitudinal sidewall of the second housing; wherein, in the vibration direction, the central portion of the first transverse sidewall faces the main body region of the first diaphragm 121-1 (at this time, the first sound guide hole 130-1 can be disposed in the central portion of the first transverse sidewall), the arcuate portion of the first transverse sidewall faces the folded ring region of the first diaphragm 121-1, the central portion of the second transverse sidewall faces the main body region of the second diaphragm 121-2 (at this time, the second sound guide hole 130-2 can be disposed in the central portion of the second transverse sidewall), and the arcuate portion of the second transverse sidewall faces the folded ring region of the second diaphragm 121-2.

[0209] On one hand, a second clearance space 130-5 can be formed between the folded area of ​​the first diaphragm 121-1 and the arcuate portion of the first transverse sidewall. When the first diaphragm 121-1 vibrates, the second clearance space 130-5 avoids the folded area of ​​the first diaphragm 121-1. Simultaneously, another second clearance space 130-6 can be formed between the folded area of ​​the second diaphragm 121-2 and the arcuate portion of the second transverse sidewall. When the second diaphragm 121-2 vibrates, the second clearance space 130-6 avoids the folded area of ​​the second diaphragm 121-2. In summary, the clearance spaces prevent the folded area of ​​the diaphragm from colliding with the limiting component 130 during vibration, thus ensuring sound output performance.

[0210] On the other hand, compared to the solution where the transverse and longitudinal sidewalls are connected at right angles, the arc-shaped portion forms an arc transition structure between the transverse and longitudinal sidewalls. This allows the first housing to be constructed in a form that adapts to the second housing, making the corner areas between adjacent sidewalls of the first housing more curved and smooth, avoiding more prominent sharp edges. In this way, without affecting the diaphragm vibration, the comfort of the sound-emitting part 100 or the headphones can be improved, and the appearance of the sound-emitting part 100 can also be improved. At the same time, it is also convenient to adapt the longitudinal sidewall to the outer contour structure of the speaker 120. For example, the longitudinal sidewall can be structurally adapted and fixed to the bracket in the speaker 120, so that the speaker 120 can be stably positioned and fixed inside the second housing.

[0211] In some embodiments, for a speaker 120 whose first diaphragm 121-1 and second diaphragm 121-2 vibrate synchronously and in the same direction, in order to make the frequency response curve of the sound output by the speaker 120 have a flatter region over a wider frequency range, the number, shape, size, and position of one or more acoustic structures (e.g., sound holes, acoustic cavities) of the sound-emitting part 100 can be designed to increase the resonant frequency of the second resonant peak, optimize the frequency response curve of the sound output by the headphones (specifically, the first sound hole 112-1), thereby supporting active noise cancellation in a wider frequency range and improving the sound output effect of the headphones.

[0212] Figure 25 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different sizes of sound outlets according to some embodiments of this specification. It should be noted that Figure 25 is based on data measured under the condition that the first sound outlet 112-1 and the second sound outlet 112-2 are single holes with the same shape (e.g., the shorter side dimension is half the longer side dimension); it can be understood that the area of ​​the housing sidewall of the first housing 110 remains unchanged, the width dimension of the sound outlet remains unchanged, and the ratio of the length dimension of the sound outlet represents the change in the size of the sound outlet.

[0213] In Figure 25, curve L421 represents the frequency response when the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 is 0.1; curve L422 represents the frequency response when the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 is 0.3; curve L423 represents the frequency response when the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 is 0.5; curve L424 represents the frequency response when the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 is 0.7; curve L425 represents the frequency response when the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 is 0.9; and curve L426 represents the total sound pressure level of the loudspeaker 120, which can be considered as the output sound pressure level of the loudspeaker 120 when it is not enclosed by the first housing 110. The sound outlets with different long side dimensions have the same width and are located at the center of the corresponding inner and outer side walls.

[0214] As shown in Figure 25, as the size of the sound outlet gradually decreases, the resonance peak of the sound-emitting part 100 at high frequencies (e.g., above 4.5kHz) gradually shifts forward, and the peak resonant frequency of the high-frequency resonance peak of curve L422 is around 10kHz.

[0215] Based on this, in some embodiments, referring to Figures 26A to 26C, and Figures 32A and 32B, the first sound outlet 112-1 and the second sound outlet 112-2 can adopt a single-hole structure, and the ratio of the size of the first sound outlet 112-1 and / or the second sound outlet 112-2 to the corresponding size of the first housing 110 is not less than 0.3. For example, when the length of the first housing 110 and the sound outlet in the long axis direction is greater than their respective width in the short axis direction, the ratio of the long side dimension of the sound outlet to the long side dimension of the first housing 110 can be not less than 0.3; for example, the ratio of the length of the first sound outlet 112-1 in the long axis direction to the length of the inner sidewall in the long axis direction can be not less than 0.3, and the ratio of the length of the first sound outlet 112-1 in the long axis direction to the length of the outer sidewall in the long axis direction can be not less than 0.3. When the outline of the sound-emitting part 100 is a circular, isocentrically symmetrical geometric shape, the ratio of the radius of the sound outlet to the radius of the corresponding sidewall of the first housing 110 can be no less than 0.3. This ensures that the resonant frequency of the corresponding acoustic cavity is no less than 1kHz, guaranteeing that the second resonant peak of the sound output through the sound outlet shifts to the higher frequency range. Ultimately, this results in a flatter output across a wider frequency range for the headphones, improving their active noise cancellation performance in open-back environments with higher ambient noise levels.

[0216] Figures 26A-26C are schematic diagrams showing different positions of the sound outlet according to some embodiments of this specification, and Figure 27 is a schematic diagram of the frequency response curves of the loudspeaker corresponding to the different positions of the sound outlet according to some embodiments of this specification. In Figure 26A, the sound outlet (e.g., the first sound outlet 112-1) is located at the center of the surface of the first housing 110; in Figure 26B, the sound outlet (e.g., the first sound outlet 112-1) is eccentrically positioned with respect to the surface of the first housing 110 in the length direction; and in Figure 26C, the sound outlet (e.g., the first sound outlet 112-1) is eccentrically positioned with respect to the surface of the first housing 110 in the width direction. It should be noted that Figure 27 shows data measured under the condition that both the first sound outlet 112-1 and the second sound outlet 112-2 are single holes, with the same shape, size, and position.

[0217] In Figure 27, curve L 441 Curve L 442 Curve L 443 Curve L 444 The corresponding sound outlets are all eccentrically positioned along the long side of the surface of the first housing 110. Curve L 441 This indicates that the distance between the center of the sound hole and the center of the corresponding surface along the length direction is 1 mm; curve L 442 The distance along the length direction between the center of the sound hole and the center of the corresponding surface is 3 mm; curve L 443 The distance along the length direction between the center of the sound hole and the center of the corresponding surface is 5 mm; curve L 444 This indicates that the distance between the center of the sound outlet and the center of the corresponding surface in the length direction is 0mm, meaning that the sound outlet is not eccentrically set and is located at the center of the corresponding surface of the first housing 110.

[0218] As shown in Figure 27, in the range of 1kHz-10kHz, the sound pressure level corresponding to the resonance peak of curve L444 is higher than that of other curves, indicating that when the sound outlet is located at the center of the corresponding side wall of the first housing 110, the sound pressure level of the sound output by the sound-emitting part 100 will be slightly higher.

[0219] Based on this, in some embodiments, referring to Figure 26A, the first sound outlet 112-1 and the second sound outlet 112-2 can adopt a single-hole structure, and the centroid of the first sound outlet 112-1 coincides with the center of the inner sidewall, and the centroid of the second sound outlet 112-2 coincides with the center of the outer sidewall, so that the sound outlet is located at the center of the corresponding sidewall of the first housing 110. That is, on a reference plane perpendicular to the vibration direction, the distance between the centroid of the projection of the second sound outlet and / or the centroid of the projection of the first sound outlet and the centroid of the projection of the corresponding sidewall of the first housing 110 is not greater than 5mm. This can increase the sound pressure level of the headphone output, improve the sensitivity of the headphone output, and enhance the user's listening experience.

[0220] As shown in Figure 27, comparing curves L441, L442, L443, and L444, the resonant frequencies corresponding to the high-frequency resonant peaks of the four curves are basically the same, indicating that the different placement of the sound outlet in the large-area concentrated opening form (i.e., the large-area single-hole form) has no effect on the position of the high-frequency peak of the headphones.

[0221] Based on this, in some embodiments, considering the structure of the earphone and other components, when the sound outlet may not be located at the center of the corresponding sidewall of the first housing 110, the first sound outlet 112-1 or the second sound outlet 112-2 can be adjusted to be off-center. Taking the setting position of the first sound outlet 112-1 as an example: Please refer to Figure 26B, the first sound outlet 112-1 can be off-center in the length direction relative to the center of the inner sidewall; Please refer to Figure 26C, the first sound outlet 112-1 can be off-center in the width direction relative to the center of the inner sidewall; the first sound outlet 112-1 can also be off-center in both the length and width directions relative to the center of the inner sidewall.

[0222] In some embodiments, to improve the sound output effect and / or enhance the sound leakage reduction effect of the headphones, the first acoustic cavity 111-1 and the second acoustic cavity 111-2 can be configured to be the same or similar. By configuring the first sound outlet 112-1 and the second sound outlet 112-2, the cancellation effect of the first sound output from the first sound outlet 112-1 and the second sound output from the second sound outlet 112-2 in the far field is enhanced, thereby improving the sound leakage reduction effect of the headphones in the far field; or, the cancellation effect of the first sound and the second sound in the near field is weakened, thereby improving the near field listening effect. For example, when the first sound outlet 112-1 and the second sound outlet 112-2 are the same size, opposite in position, and have the same configuration, and the first sound output from the first sound outlet 112-1 and the second sound output from the second sound outlet 112-2 have opposite phases but the same amplitude, the cancellation effect of the first sound and the second sound in the far field can be enhanced, thereby improving the sound leakage reduction effect of the headphones. For example, the first sound outlet 112-1 is designed to point towards the user's ear canal opening, and the second sound outlet 112-2 is designed to be close to the user's ear canal opening. When the first sound output from the first sound outlet 112-1 is opposite in phase and has the same amplitude as the second sound output from the second sound outlet 112-2, the near-field cancellation effect of the first sound and the second sound can be reduced, thereby improving the near-field listening effect of the headphones.

[0223] Figures 28A and 28B are schematic diagrams showing different relative positions of the first and second sound outlets according to some embodiments of this specification. Figure 29 is a schematic diagram of the frequency response curves of the loudspeakers corresponding to the first and second sound outlets set at different positions according to some embodiments of this specification. In Figure 28A, the first sound outlet 112-1 and the second sound outlet 112-2 are arranged opposite each other, both located at the center of their respective surfaces; in Figure 28B, the first sound outlet 112-1 and the second sound outlet 112-2 are eccentrically arranged in the length direction. It should be noted that Figure 29 is based on data measured under the condition that the first sound outlet 112-1 and the second sound outlet 112-2 are single holes with the same shape (e.g., the shorter side dimension is half the longer side dimension) and the same dimensions.

[0224] In Figure 29, curve L461 represents the frequency response curve at the first sound outlet 112-1 when the first sound outlet 112-1 and the second sound outlet 112-2 are directly opposite each other; curve L462 represents the frequency response curve at the second sound outlet 112-2 when the first sound outlet 112-1 and the second sound outlet 112-2 are directly opposite each other; curve L463 represents the frequency response curve at the first sound outlet 112-1 when the first sound outlet 112-1 and the second sound outlet 112-2 are misaligned; and curve L464 represents the frequency response curve at the second sound outlet 112-2 when the first sound outlet 112-1 and the second sound outlet 112-2 are misaligned. Curves L461, L462, L463, and L464 correspond to the same area for the first sound outlet 112-1 and the second sound outlet 112-2. As shown in Figure 29, compared with curves L461 and L462, the high-frequency resonance peaks of curves L463 and L464 are significantly shifted forward, from around 10kHz to around 8kHz.

[0225] Based on this, in some embodiments, referring to Figure 28A, the first sound outlet 112-1 and the second sound outlet 112-2 can adopt a single-hole structure, and the first sound outlet 112-1 and the second sound outlet 112-2 are arranged directly opposite each other. That is, on a reference plane perpendicular to the vibration direction, the distance between the centroid of the projection of the second sound outlet 112-2 and the centroid of the projection of the first sound outlet 112-1 is no greater than 5mm. In this way, when the first sound output from the first sound outlet 112-1 is out of phase and has the same amplitude as the second sound output from the second sound outlet 112-2, the first sound and the second sound can cancel each other out in the far field, improving the sound leakage reduction effect of the headphones. In other embodiments, referring to Figure 28B, the first sound outlet 112-1 and the second sound outlet 112-2 can also be staggered to meet the appearance requirements of the headphones or the sound-emitting part 100 or the structural design requirements of various components (e.g., improving the near-field listening effect of the headphones).

[0226] When the first sound outlet 112-1 and the second sound outlet 112-2 are misaligned, the size, shape, acoustic impedance, etc. of the first sound outlet 112-1 and the second sound outlet 112-2 can be designed to reduce the near-field cancellation of the first sound output from the first sound outlet 112-1 and the second sound output from the second sound outlet 112-1, thus ensuring the near-field listening effect of the headphones.

[0227] For example, an acoustic barrier, such as one or more of steel mesh, gauze, or waterproof and breathable membrane, can be provided at the second sound outlet 112-2. The acoustic barrier can be arranged inside the second acoustic cavity 111-2 and cover the second sound outlet 112-2. By reducing the sound pressure level of the sound output from the second sound outlet 112-2 through the acoustic barrier, it is possible to ensure a large output in the low frequency range and to prevent the sound output from the second sound outlet 112-2 from affecting the sound output from the first sound outlet 112-1, thereby ensuring the near-field listening effect of the headphones.

[0228] Due to limitations in the actual manufacturing process, as well as the design requirements of the headphones' components or appearance, the sizes of the first sound outlet 112-1 and the second sound outlet 112-2 may differ. This may affect the output of the headphones, thereby affecting the near-field listening effect and the active noise cancellation effect against larger ambient noise in open environments.

[0229] Figure 30 is a schematic diagram of first and second sound holes of different sizes according to some embodiments of this specification, and Figure 31 is a schematic diagram of the frequency response curves of loudspeakers corresponding to first and second sound holes of different sizes according to some embodiments of this specification. It should be noted that Figure 31 is based on data measured under the condition that the first sound hole 112-1 and the second sound hole 112-2 are single holes of the same shape (for example, the shorter side dimension of the sound hole is half the longer side dimension) and are directly opposite each other.

[0230] In Figure 31, curve L481 represents the frequency response curve at the first sound outlet 112-1 when the ratio of the long side dimension of both the first sound outlet 112-1 and the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.5; curve L482 represents the frequency response curve at the second sound outlet 112-2 when the ratio of the long side dimension of both the first sound outlet 112-1 and the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.5; curve L483 represents the frequency response curve at the second sound outlet 112-2 when the ratio of the long side dimension of both the first sound outlet 112-1 and the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.5; and curve L483 represents the frequency response curve at the second sound outlet 112-1 when the ratio of the long side dimension of both the first sound outlet 112-1 and the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.5. The frequency response curve at the first sound outlet 112-1 is shown when the ratio of the long side dimension of the corresponding surface of the first housing 110 to the long side dimension of the second sound outlet 112-2 is 0.5 and the ratio of the long side dimension of the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.2. Curve L484 represents the frequency response curve at the second sound outlet 112-2 when the ratio of the long side dimension of the first sound outlet 112-1 to the long side dimension of the corresponding surface of the first housing 110 is 0.5 and the ratio of the long side dimension of the second sound outlet 112-2 to the long side dimension of the corresponding surface of the first housing 110 is 0.2. The width dimension of the sound outlets with different long side dimensions is the same.

[0231] As shown in Figure 31, compared to curves L481 and L482, when the size of the first sound outlet 112-1 is larger than the size of the second sound outlet 112-2, the high-frequency resonance peak of curve L484 shifts significantly forward. The high-frequency resonance peaks of curves L481, L482, and L483 are located near 10kHz, while the high-frequency resonance peak of curve L484 is located near 5kHz. Curve L483 has a peak and valley near 6kHz, which affects the output of the sound-emitting part 100. When the size of the first sound outlet 112-1 is equal to the size of the second sound outlet 112-2, the trends of curves L481 and L482 are roughly the same, showing good consistency, indicating that the output effect of the sound-emitting part 100 is improved.

[0232] Based on this, in some embodiments, the size of the first sound outlet 112-1 and the size of the second sound outlet 112-2 are set to be the same, which helps to ensure that the sound-emitting part 100 has a flat frequency response curve and a phase curve with small changes in a wider frequency range, thereby enhancing the effect of active noise cancellation of the headphones in a wider frequency range.

[0233] In other embodiments, referring to Figure 30, when the dimensions of the first sound outlet 112-1 and the second sound outlet 112-2 need to be different to meet the design requirements and appearance requirements of various components of the headphones, the size of the first sound outlet 112-1 can be set to be larger than the size of the second sound outlet 112-2. For example, on a reference plane perpendicular to the vibration direction, the ratio of the projected area of ​​the second sound outlet 112-2 to the projected area of ​​the first sound outlet 112-1 is 0.4-2.5. Through the size design of the first sound outlet 112-1 and the second sound outlet 112-2, when the first sound output from the first sound outlet 112-1 can be opposite in phase and the second sound output from the second sound outlet 112-2, the cancellation effect of the first and second sounds in the far field is improved, thereby improving the sound leakage reduction effect of the headphones.

[0234] When the size of the first sound outlet 112-1 is different from that of the second sound outlet 112-2, an acoustic barrier can be installed at the second sound outlet 112-2. The acoustic barrier can be arranged inside the second acoustic cavity 111-2 and cover the second sound outlet 112-2. By reducing the sound pressure level of the output sound of the second sound outlet 112-2 through the acoustic barrier, it is possible to ensure a large output in the low frequency range and to prevent the output sound of the second sound outlet 112-2 from affecting the output sound of the first sound outlet 112-1, thereby ensuring the near-field listening effect of the headphones.

[0235] Figures 32A and 32B are schematic diagrams of acoustic apertures of different shapes according to some embodiments of this specification, and Figure 33 is a schematic diagram of the frequency response curves of loudspeakers corresponding to acoustic apertures of different shapes according to some embodiments of this specification. The sound outlet shown in Figure 32A is a single concentrated opening, and the sound outlet shown in Figure 32B is a single non-concentrated opening (e.g., an annular opening).

[0236] In Figure 33, curve L501 represents the frequency response curve of the sound-emitting part 100 corresponding to the sound outlet with a single concentrated opening as shown in Figure 32A, and curve L502 represents the frequency response curve of the sound-emitting part 100 corresponding to the sound outlet with a single non-concentrated opening (e.g., annular opening) as shown in Figure 32B.

[0237] It should be noted that the sound outlet represented by curve L501 has the same opening area (i.e., the same opening ratio) and the same opening position (i.e., the center position of the corresponding equivalent hole is the same). The opening ratio is calculated as the ratio of the opening area of ​​the sound outlet to the area of ​​the corresponding shell sidewall of the first shell 110, such as the ratio of the area of ​​the first sound outlet 112-1 to the area of ​​the inner wall surface. Both single concentrated opening and single non-concentrated opening can be understood as the corresponding sound outlet adopting a single hole structure.

[0238] As shown in Figure 33, compared to curve L501, the high-frequency resonance peak of curve L502 shifts to the right, indicating that the design of a single non-concentrated opening allows the resonant frequency of the corresponding acoustic cavity to be located at a higher frequency. Therefore, in some embodiments, referring to Figure 32B, the first sound outlet 112-1 or the second sound outlet 112-2 can adopt a single-hole structure with a single non-concentrated opening. Compared to a single concentrated opening, this allows the peak resonant frequency of the sound output from the sound outlet to be located in a higher frequency band, which is more conducive to the headphones having a flatter acoustic output over a wider frequency range and improving the active noise cancellation effect of the headphones.

[0239] Figures 34A and 34B are schematic diagrams showing different numbers of acoustic holes according to some embodiments of this specification, and Figure 35 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different opening shapes and different numbers of acoustic holes according to some embodiments of this specification. The acoustic holes shown in Figure 34A are not single, concentrated openings, while the acoustic holes shown in Figure 34B are single, non-concentrated openings (e.g., annular openings). The total opening area of ​​the sound outlet holes shown in Figures 34A and 34B is the same, i.e., the opening ratio is the same.

[0240] In Figure 35, curve L521 represents the frequency response of the sound-emitting part 100 with a single concentrated opening and an opening ratio of 0.25; curve L522 represents the frequency response of the sound-emitting part 100 with a non-single concentrated opening, a large mesh opening, and an opening ratio of 0.2178, as shown in Figure 34A; and curve L523 represents the frequency response of the sound-emitting part 100 with a non-single concentrated opening, a small mesh opening, and an opening ratio of 0.1657, as shown in Figure 34B.

[0241] Referring to Figure 35, comparing curves L521, L522, and L523, as the size of a single sound outlet decreases and the number of sound outlets increases, the corresponding high-frequency resonance peaks of the curves gradually increase. Therefore, in some embodiments, the sound outlets (e.g., the first sound outlet 112-1) can adopt a non-single, concentrated opening distribution as shown in Figures 34A and 34B, that is, the sound outlets are a porous structure composed of multiple small holes arranged in an array; this not only allows the high-frequency peak of the speaker 120 to be positioned higher, but also significantly increases the effective area of ​​sound output, ensuring active noise reduction, while also meeting the appearance design requirements of the sound-emitting part 100 or headphones.

[0242] Please refer to Figure 35 and compare curves L521, L522, and L523. As the size of a single sound outlet decreases and the number of sound outlets increases, the corresponding curves show a decrease in the output sound pressure level at high frequencies. When the aperture ratio is constant, if the size of a single sound outlet is too small, although the total number of sound outlets can be increased, thus increasing the high-frequency resonance peak, it will also increase the acoustic impedance of the sound outlet, thereby affecting the output sound pressure level. Therefore, to ensure the sound pressure level of the headphone output, when the sound outlet (e.g., the first sound outlet 112-1) adopts a multi-hole structure that is not a single concentrated opening, i.e., when the sound outlet is a multi-hole structure composed of multiple small holes arranged in an array, the diameter of a single small hole can be no less than 0.2 mm.

[0243] Figures 36A-36F are schematic diagrams of sound outlets with different distributions of non-single concentrated openings according to some embodiments of this application. Specifically, Figure 36A shows sound outlets with non-single concentrated openings distributed on one side of the housing sidewall corresponding to the first housing 110 along the long axis, with a corresponding opening ratio of 0.15; Figure 36B shows sound outlets with non-single concentrated openings annularly distributed on one side of the housing sidewall corresponding to the first housing 110 along the long axis, with a corresponding opening ratio of 0.15; Figure 36C shows sound outlets with non-single concentrated openings annularly distributed across the entire surface of the housing sidewall corresponding to the first housing 110, with a corresponding opening ratio of 0.15; Figure 36D shows a ring of sound outlets with non-single concentrated openings. The sound outlet holes are distributed on one side of the shell sidewall corresponding to the first shell 110 along the long axis, and the corresponding shell sidewall is provided with pressure relief holes on the other side along the long axis. The opening ratio of the sound outlet hole is 0.15, and the opening ratio of the pressure relief hole is 0.0375. Figure 36E shows that the sound outlet holes, which are not a single concentrated opening, are distributed in the central area of ​​the shell sidewall corresponding to the first shell 110, with a corresponding opening ratio of 0.15. Figure 36F shows that the sound outlet holes, which are not a single concentrated opening, are distributed on the entire surface of the shell sidewall corresponding to the first shell 110, with a corresponding opening ratio of 0.30. At this time, the first sound outlet hole 112-1 and the second sound outlet hole 112-2 can be designed to be directly opposite each other or staggered.

[0244] Figure 37 is a schematic diagram of the frequency response curves of the sound-emitting parts corresponding to the non-single concentrated openings with different distributions shown in some embodiments according to this description. Among them, curve L541 corresponds to the non-single concentrated openings that are distributed in a ring on the entire surface of the corresponding side wall of the first housing 110, with an opening ratio of 0.15; curve L542 corresponds to the sound-emitting hole shown in Figure 36B; curve L543 corresponds to the full opening of the corresponding side wall of the first housing 110, with an opening ratio of 1; curve L544 corresponds to the sound-emitting hole shown in Figure 36D; curve L545 corresponds to the sound-emitting hole shown in Figure 36E; curve L546 corresponds to the sound-emitting hole shown in Figure 36F; and curve L547 corresponds to the speaker 120 without the first housing 110.

[0245] Please refer to Figure 37. Comparing curves L546 and L543, the positions of the high-frequency peaks are basically the same, both around 8.3kHz. Comparing curves L541, L542, L544, L545, and L543, the frequencies corresponding to the high-frequency peaks of curves L541, L542, L544, and L545 (with an aperture ratio of 0.15) are all lower than the frequencies corresponding to the high-frequency peaks of curve L513 (with an aperture ratio of 0.3). Comparing curves L541, L542, L544, and L545 (all with an aperture ratio of 0.15), the high-frequency peak of curve L544 is located near 8.3kHz, and has an additional resonance peak near 6.5kHz; the high-frequency peak of curve L541 is located near 8.3kHz, and has an additional resonance peak near 6.1kHz; the high-frequency peak of curve L545 is located near 7.1kHz; and the high-frequency peak of curve L542 is located near 6.5kHz. Among them, when the opening ratio of the sound outlet is 0.15, the high frequency peaks corresponding to curves L541, L542, L544 and L545 are all higher than 6kHz.

[0246] Based on this, in some embodiments, when the sound outlet is a porous structure composed of multiple small holes arranged in an array (i.e., when the sound outlet adopts a non-single centralized opening structure), in order to make the headphones have a flatter output over a wider frequency range, the opening ratio of the sound outlet can be no less than 0.1; it can also be understood that on a reference plane perpendicular to the thickness direction (vibration direction), the area ratio of the projection of the first sound outlet 112-1 or the second sound outlet 112-2 in the projection of the corresponding side wall (e.g., inner side wall or outer side wall) of the first housing 110 is no less than 10%.

[0247] For example, when the aperture ratio of the sound outlet is 0.15, the high-frequency peaks corresponding to curves L541, L542, L544, and L545 are all higher than 6kHz. In this case, the headphones have a relatively flat output over a wider frequency range, resulting in better active noise cancellation. Alternatively, the aperture ratio of the sound outlet can be no less than 0.3, which further allows the headphones to have a relatively flat output over an even wider frequency range, resulting in a high-frequency peak in the output frequency response higher than 8kHz.

[0248] When worn, the first sound outlet 112-1 is located on the side closer to the external auditory canal 11. Due to limitations such as the opening size of the first sound outlet 112-1 and the coverage area relative to the first acoustic cavity 111-1, some of the sound generated by the speaker 120 (specifically, the first diaphragm 121-1) in the first acoustic cavity 111-1 will be obstructed by the shell sidewall of the first shell 110 (e.g., the part of the inner sidewall where the first sound outlet 112-1 is not opened) and cannot be directly output through the first sound outlet 112-1. As a result, a standing wave will be formed in the first acoustic cavity 111-1. This will cause the peak resonant frequency of the second resonant peak to shift forward (i.e., shift to the lower frequency band), affecting the effect of active noise cancellation of the headphones in a wider frequency range.

[0249] Therefore, in some embodiments, referring to Figures 36D and 38, a tuning hole 113-3 is also provided through the inner sidewall, which is connected to the first acoustic cavity 111-1. Based on the connection between the first sound outlet 112-1 and the tuning hole 113-3 and the first acoustic cavity 111-1, the peak resonant frequency of the second resonant peak of the sound output to the outside of the first housing 110 through the tuning hole 113-3 can be adjusted. For example, the peak resonant frequency of the second resonant peak is not less than 1kHz. At this time, the first sound outlet 112-1 can be a single-hole structure (e.g., a single concentrated opening structure) or a multi-hole structure (i.e., a non-single concentrated opening structure).

[0250] Specifically, most of the sound generated by the speaker 120 within the first acoustic cavity 111-1 is output through the first sound outlet 112-1, while a small portion of the sound is output through the tuning port 113-3. This minimizes the formation of standing waves within the first acoustic cavity 111-1, allowing the peak resonant frequency of the second resonant peak of the frequency response curve of the sound output from the first sound outlet 112-1 to shift as high as possible. This adjustment of the peak resonant frequency ultimately results in a flatter output across a wider frequency range for the headphones, facilitating active noise cancellation over a wider frequency range. Simultaneously, it also enhances the sound pressure level of the sound output from the first sound outlet 112-1, ensuring a superior listening experience for the user.

[0251] Figure 38 is a schematic diagram of the relative positions between the first sound outlet and the tuning hole according to some embodiments of this specification. Figure 39 is a schematic diagram of the frequency response curves of the sound-emitting part corresponding to different distances between any two holes or any hole and the boundary of the acoustic cavity in Figure 38. Figure 40 is a schematic diagram of the frequency response curves of the sound-emitting part corresponding to different area ratios of the first sound outlet and the tuning hole in Figure 38.

[0252] Considering the different relative positions between the tuning port 113-3 and the first sound outlet 112-1, it may affect the output of the loudspeaker 120 or the position of the peak resonant frequency. Referring to Figure 38, taking an example where both the first sound outlet 112-1 and the tuning port 113-3 employ a multi-hole structure, L1-X is defined as the minimum distance between any two holes, and L2-X is defined as the minimum distance from the boundary of the first acoustic cavity 111-1 to any hole. It should be noted that the minimum distance here refers to the distance between the contour edges of any hole, or the distance from the contour edge of any hole to the boundary of the acoustic cavity.

[0253] Please refer to Figure 39. The horizontal axis LM is either L1-X or L2-X (that is, LM is the minimum distance between any two holes or the minimum distance between the boundary of the first acoustic cavity 111-1 and any hole).

[0254] As shown in Figure 39, the high-frequency peak corresponding to LM = 1.3mm is 9.5kHz, LM = 2.1mm is 9.25kHz, LM = 2.7mm is 9kHz, LM = 3.4mm is 8.75kHz, LM = 4mm is 7.75kHz, LM = 6mm is 7.5kHz, LM = 8mm is 6.7kHz, LM = 10mm is 5.8kHz, LM = 12mm is 4.5kHz, and LM = 14mm is 3.65kHz. With the increase of LM, the corresponding high-frequency peaks shift forward, which means that the opening area decreases accordingly, resulting in a decrease in the sound pressure level output from the inner wall side. When LM = 14mm, compared to other smaller LMs, the sound pressure level at 1kHz drops to 3dB, which is acceptable.

[0255] Therefore, in some embodiments, the minimum distance between any two holes or the minimum distance from the boundary of the first acoustic cavity 111-1 to any hole can be set to no more than 14 mm; it can also be understood that the minimum distance between the first sound outlet hole 112-1 and the tuning hole 113-3 is no more than 14 mm, the minimum distance from the boundary of the first acoustic cavity 111-1 to the first sound outlet hole 112-1 is no more than 14 mm, and the minimum distance from the boundary of the first acoustic cavity 111-1 to the tuning hole 113-3 is no more than 14 mm. It can also be understood that when the first sound outlet hole 112-1 and / or the tuning hole 113-3 is a porous structure composed of multiple small holes arranged in an array, the minimum distance between any two adjacent small holes is no more than 14 mm.

[0256] In this way, the sound output from the first sound outlet 112-1 can have a relatively flat phase curve at least in the frequency range below 1kHz, thereby ensuring that the headphones have a relatively flat output over a wider frequency range, which is beneficial for active noise cancellation in the headphones over a wider frequency range. In addition, as described in the aforementioned embodiments, the aperture of each small hole can be set to not less than 0.2mm.

[0257] Furthermore, in some embodiments, any of the aforementioned minimum distances can be set to no more than 10mm, no more than 8mm, no more than 6mm, or no more than 3.4mm, etc. For example, when the minimum distance is 10mm, the peak resonant frequency of the second resonant peak can be adjusted to 5.8kHz; when the minimum distance is 8mm, the peak resonant frequency of the second resonant peak can be adjusted to 6.7kHz; when the minimum distance is 6mm, the peak resonant frequency of the second resonant peak can be adjusted to 7.5kHz; and when the minimum distance is 3.4mm, the peak resonant frequency of the second resonant peak can be adjusted to 8.75kHz. Thus, by selecting and setting the minimum distance, the peak resonant frequency of the second resonant peak can be shifted as high as possible, further expanding the width of the flat region of the frequency response curve, enabling the headphones to achieve active noise cancellation over a wider frequency range.

[0258] In some embodiments, the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet hole 112-1 can be set to less than 23%. Specifically, on a reference plane perpendicular to the thickness direction, the total projected area of ​​the first sound outlet hole 112-1 on the reference plane is defined as S1, the total projected area of ​​the tuning hole 113-3 on the reference plane is defined as S2, and the ratio of the total projected area S1 of the tuning hole 113-3 to the total projected area S1 of the first sound outlet hole 112-1 is defined as SS.

[0259] As shown in Figure 40, as SS gradually increases, the high-frequency peak gradually shifts to the back, and the sound pressure level of the output sound gradually decreases. The increase of SS means that the opening area of ​​the tuning hole 113-3 increases, which can effectively achieve the pressure relief effect, thereby causing the high-frequency peak to shift to the back. However, at the same time, due to the increase in the opening area of ​​the tuning hole 113-3, the sound leakage through the tuning hole 113-3 also increases, thereby reducing the sound pressure level of the sound output through the first sound outlet 112-1. As can be seen from Figure 40, when SS is from 0% (i.e., no tuning hole 113-3 is set) to 22.7%, the high-frequency peak shifts from 8.5kHz to 9.75kHz, and the sound pressure level of the output sound decreases by 1dB, which is within an acceptable range.

[0260] Therefore, setting the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet hole 112-1 to less than 23% can effectively prevent excessive sound leakage from the tuning hole 113-3 due to the excessively large opening or area ratio of the tuning hole 113-3, thereby causing a decrease in the sound pressure level or volume of the first sound outlet hole 112-1.

[0261] For example, in some embodiments, the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet 112-1 is set to 22.7%, thereby adjusting the peak resonant frequency of the second resonant peak to about 9.75kHz, further expanding the width of the flat area of ​​the frequency response curve of the sound output through the first sound outlet 112-1, and enabling the headphones to perform active noise cancellation in a wider frequency range.

[0262] In some embodiments, referring to Figure 38, when worn, the tuning port 113-3 is located further away from the external auditory canal 11 than the first sound outlet 112-1. In open-back applications, since the ambient noise received by the user's external auditory canal 11 is relatively large, improving the output performance of the headphones helps the headphones actively reduce ambient noise. Therefore, by setting the tuning port 113-3 at a position further away from the external auditory canal 11 than the first sound outlet 112-1, the sound output through the tuning port 113-3 and the sound output through the first sound outlet 112-1 can cancel each other out in the far field, thereby reducing sound leakage and ensuring the user's listening experience.

[0263] For example, on a reference plane perpendicular to the thickness direction, the length of the projection of the first acoustic cavity 111-1 along its major axis is not less than its width along its minor axis. For instance, the projected shape of the first acoustic cavity 111-1 can be a rectangle with a length greater than its width, or a square or circle with a length equal to its width. The projection of the first acoustic cavity 111-1 on the reference plane (e.g., the area shown by the dashed box in Figure 38) is divided along its length into a first region and a second region (e.g., the two regions separated by the dashed arrows in Figure 38). The ratio of the length of the first region along its major axis to the length of the projection of the first acoustic cavity along its major axis can be set to less than 40%, for example, 38.3%. The projection of the tuning hole 113-3 on the reference plane is located within the first region, and the projection of the first sound outlet hole 112-1 on the reference plane is located within the second region.

[0264] Thus, by placing the tuning hole 113-3 and the first sound outlet hole 112-1 in different areas of the inner wall corresponding to the first acoustic cavity 111-1, it is possible to ensure that the tuning hole 113-3 is located further away from the external auditory canal than the first sound outlet hole 112-1 when the tuning hole 113-3 is an array of small holes or a large area of ​​concentrated openings and is close to the first sound outlet hole 112-1, so that the tuning hole 113-3 and the first sound outlet hole 112-1 can be distinguished. For example, in the length or diameter direction of the first acoustic cavity 111-1, the holes in the area from the boundary of the first acoustic cavity 111-1 to a proportion of 38.3% can be regarded as the tuning hole 113-3.

[0265] It should be noted that the dashed box in Figure 38 represents the projection boundary of the first acoustic cavity 111-1 on the reference plane; the dashed arrow in Figure 38 represents the approximate boundary between the first region and the second region in the projection shape of the first acoustic cavity 111-1, wherein the region to the left of the dashed arrow represents the first region, and the region to the right of the dashed arrow represents the second region.

[0266] In some embodiments, referring to Figure 38, when the first sound outlet 112-1 is a porous structure composed of multiple small holes arranged in an array, the diameter of the small holes located in the area of ​​the inner wall directly opposite the external auditory canal 11 in the wearing state is set to be larger than the diameter of the small holes located in other areas of the inner wall. For example, among the multiple small holes of the sound outlet 112-1, the diameter of the small holes near the boundary of the first acoustic cavity 111-1 and the tuning hole 113-3 is smaller than the diameter of the small holes in other positions. In this way, by differentiating the diameters of the multiple small holes in the first sound outlet 112-1, the sound pressure level of the sound output by the headphones directly opposite the external auditory canal 11 can be improved, thereby ensuring the user's listening effect.

[0267] As described in some of the embodiments above, by providing an acoustic barrier at the second sound outlet 112-2, the sound pressure level of the sound output from the second sound outlet 112-2 can be reduced, creating peak-valley suppression of the high-frequency resonance peak. This ensures that the headphones have a large output in the low-frequency range while preventing the sound output from the second sound outlet 112-2 from affecting the sound output from the first sound outlet 112-1, thus ensuring the near-field listening effect of the headphones. In some embodiments, an acoustic barrier can also be provided at the first sound outlet 112-1. For example, the acoustic barrier can be arranged inside the first acoustic cavity 111-2 and cover the first sound outlet 112-1 and the tuning port 113-3. For ease of distinction and description, the acoustic resistive mesh at the second sound outlet 112-2 is defined as the second acoustic resistive mesh, and the acoustic resistive mesh at the first sound outlet 112-1 is defined as the first acoustic resistive mesh. The acoustic impedance of the first acoustic resistive mesh is set to be less than that of the second acoustic resistive mesh. For example, the ratio of the acoustic impedance of the second acoustic resistive mesh to that of the first acoustic resistive mesh is not less than 10 (e.g., the acoustic impedance of the first acoustic resistive mesh is less than 10 Rayles, and the acoustic impedance of the second acoustic resistive mesh is greater than 700 Rayles).

[0268] Therefore, based on the characteristic of the low acoustic impedance of the first acoustic barrier, the impact on the sound output of the first sound outlet 112-1 can be minimized, ensuring the sound output effect of the sound-emitting part 100 on the side close to the external auditory canal 11. Furthermore, the first and second acoustic barriers can play a good role in dustproofing and waterproofing in the sound-emitting part 100.

[0269] In some embodiments, as described above, in order to reduce the resonant frequency of the first resonant peak, the K values ​​of the first diaphragm 121-1 and the second diaphragm 121-2 can be set to a lower value. At this time, in order to ensure the output stability of the loudspeaker 120, reduce the vibration modes, and improve the vibration consistency of the first diaphragm 121-1 and the second diaphragm 121-2, the first diaphragm 121-1 and the second diaphragm 121-2 can be directly connected by a connector (e.g., a first connector), or indirectly connected by a voice coil assembly 123 and a connector (e.g., a first voice coil, a second connector, and a second voice coil).

[0270] Figure 41 is a schematic diagram of the internal structure of a loudspeaker according to some embodiments of this specification; Figure 42 is another schematic diagram of the internal structure of a loudspeaker according to some embodiments of this specification; Figure 43A is an exploded view of a loudspeaker according to some embodiments of this specification; and Figure 43B is another exploded view of a loudspeaker according to some embodiments of this specification.

[0271] Referring to Figures 41 and 42, in some embodiments, the voice coil assembly 123 includes only a first voice coil 123-1, which is configured to simultaneously drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously in the same direction. In some embodiments, the magnetic circuit assembly 122 may include a magnetic shield 1221 and an inner magnet 1222. The inner magnet 1222 may be disposed within the first voice coil 123-1. The magnetic shield 1221 and the inner magnet 1222 are spaced apart in a direction perpendicular to the vibration direction. A magnetic gap is formed between the sidewall of the magnetic shield 1221 and the outer side of the inner magnet 1222, and at least a portion of the first voice coil 123-1 extends into the magnetic gap. In some embodiments, the first voice coil 123-1 includes a first end located outside the magnetic gap (e.g., the upper end of the first voice coil 123-1 in FIG. 41) and a second end located inside the magnetic gap (e.g., the lower end of the first voice coil 123-1 in FIG. 41). The first end of the first voice coil 123-1 is connected to the first diaphragm 121-1, and the second end of the first voice coil 123-1 is connected to the second diaphragm 121-2.

[0272] Considering that if the size of the first voice coil 123-1 is too large, it may reduce the driving force of the first voice coil 123-1 and affect the output of the speaker 120. In some embodiments, in order to reduce the size of the first voice coil 123-1 and ensure the driving force of the first voice coil 123-1, the second end of the first voice coil 123-1 can be connected to the second diaphragm 121-2 through the first connector 124.

[0273] In some embodiments, as shown in FIG41, the first connector 124 includes an annular structure adapted to the first voice coil 123-1. The annular structure increases the connection area between the first connector 124 and the second diaphragm 121-2, ensuring the connection strength between them and simultaneously making the force exerted by the first connector 124 on the second diaphragm 121-2 more uniform, thus making the vibration of the second diaphragm 121-2 more stable. One end of the first connector 124 is connected to the first voice coil 123-1, and the other end is connected to the second diaphragm 121-2. In some embodiments, the bottom of the magnetic shield 1221 may have an annular notch through which the first connector 124 can pass, allowing the voice coil 123 to simultaneously drive both the first diaphragm 121-1 and the second diaphragm 121-2 located on both sides of the magnetic shield 1221. In some embodiments, to maintain the installation stability of the magnetic shield 1221, the first connector 124 may include a plurality of annularly distributed sub-connecting portions, the annulus being adapted to the first voice coil 123-1. The bottom of the magnetic shield 1221 is correspondingly provided with a plurality of annularly shaped notches.

[0274] Referring to Figures 42, 43A, and 43B, in some embodiments, the first connector 124 includes a sub-connecting portion and a connecting surface. One end of the sub-connecting portion is connected to the second end of the first voice coil 123-1, and the other end of the sub-connecting portion is connected to the connecting surface. The connecting surface is connected to the second diaphragm 121-2. By connecting the connecting surface to the second diaphragm 121-2, the driving force and vibration of the voice coil 123 can be better transmitted to the second diaphragm 121-2, making the vibration of the second diaphragm 121-2 more stable. This helps to improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce the distortion of the headphone output, improve the active noise cancellation effect of the headphone, and improve the output effect of the headphone.

[0275] Referring to Figure 43A, in some embodiments, the sub-connector may include multiple (e.g., four) symmetrically arranged strip structures to reduce the mass of the first connector 124, reduce the load on the first voice coil 123-1, and increase the driving force of the first voice coil 123-1, thereby improving the output of the speaker 120. When applied to open-back headphones, since the ambient noise received by the user's ear canal is relatively large, improving the output performance of the headphones helps the headphones to actively cancel out large ambient noise.

[0276] Referring to Figure 43B, in some embodiments, the sub-connecting portion may include two plate-like structures to enhance the structural strength of the first connector 124, enhance the connection strength between the connecting surface and the first voice coil 123-1, enhance the vibration stability of the second diaphragm 121-1, improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce the distortion of the headphone output, improve the active noise cancellation effect of the headphone, and improve the output effect of the headphone.

[0277] In some embodiments, the loudspeaker 120 has a long side along the major axis of the sound-emitting portion 100 and a short side along the minor axis of the sound-emitting portion 100. In some embodiments, a plate-like structure may be disposed between the short side of the connecting surface and the short side of the first voice coil 123-1.

[0278] In some embodiments, by reducing the mass of the first connector 124, the load on the first voice coil 123-1 can be reduced, the driving force of the first voice coil 123-1 can be increased, the output of the speaker 120 can be increased, and thus the output performance of the headphones can be improved, thereby improving the active noise cancellation performance of the headphones against large ambient noise. In some embodiments, in order to ensure the connection stability between the first connector 124 and the second diaphragm 121-2 while reducing the mass of the first connector 124, thereby improving the active noise cancellation effect of the headphones, the connection surface of the first connector 124 can be hollowed out.

[0279] Because the first voice coil 123-1 simultaneously drives both the first diaphragm 121-1 and the second diaphragm 121-2, the load on the first voice coil 123-1 increases, resulting in a decrease in the output of the speaker 120. This may affect the active noise cancellation effect of the headphones on louder ambient noise. In some embodiments, to ensure the output of the speaker 120 and improve the active noise cancellation effect of the headphones on louder ambient noise, the magnetic circuit assembly 122 can be designed to increase the magnetic field strength of the magnetic circuit assembly 122, thereby increasing the driving force of the first voice coil 123-1, thus increasing the output of the speaker 120 and improving the active noise cancellation effect of the headphones on louder ambient noise.

[0280] Figures 44A-46B are schematic diagrams of different structures of loudspeakers according to some embodiments of this specification.

[0281] Referring to Figures 44A and 44B, in some embodiments, while keeping the thickness of the magnetic shield 1221 constant, the size of the inner magnet 1222 can be increased to increase the magnetic field strength, thereby increasing the driving force of the first voice coil 123-1. The thickness of the magnetic shield 1221 refers to the thickness of its bottom wall or side wall. Specifically, the thickness of the bottom wall of the magnetic shield 1221 refers to its dimension in the vibration direction. The thickness of the side wall of the magnetic shield 1221 refers to its thickness in the corresponding minor axis or major axis direction. For example, in Figures 44A and 44B, the thickness of the magnetic shield 1221 is 0.7 mm. Compared to Figure 44A, the size of the inner magnet 1222 in Figure 44B is increased to increase the driving force of the first voice coil 123-1, improve the output of the speaker 120, and enhance the active noise cancellation effect of the headphones against larger ambient noise.

[0282] In order to make the inner magnet 1222 have a larger size, increase the driving force of the first voice coil 123-1, improve the output of the speaker 120, and improve the active noise cancellation effect of the headphones against large ambient noise, in some embodiments, the ratio of the size of the inner magnet 1222 to the side wall thickness of the magnetic shield 1221 can be 5-72.5.

[0283] To avoid excessively large headphone dimensions, the size of the inner magnet 1222 should not be too large when the thickness of the magnetic shield 1221 remains constant (e.g., the thickness of the magnetic shield 1221 is 0.7 mm). In some embodiments, the ratio of the size of the inner magnet 1222 to the sidewall thickness of the magnetic shield 1221 can be 11.4-120 in the short-axis or long-axis direction. In some embodiments, to further increase the driving force of the first voice coil 123-1, enhance the output of the speaker 120, and improve the active noise cancellation effect of the headphones against larger ambient noise, the ratio of the size of the inner magnet 1222 to the sidewall thickness of the magnetic shield 1221 can be 12.8-60 in the short-axis or long-axis direction.

[0284] It should be noted that the ratio of the size of the inner magnet 1222 to the sidewall thickness of the magnetic shield 1221 refers to the ratio of the size of the inner magnet 1222 along its long axis to the sidewall thickness of the magnetic shield 1221 along its long axis, or the ratio of the size of the inner magnet 1222 along its short axis to the sidewall thickness of the magnetic shield 1221 along its short axis. When the magnetic shield 1221 has a "U"-shaped structure, and the sidewall is only included in the long axis or short axis direction, the ratio of the size of the inner magnet 1222 to the sidewall thickness of the magnetic shield 1221 refers to the ratio of the size of the inner magnet 1222 in the corresponding direction to the sidewall thickness of the magnetic shield 1221.

[0285] Referring to Figures 45A and 45B, in some embodiments, to avoid the magnetic circuit assembly 122 becoming too large and reducing the design space of the speaker 120, when the size of the magnetic circuit assembly 122 is fixed, the size of the magnetic shield 1221 is also fixed. In this case, the thickness of the magnetic shield 1221 can be reduced and the size of the inner magnet 1222 can be increased to increase the magnetic field strength, thereby increasing the driving force of the first voice coil 123-1, improving the output of the speaker 120, and enhancing the active noise cancellation effect of the headphones against larger ambient noise. For example, in Figures 45A and 45B, the size of the magnetic shield 1221 remains unchanged; compared to Figure 45A, the sidewall thickness of the magnetic shield 1221 in Figure 45B is reduced (e.g., from 0.7mm to 0.1mm), and the size of the inner magnet 1222 in Figure 45B is increased.

[0286] In some embodiments, the ratio of the size of the inner magnet 1222 to the size of the magnetic shield 1221 in the short-axis or long-axis direction can be 0.9-72.5 to increase the driving force of the first voice coil 123-1, improve the output of the speaker 120, and enhance the active noise cancellation effect of the headphones against larger ambient noise. The size of the magnetic shield 1221 refers to the distance between the outer surfaces of the opposing sidewalls of the magnetic shield 1221 (e.g., the distance between two opposing sidewalls of the magnetic shield 1221 along the long-axis direction, or the distance between two opposing sidewalls of the magnetic shield 1221 along the short-axis direction). When the magnetic shield 1221 has a U-shaped structure, and only includes sidewalls in the long-axis or short-axis direction, the size of the magnetic shield 1221 in the direction without sidewalls can be the distance between the two outer surfaces of the bottom wall in the direction without sidewalls. When the magnetic shield 1221 has a circular structure, the size of the magnetic shield 1221 can refer to the diameter of the circular structure. The ratio of the size of the inner magnet 1222 to the size of the magnetic shield 1221 refers to the ratio of the size of the inner magnet 1222 in the long axis direction to the size of the magnetic shield 1221 in the long axis direction, or the ratio of the size of the inner magnet 1222 in the short axis direction to the size of the magnetic shield 1221 in the short axis direction.

[0287] In some embodiments, to further increase the driving force of the first voice coil 123-1, the ratio of the size of the inner magnet 1222 to the width of the magnetic shield 1221 in the short axis or long axis direction can be 1.2-60. In some embodiments, to ensure the structural strength of the magnetic shield 1221, the thickness of the magnetic shield 1221 should not be too thin (for example, the thickness of the magnetic shield 1221 can be greater than 0.1 mm), and the ratio of the size of the inner magnet 1222 to the width of the magnetic shield 1221 in the short axis or long axis direction can be 1.4-30.

[0288] Please refer to Figures 45A and 46A. In order to further enhance the magnetic field strength, increase the driving force of the first voice coil 123-1, improve the output of the speaker 120, and enhance the active noise reduction effect of the headphones on larger ambient noise, in some embodiments, an external magnet 1223 can be provided on the side wall of the magnetic shield 1221, that is, the side wall of the magnetic shield 1221 may include an external magnet 1223.

[0289] Referring to Figures 46A and 46B, in some embodiments, to avoid the magnetic circuit assembly 122 becoming too large and reducing the design space of the speaker 120, while providing an outer magnet 1223 on the sidewall of the magnetic shield 1221, the size of the inner magnet 1222 can be increased and the size of the outer magnet 1223 can be decreased. For example, compared to Figure 46A, the thickness of the outer magnet 1223 in Figure 46B is reduced (e.g., from 0.7 mm to 0.1 mm), and the size of the inner magnet 1222 in Figure 46B is increased.

[0290] In some embodiments, the ratio of the thickness of the outer magnet 1223 to the size of the inner magnet 1222 can be 0.6-13.7 in the short axis or long axis direction to increase the driving force of the first voice coil 123-1, improve the output of the speaker 120, and enhance the active noise cancellation effect of the headphones against larger ambient noise. When the outer magnet 1223 is a ring structure, the thickness of the outer magnet 1223 refers to the difference between the outer diameter and the inner diameter of the ring. When the outer magnet 1223 is a split structure as shown in Figure 51, the thickness of the outer magnet 1223 refers to the distance between the inner surface of each part of the split structure facing the inner magnet 1222 and the outer surface facing away from the inner magnet 1222.

[0291] In some embodiments, due to manufacturing difficulties, the thickness of the outer magnet 1223 should not be too thin (for example, the thickness of the outer magnet 1223 can be not less than 0.5 mm). In the short axis direction or the long axis direction, the ratio of the thickness of the outer magnet 1223 to the size of the inner magnet 1222 can be 0.8-10. In some embodiments, if the thickness of the outer magnet 1223 is too thick, it may cause the sidewall of the magnetic shield 1221 on which the outer magnet 1223 is mounted to be too thick, resulting in the headphones being too heavy and affecting the user's wearing comfort. In order to improve the wearing comfort of the headphones, in the short axis direction or the long axis direction, the ratio of the thickness of the outer magnet 1223 to the size of the inner magnet 1222 can be 0.9-8.

[0292] Figure 47 is a schematic diagram of the driving force coefficient of a loudspeaker including internal magnets of different sizes according to some embodiments of this specification. The driving force coefficient of the loudspeaker 120 is the sum of the driving force coefficient of the first voice coil 123-1 and the driving force coefficient of the second voice coil 123-2. As shown in Figure 47, curve L... 61 This represents the driving force coefficient of the speaker 120 corresponding to different sizes of inner magnets 1222, assuming the thickness of the magnetic shield 1221 remains constant (e.g., the thickness of the magnetic shield 1221 is 0.7 mm); Curve L 62 This represents the driving force coefficient of the speaker 120 corresponding to different sizes of internal magnets 1222, given a fixed size of the magnetic circuit assembly 122 (e.g., the size of the speaker 120 is 16mm); Curve L 63 This indicates the driving force coefficient of the speaker 120 corresponding to different sizes of inner magnets 1222 when an outer magnet 1223 is provided on the side wall of the magnetic shield 1221 and the size of the magnetic circuit assembly 122 is fixed.

[0293] As shown in Figure 47, curve L 63 Located on curve L 61 With curve L 62 Above, that is, when the size of the inner magnet 1222 is the same, L 63 The corresponding speaker 120 has the highest driving force coefficient, indicating that placing the outer magnet 1223 on the side wall of the magnetic shield 1221 can effectively improve the driving force coefficient of the speaker 120. When the size of the inner magnet 1222 is small (e.g., less than 8mm), curve L... 61 With curve L 62 They roughly overlap, at this time L 61 The corresponding magnetic circuit component 122 has a small size change, similar to L. 62 For magnetic circuit components 122 of corresponding dimensions, the differences in size are not significant, and the differences in driving force coefficients are also small. When the size of the inner magnet 1222 is large (e.g., 8mm-13mm), curve L... 62 Located on curve L 61 Above and close, at this time L61 The corresponding magnetic circuit component 122 has a significant size variation, compared to L 62 The dimensions of magnetic circuit components 122 of corresponding sizes vary considerably. When the dimensions of the inner magnets 1222 are the same, L 61 The driving force coefficient of the corresponding speaker 120 is relatively small.

[0294] In summary, by setting the outer magnet 1223 and increasing the size of the inner magnet 1222, the driving force coefficient of the speaker 120 can be increased, the output of the speaker 120 can be increased, and the active noise cancellation effect of the headphones on large ambient noise can be improved.

[0295] Figure 48 is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification.

[0296] Referring to Figure 48, in some embodiments, the first diaphragm 121-1 can be connected to the first voice coil 123-1, and the first diaphragm 121-1 and the second diaphragm 121-2 are connected by a second connector 126. In the vibration direction of the first diaphragm 121-1 and the second diaphragm 121-2, the magnetic circuit assembly 122 has a through hole, and the second diaphragm 121-2 is disposed at the end of the through hole. When the first voice coil 123-1 drives the first diaphragm 121-1 to vibrate, the first diaphragm 121-1 drives the second diaphragm 121-2 to vibrate synchronously through the second connector 126. By placing the second diaphragm 121-2 in the through hole structure, the thickness of the speaker 120 can be effectively reduced, the design flexibility of the speaker 120 can be improved, and the wearing comfort of the headphones can be enhanced.

[0297] In some embodiments, the second diaphragm 121-2 may be disposed at the end of the through hole near the first diaphragm 121-1 to reduce the size of the second connector 126, reduce the mass of the second connector 126, reduce the load on the first voice coil 123-1, increase the driving force of the first voice coil 123-1, increase the output of the speaker 120, thereby improving the output performance of the headphones and enhancing the active noise cancellation effect of the headphones against larger ambient noise.

[0298] Figure 49 is another exemplary internal structure schematic diagram of a loudspeaker according to some embodiments of this specification, Figure 50 is another internal structure schematic diagram of the loudspeaker shown in Figure 49 from another perspective, and Figure 51 is an exploded schematic diagram of the loudspeaker shown in Figure 49.

[0299] Referring to Figure 49, in some embodiments, the voice coil assembly 123 includes a first voice coil 123-1 and a second voice coil 123-2 arranged along the vibration direction. A first diaphragm 121-1 is connected to the first voice coil 123-1, and a second diaphragm 121-2 is connected to the second voice coil 123-2. The first voice coil 123-1 and the second voice coil 123-2 respectively drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously in the same direction.

[0300] In some embodiments, compared to the case where the voice coil assembly 123 includes only the first voice coil 123-1, when the voice coil assembly 123 includes both the first voice coil 123-1 and the second voice coil 123-2, the voice coil assembly 123 can make fuller use of the magnetic gap, thereby increasing the driving force of the voice coil assembly 123, increasing the output of the speaker 120, improving the sound output effect of the headphones, and improving the active noise cancellation effect of the headphones against large ambient noise.

[0301] Referring to Figures 49, 50, and 51, in some embodiments, the first diaphragm 121-1 and the second diaphragm 121-2 can be connected by a second connector 126 to improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce the distortion of the headphone output, improve the active noise cancellation effect of the headphone, and improve the output effect of the headphone.

[0302] In some embodiments, the magnetic circuit assembly 122 is provided with a through hole that penetrates the inner magnet 1222, the first magnetic plate 1224 at the upper end of the inner magnet 1222, and the bottom wall of the magnetic cover 1221 at the lower end of the inner magnet 1222. The second connector 126 is disposed in the through hole, thereby connecting the first diaphragm 121-1 and the second diaphragm 121-2.

[0303] In some embodiments, the through-hole configuration can further ensure that the gas in the common cavity 111-3 between the first diaphragm 121-1 and the second diaphragm 121-2 can move back and forth as an accompanying mass with the vibration of the two diaphragms when the first diaphragm 121-1 and the second diaphragm 121-2 vibrate, thereby minimizing the compression of the common cavity 111-3 by the two diaphragms, which would lead to frequency response peaks and valleys, improve the output quality of the headphones, and thus improve the active noise cancellation effect of the headphones.

[0304] In some embodiments, the second connector 126 needs to have high deformation resistance to minimize its own deformation while ensuring the connection between the first diaphragm 121-1 and the second diaphragm 121-2, thereby improving the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reducing headphone output distortion, improving the active noise cancellation effect of the headphones, and enhancing the overall headphone output performance. In some embodiments, the Young's modulus of the material of the second connector 126 can be 100MPa-150MPa. In some embodiments, to further improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, the Young's modulus of the material of the second connector 126 can be 110MPa-140MPa.

[0305] To improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce headphone output distortion, and enhance the active noise cancellation and overall headphone performance, the contact areas between the two ends of the second connector 126 and the first and second diaphragms 121-1 and 121-2 should not be too small to better transmit deformation and power between them. However, if the size of the second connector 126 is too large, it will result in an excessively large through-hole in the magnetic circuit assembly 122, affecting the driving force coefficient of the speaker 120, its output, and the active noise cancellation performance of the headphone. In some embodiments, to ensure that the speaker 120 has a large driving force coefficient while improving the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, the size of the second connector 126 can be designed based on the size of the magnetic circuit assembly. For example, the size of the second connector 126 can be 3.4mm * 1.4mm * 4.7mm.

[0306] To avoid placing excessive load on the first diaphragm 121-1 and the second diaphragm 121-2 due to the second connector 126, and to ensure the driving force coefficient of the speaker 120 and improve the active noise cancellation effect of the headphones, the mass of the second connector 126 should be relatively small. That is, given a fixed size, the density of the second connector 126 should not be too high. In some embodiments, to reduce the load on the first diaphragm 121-1 and the second diaphragm 121-2, the density of the second connector 126 can be 100 kg / m³. 3 -140kg / m 3 .

[0307] Figure 52 is a schematic diagram of the driving force coefficient of a loudspeaker corresponding to different sizes of through holes according to some embodiments of this specification. In some embodiments, while keeping the size of the second connector 126 unchanged, the driving force coefficient of the loudspeaker 120 shown in Figure 52 is measured when the through hole sizes are 0mm*0mm, 2mm*1mm, 4mm*2mm, 5mm*2.5mm, 6mm*3mm, and 10mm*5mm. A through hole size of 0mm*0mm indicates that no through hole is provided. In this case, it can be considered that the first diaphragm 121-1 and the second diaphragm 121-2 are not connected through the second connector 126, and there is no direct connection between the first diaphragm 121-1 and the second diaphragm 121-2 (for example, as shown in Figure 61A).

[0308] Referring to Figure 52, the larger the through-hole size, the smaller the driving force coefficient of the speaker 120. Taking the driving force coefficient of the speaker 120 when the through-hole size is 0mm*0mm as the benchmark; when the through-hole size is 2mm*1mm, the effect on the driving force coefficient of the speaker 120 is negligible; when the through-hole size is 4mm*2mm, the driving force coefficient of the speaker 120 decreases by 0.1, a small decrease; when the through-hole size is 6mm*3mm, the driving force coefficient of the speaker 120 decreases by 0.15.

[0309] On the other hand, since the second connector 126 passes through the through hole, the size of the through hole also affects the size of the second connector 126. If the size of the through hole 126 is too small, the size of the second connector 126 may be too small, resulting in insufficient connection strength and making the second connector 126 prone to breakage or damage. Taking all factors into consideration, in order to ensure that the speaker 120 has a large driving force coefficient while the second connector 126 has appropriate dimensions, the length of the through hole can be 2mm-10mm, and the width can be 1mm-5mm.

[0310] Figure 53 is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification. Referring to Figure 53, in some embodiments, the voice coil assembly 123 includes a first voice coil 123-1 and a second voice coil 123-2 disposed along the vibration direction. A first diaphragm 121-1 is connected to the first voice coil 123-1, and a second diaphragm 121-2 is connected to the second voice coil 123-2. The first voice coil 123-1 and the second voice coil 123-2 respectively drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously in the same direction. The first voice coil 123-1 and the second voice coil 123-2 are connected by a third connector 127, so that the first diaphragm 121-1 and the second diaphragm 121-2 are indirectly connected.

[0311] Optionally, the magnetic circuit assembly 122 may be further provided with through holes. The through holes can further ensure that the gas in the common cavity 111-3 between the first diaphragm 121-1 and the second diaphragm 121-2 can move back and forth as an accompanying mass with the vibration of the two diaphragms, thereby minimizing the compression of the common cavity 111-3 by the two diaphragms, which would lead to frequency response peaks and valleys, improve the output quality of the headphones, and enhance the active noise cancellation effect of the headphones.

[0312] In some embodiments, while the first diaphragm 121-1 and the second diaphragm 121-2 are directly connected via the second connector 126, the first voice coil 123-1 and the second voice coil 123-2 can also be connected via the third connector 127. The third connector 127 can prevent relative displacement between the first voice coil 123-1 and the second voice coil 123-2, thereby further improving the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reducing distortion in the headphone output, improving the active noise cancellation effect of the headphones, and enhancing the overall output performance of the headphones.

[0313] Figure 54A is a schematic diagram of another exemplary structure of a loudspeaker according to some embodiments of this specification; Figure 54B is a schematic diagram of the loudspeaker shown in Figure 54A from another perspective; Figure 55 is a schematic diagram of another connection structure between the first voice coil and the second voice coil according to some embodiments of this specification; and Figure 56 is a schematic diagram of another exemplary structure of a loudspeaker according to some embodiments of this specification. Referring to Figures 54A-56, in some embodiments, the first voice coil 123-1 and the second voice coil 123-2 can be connected by a third connector 127, thereby achieving an indirect connection between the first diaphragm 121-1 and the second diaphragm 121-2, ensuring the vibration consistency of the first diaphragm 121-1 and the second diaphragm 121-2, reducing distortion in the headphone output, improving the active noise cancellation effect of the headphones, and enhancing the output effect of the headphones. Optionally, similar to the magnetic circuit assembly shown in Figure 53, the magnetic circuit assembly 122 can be further provided with through holes.

[0314] In some embodiments, the third connector 127 can be a sheet-like structure extending along the vibration direction, with the first voice coil 123-1 and the second voice coil 123-2 connected to the inner or outer side of the sheet-like structure, respectively. The sheet-like structure reduces the space occupied by the connection between the first voice coil 123-1 and the second voice coil 123-2, thereby preventing the speaker 120 from becoming too large. In some embodiments, the first voice coil 123-1 can be connected to the inner side of the sheet-like structure, and the second voice coil 123-2 can be connected to the inner side of the sheet-like structure; or, the first voice coil 123-1 can be connected to the inner side of the sheet-like structure, and the second voice coil 123-2 can be connected to the outer side of the sheet-like structure; or, the first voice coil 123-1 can be connected to the outer side of the sheet-like structure, and the second voice coil 123-2 can be connected to the inner side of the sheet-like structure; or, the first voice coil 123-1 can be connected to the outer side of the sheet-like structure, and the second voice coil 123-2 can be connected to the outer side of the sheet-like structure.

[0315] In some embodiments, the third connector 127 can be a bent structure. As shown in Figures 56A and 55, the bent structure can be a "Z"-shaped structure, including a first part connected to the first voice coil 123-1, a second part connected to the second voice coil 123-2, and a third part connecting the first part and the second part. The first part and the second part extend in parallel or approximately parallel directions, and the third part is perpendicular or approximately perpendicular to the first and second parts. Through the design of the first, second, and third parts, the bent structure has a certain dimension in the vibration direction and also a certain dimension in the direction perpendicular to the vibration direction, thus allowing the bent third connector 127 to be adapted to first voice coils 123-1 and second voice coils 123-2 of different sizes. The bent third connector 127 can be connected between the first voice coil 123-1 and the second voice coil 123-2 in the long axis direction or in the short axis direction. The smaller mass of the bent structure reduces the load on the first voice coil 123-1 and the second voice coil 123-2, increases the output of the speaker 120, and thus improves the active noise cancellation effect of the headphones on larger ambient noise in open-back wearing mode.

[0316] In some embodiments, the third connector 127 can also be a spacer structure, extending perpendicular to the vibration direction, as shown in Figure 56. The first voice coil 123-1 and the second voice coil 123-2 are respectively connected to the two ends of the spacer structure in the vibration direction. In this case, the first voice coil 123-1 and the second voice coil 123-2 can be connected and fixed to the spacer structure by clamping the spacer structure. The spacer structure can be applied to first voice coil 123-1 and second voice coil 123-2 of different sizes. The spacer structure has high strength and strong connection stability, which can further ensure the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce the distortion of the headphone output, improve the active noise cancellation effect of the headphone, and improve the output effect of the headphone. On the other hand, the limited thickness of the spacer structure in the vibration direction can prevent the size of the speaker 120 from being too large.

[0317] In some embodiments, the third connector 127 may include two sub-connectors, which are respectively connected to the first diaphragm 121-1 and the second diaphragm 121-2, and are interconnected. The sub-connectors enhance the design flexibility and applicability of the third connector 127.

[0318] Figure 57 is a schematic diagram of a skeleton according to some embodiments of this specification, and Figure 58 is another schematic diagram of a skeleton according to some embodiments of this specification.

[0319] Referring to Figures 57 and 58, in some embodiments, the first voice coil 123-1 and the second voice coil 123-2 can be connected by an annular frame 123-4. The frame 123-4 has high strength and strong connection stability, which can further ensure the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reduce the distortion of the headphone output, improve the active noise cancellation effect of the headphone, and improve the output effect of the headphone.

[0320] Referring to Figure 58, in some embodiments, the number of skeletons 123-4 can be one. The skeleton 123-4 may include an integrally formed first part and a second part. The first voice coil 123-1 can be disposed on the outer or inner periphery of the first part, and the second voice coil 123-2 can be disposed on the outer or inner periphery of the second part. For example, the first voice coil 123-1 can be disposed on the outer periphery of the first part, and the second voice coil 123-2 can be disposed on the outer periphery of the second part. Another example: the first voice coil 123-1 can be disposed on the outer periphery of the first part, and the second voice coil 123-2 can be disposed on the inner periphery of the second part. Yet another example: the first voice coil 123-1 can be disposed on the inner periphery of the first part, and the second voice coil 123-2 can be disposed on the outer periphery of the second part. Still another example: the first voice coil 123-1 can be disposed on the inner periphery of the first part, and the second voice coil 123-2 can be disposed on the inner periphery of the second part. The one-piece molded frame 123-4 can effectively prevent the voice coil assembly 123 from detaching from the frame 123-4 during vibration, thereby enhancing the structural stability and integrity of the voice coil assembly 123.

[0321] Referring to Figure 57, in some embodiments, there can be two skeletons 123-4. The two skeletons 123-4 can be connected by a connector (e.g., a third connector 127) or directly connected (e.g., bonded). The first voice coil 123-1 can be disposed on the outer or inner periphery of one of the skeletons 123-4, and the second voice coil 123-2 can be disposed on the outer or inner periphery of the other skeleton 123-4. For example, the first voice coil 123-1 can be disposed on the outer periphery of the first voice coil 123-1, and the second voice coil 123-2 can be disposed on the outer periphery of the second voice coil 123-2. Another example: the first voice coil 123-1 can be disposed on the outer periphery of the first voice coil 123-1, and the second voice coil 123-2 can be disposed on the inner periphery of the second voice coil 123-2. Yet another example: the first voice coil 123-1 can be disposed on the inner periphery of the first voice coil 123-1, and the second voice coil 123-2 can be disposed on the outer periphery of the second voice coil 123-2. For example, the first voice coil 123-1 can be located on the inner circumference of the first voice coil 123-1, and the second voice coil 123-2 can be located on the inner circumference of the second voice coil 123-2. The separate arrangement of the two frames 123-4 can improve the flexibility of the frame 123-4 arrangement.

[0322] In some embodiments, the skeleton 123-4 may be part of the third connector 127, and the first voice coil 123-1 and the second voice coil 123-2 are connected via the skeleton 123-4 of the third connector 127. For example, the third connector 127 may include a skeleton 123-4 comprising an integrally formed first part and a second part. As another example, the third connector 127 may include two skeletons 123-4, which can be connected by a sub-connecting portion of the third connector 127.

[0323] In some embodiments, the frame 123-4 and / or the third connector 127 may be made of aluminum alloy, or of low-density PMI (Polymethacrylimide) or PC (Polycarbonate), or a hybrid material (e.g., PC with added glass fiber or carbon fiber). By using these materials, the load on the first voice coil 123-1 and the second voice coil 123-2 can be reduced, which helps to increase the driving force coefficient of the speaker 120 and improve the active noise cancellation effect of the headphones in open-back wearing conditions with larger ambient noise.

[0324] In some embodiments, the first voice coil 123-1 and the second voice coil 123-2 may also be directly bonded together with glue.

[0325] By directly connecting the first diaphragm 121-1 to the second diaphragm 121-2 and / or directly connecting the first voice coil 123-1 to the second voice coil 123-2, the probability of separation between the first diaphragm 121-1 and the second diaphragm 121-2 can be further reduced, improving the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, reducing distortion in headphone output, improving the active noise cancellation effect of the headphones, and enhancing the overall output performance of the headphones. Conversely, directly connecting the first diaphragm 121-1 and the second diaphragm 121-2 via the second connector 126 can also reduce the precision required for alignment when connecting the first voice coil 123-1 and the second voice coil 123-2, thereby reducing operational difficulty.

[0326] In some embodiments, the first voice coil 123-1 and the second voice coil 123-2 may have an unequal diameter structure. For example, on a reference plane perpendicular to the vibration direction, there may be a gap between the orthographic projection of the first voice coil 123-1 and the orthographic projection of the second voice coil 123-2 in the long axis direction or in the short axis direction, so that there is a part that is connected to each other and another part that is separated from each other between the first voice coil 123-1 and the second voice coil 123-2. In this way, based on the existence of the gap between the two, a clearance channel 123-3 is formed between the first voice coil 123-1 and the second voice coil 123-2, which allows the magnetic circuit assembly 122 (e.g., the sidewall of the magnetic shield 1221) to pass through the voice coil assembly 123. It can also be understood that, based on a reference plane perpendicular to the vibration direction, the orthographic projection of the first voice coil 123-1 in the reference plane and the orthographic projection of the second voice coil 123-2 in the reference plane can be partially connected or partially overlapped, thereby forming an avoidance channel 123-3 at the separation point of the first voice coil 123-1 and the second voice coil 123-2.

[0327] In some embodiments, referring to FIG57, the outline shape of the loudspeaker 120 is non-circular, such as rectangular, elliptical, etc. In this case, the sidewalls of the first voice coil 123-1 and the second voice coil 123-2 parallel to the major axis can be defined as long sidewalls, and the sidewalls parallel to the minor axis can be defined as short sidewalls. The orthographic projection of the long sidewall of the first voice coil 123-1 on the reference plane is connected to or at least partially overlaps with the orthographic projection of the long sidewall of the second voice coil 123-2 on the reference plane, while the orthographic projection of the short sidewall of the first voice coil 123-1 on the reference plane is separate from the orthographic projection of the short sidewall of the second voice coil 123-2 on the reference plane. That is, the short side dimensions of the first voice coil 123-1 and the second voice coil 123-2 are equal in diameter, while the long side dimensions are unequal in diameter. In this way, a clearance channel 123-3 can be formed between the short sidewalls of the first voice coil 123-1 and the short sidewalls of the second voice coil 123-2. In some other embodiments, the short sides of the first voice coil 123-1 and the second voice coil 123-2 may be of unequal diameter, while the long sides may be of equal diameter. In still other embodiments, the short sides of the first voice coil 123-1 and the second voice coil 123-2 may also be of unequal diameter, while the long sides may also be of unequal diameter.

[0328] In some embodiments, the outline of the sound-emitting part 100 or the loudspeaker 120 is approximately circular. In this case, the first voice coil 123-1 and the second voice coil 123-2 can be connected by a third connector 127, so that the orthographic projection of the first voice coil 123-1 on the reference plane is a first ring, the orthographic projection of the second voice coil 123-2 on the reference plane is a second ring, and the first ring and the second ring have different diameters. The third connector 127 is used to achieve partial connection and partial separation between the first voice coil 123-1 and the second voice coil 123-2, thereby forming a clearance channel 123-3.

[0329] By setting the first voice coil 123-1 and the second voice coil 123-2 as unequal diameter structures with locally unequal dimensions, the clearance channel 123-3 formed between the first voice coil 123-1 and the second voice coil 123-2 can provide clearance space for the magnetic circuit assembly 122 (e.g., the side wall of the magnetic shield 1221). This is equivalent to placing the voice coil assembly 123 in the same magnetic gap of the magnetic circuit assembly 122. This not only enhances the stability of the magnetic circuit assembly 122 itself and supports the rapid assembly of the speaker 120, but also helps to reduce the assembly difficulty and cost, and avoids the voice coil assembly 123 from touching the magnetic circuit assembly 122 during movement and affecting the sound output. Meanwhile, the outer magnet 1223 adopts a ring structure surrounding the magnetic shield 1221 or the inner magnet 1222, which allows the magnetic circuit assembly 122 to have a larger design size. By increasing the volume of the magnet, the driving force of the voice coil assembly 123 can be increased, thereby improving the sound output performance of the speaker 120 and enhancing the active noise cancellation effect of the headphones in the open-fit mode.

[0330] In other embodiments, the first voice coil 123-1 and the second voice coil 123-2 may also have the same diameter. Specifically, on a reference plane perpendicular to the vibration direction, the orthographic projections of the first voice coil 123-1 and the second voice coil 123-2 coincide. In this case, on a reference plane parallel to the vibration direction, there is a gap in the vibration direction between the orthographic projections of the first voice coil 123-1 and the second voice coil 123-2, thereby forming a clearance channel 123-3 between them. In this case, the magnetic circuit assembly 122 (e.g., the extension at the top of the sidewall of the magnetic shield 1221 shown in Figures 51 and 54B) can pass through the clearance channel 123-3 in a direction perpendicular to the vibration direction. For example, the extension at the top of the side wall of the magnetic shield 1221 shown in Figures 51 and 54B can pass through the clearance channel 123-3 in a direction perpendicular to the vibration direction, and the two ends of the extension are connected to the side wall of the magnetic shield 1221 and the outer magnet 1223, respectively.

[0331] In some embodiments, the skeleton 123-4 can also form an obstacle avoidance channel 123-3, and the principle of forming the obstacle avoidance channel 123-3 is the same as that of the first voice coil 123-1 and the second voice coil 123-2.

[0332] Figure 59 is a schematic diagram of the frequency response curve of the loudspeaker shown in Figure 58. Taking the example where the size of the first voice coil 123-1 is smaller than that of the second voice coil 123-2, curve L... 321 This represents the output sound pressure level of the first diaphragm 121-1 corresponding to the smaller voice coil (first voice coil 123-1) when the first voice coil 123-1 and the second voice coil 123-2 are driven simultaneously; curve L 322 This represents the output sound pressure level of the second diaphragm 121-2 corresponding to the larger voice coil (second voice coil 123-2) when the first voice coil 123-1 and the second voice coil 123-2 are driven simultaneously; curve L 323 This indicates the output phase of the first diaphragm 121-1 corresponding to the smaller voice coil (first voice coil 123-1) when the first voice coil 123-1 and the second voice coil 123-2 are driven simultaneously; curve L 324 This indicates the output phase of the second diaphragm 121-2 corresponding to the large voice coil (second voice coil 123-2) when the first voice coil 123-1 and the second voice coil 123-2 are driven simultaneously.

[0333] In some embodiments, the data acquisition environment shown in Figure 59 is as follows: the speaker 120 is fixed (e.g., handheld, directly fixed via a fixed platform, fixed using a handheld device, etc.), a voltage excitation of 0.5Vrms is applied, and the frequency response and phase of the corresponding diaphragm are measured using a test microphone 5mm away from the corresponding diaphragm. When fixing the speaker 120, it is necessary to avoid obstructing the speaker 120 to prevent affecting the acquisition results.

[0334] As shown in Figure 59, curve L 321 With curve L 322 The frequency response is relatively flat in the 200Hz-10kHz range, without any peaks or valleys, indicating good vibration and output consistency between the first diaphragm 121-1 and the second diaphragm 121-2. (Curve L) 323 With curve L 324 The phase difference is consistently within 180° in the 200-10kHz range, indicating that the vibration phases of the first diaphragm 121-1 and the second diaphragm 121-2 are opposite, and their vibrations are well-coordinated. Within the 200Hz-10kHz frequency range, curve L... 323 or curve L 324 The phase changes are all no greater than 20°, indicating that the vibration phase consistency between the first diaphragm 121-1 and the second diaphragm 121-2 is good.

[0335] In summary, by adopting a structure with unequal diameters for the first voice coil 123-1 and the second voice coil 123-2, it is possible to ensure good vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, thereby reducing distortion in headphone output, improving the active noise cancellation effect of the headphones, and enhancing the overall output performance of the headphones.

[0336] Figure 60 is a schematic diagram of the structure of a magnetic shield according to some embodiments of this specification.

[0337] Referring to Figure 60, in some embodiments, the magnetic shield 1221 can be a U-shaped structure. Specifically, the magnetic shield 1221 includes a bottom wall 12211, an inner side wall 12212, and an extension 12213 disposed at the top end of the inner side wall 12212. The magnetic shield 1221 includes an inner side wall 12212 parallel to its minor axis, but does not have an inner side wall 12212 parallel to its major axis. The inner magnet 1222 is disposed on the bottom wall 12211, and the bottom wall 12211 and the inner side wall 12212 can support and fix the inner magnet 1222. The extension 12213 can be connected to the outer magnet 1223. The structure of the magnetic circuit component 122 with no connection on the long side and connection on the short side facilitates the formation of a strong and uniform magnetic field between the long side of the inner magnet 1222 and the long side of the outer magnet 1223. This allows the magnetic field to pass through the magnetic gap as much as possible, making full use of the magnetic field, effectively enhancing the driving force of the voice coil component 123, improving the sound output performance of the speaker 120, and enhancing the active noise cancellation effect of the headphones in the case of large ambient noise in the open-fit mode.

[0338] In some embodiments, the inner sidewall 12212 or the extension 12213 of the magnetic shield 1221 can pass through the clearance channel 123-3 so that the magnetic circuit assembly 122 extends out of the voice coil assembly 123, which facilitates the fixation of the magnetic circuit assembly 122.

[0339] In some embodiments, in order to improve the structural strength of the magnetic shield 1221, the connection bend between the inner sidewall 12212 and the bottom wall 12211, and the connection bend between the inner sidewall 12212 and the extension 12213 can be provided with rounded corners, and the bottom wall 12211 can be provided with reinforcing members.

[0340] In some embodiments, the inner sidewall 12212 may be hollowed out or made of a non-magnetic material to reduce the conduction of magnetic field lines in the vertical direction of the inner sidewall 12212, weaken the influence of magnetic short circuit of the inner sidewall 12212, reduce the influence on the voice coil assembly 123, enable the voice coil assembly 123 to have a larger driving force, improve the sound output performance of the speaker 120, and enhance the active noise cancellation effect of the headphones on large environmental noise in open-fit mode.

[0341] In some embodiments, the four corners of the bottom wall 12211 are provided with stepped structures. The stepped structures can further prevent the bottom wall 12211 of the magnetic shield 1221 from interfering with the third connector 127, giving the third connector 127 more room to move, thereby giving the voice coil assembly 123 more space to vibrate, improving the output performance of the speaker 120, and improving the active noise reduction effect of the headphones on large ambient noise in open-fit mode.

[0342] Figures 61A-61G are schematic diagrams of different exemplary structures of a loudspeaker according to some embodiments of this specification.

[0343] Referring to Figure 61A, in some embodiments, the voice coil assembly 123 includes a first voice coil 123-1 and a second voice coil 123-2 arranged along the vibration direction. A first diaphragm 121-1 is connected to the first voice coil 123-1, and a second diaphragm 121-2 is connected to the second voice coil 123-2. The first voice coil 123-1 and the second voice coil 123-2 respectively drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously in the same direction. The first diaphragm 121-1 and the second diaphragm 121-2 are not directly connected, nor are the first voice coil 123-1 and the second voice coil 123-2. The first voice coil 123-1 drives the first diaphragm 121-1 to vibrate independently, and the second voice coil 123-2 drives the second diaphragm 121-2 to vibrate synchronously in the same direction. This configuration simplifies the internal structure of the loudspeaker 120 and reduces manufacturing difficulty.

[0344] In some embodiments, in order to improve the output sound of the headphones, improve the listening effect of the headphones, and improve the active noise cancellation effect of the headphones against large ambient noise, the magnetic circuit component 122 can be designed to enhance the magnetic field strength of the magnetic circuit component 122 and increase the driving force of the voice coil component 123.

[0345] Referring to Figure 61A, in some embodiments, the magnetic shield 1221 may include a bottom wall 12211 and a side wall. The side wall may be a folded structure with an opening facing the bottom of the magnetic shield 1221. The folded structure includes an inner side wall 12212 and an outer side wall 12214 of the magnetic shield 1221. The bottom wall 12211 is disposed at the end of the inner side wall 12212 near the opening, and the inner magnet 1222 is disposed on the bottom wall 12211. The end of the inner side wall 12212 away from the opening and the end of the outer side wall 12214 away from the opening are connected by an extension 12213. A first magnetic gap is formed between the inner wall 12212 of the magnetic shield 1221 and the inner magnet 1222, and at least part of the first voice coil 123-1 is located within the first magnetic gap; a second magnetic gap is formed between the inner wall 12212 and the outer wall 12214 of the magnetic shield 1221, and at least part of the second voice coil 123-2 is located within the second magnetic gap.

[0346] Because the second voice coil 123-2 is far from the inner magnet 1222, the magnetic field strength near the second voice coil 123-2 is relatively small, and the second voice coil 123-2 may have insufficient driving force. In order to improve the driving force of the second voice coil 123-2, thereby improving the driving force of the speaker 120, improving the output of the speaker 120, and improving the active noise cancellation effect of the headphones to larger ambient noise, the magnetic circuit assembly 122 can be designed.

[0347] Referring to Figure 61B, in some embodiments, an outer magnet 1223 can be provided at the outer wall 12214 of the magnetic shield 1221 (i.e., the outer wall 12214 may include the outer magnet 1223) to increase the magnetic field strength near the second voice coil 123-2, thereby increasing the driving force of the second voice coil 123-2, increasing the driving force of the speaker 120, increasing the output of the speaker 120, and improving the active noise cancellation effect of the headphones against large ambient noise. At this time, a first magnetic gap is formed between the inner magnet 1222 and the inner wall 12212, and a second magnetic gap is formed between the outer magnet 1223 and the inner wall 12212. In some embodiments, the magnetization direction of the outer magnet 1223 can be the same as or opposite to the magnetization direction of the inner magnet 1222. For example, the N pole of the inner magnet 1222 can be located at the upper end, and the N pole of the outer magnet 1223 can be located at the upper end (as shown in Figure 61A). For example, the N pole of the inner magnet 1222 can be located at the upper end, and the N pole of the outer magnet 1223 can be located at the lower end (as shown in Figure 61G).

[0348] In some embodiments, when the magnetization directions of the inner magnet 1222 and the outer magnet 1223 are the same (e.g., the N poles are both located at the upper end as shown in FIG61A), the inner sidewall 12212 of the magnetic shield 1221 is subjected to the combined action of the inner magnet 1222 and the outer magnet 1223, and the inner sidewall 12212 exhibits magnetic field saturation, which limits the increase in magnetic field strength at the locations of the first voice coil 123-1 and the second voice coil 123-2, affects the driving force of the first voice coil 123-1 and the second voice coil 123-2, and affects the active noise cancellation effect of the headphones. In some embodiments, as shown in FIG61C, the size of the inner sidewall 12212 can be increased to avoid magnetic field saturation of the inner sidewall 12212 as much as possible, thereby increasing the magnetic field strength at the location of the first voice coil 123-1 and the second voice coil 123-2, thereby increasing the driving force of the speaker 120, increasing the output of the speaker 120, and improving the active noise cancellation effect of the headphones on large ambient noise. The magnetic circuit assembly 122 can be designed accordingly.

[0349] Referring to Figures 61B and 61C, in some embodiments, to avoid the magnetic circuit assembly 122 becoming too large, the size of the inner magnet 1222 can be reduced while keeping the size of the magnetic circuit assembly 122 unchanged (i.e., the size of the magnetic shield 1222 unchanged), thereby increasing the size of the inner sidewall 12212. In some embodiments, the ratio of the thickness of the inner sidewall 12212 to the size of the magnetic shield 1222 can be 0.05-0.16 in the short-axis or long-axis direction. In some embodiments, to further enhance the driving force of the speaker 120, the ratio of the thickness of the inner sidewall 12212 to the size of the magnetic shield 1222 can be 0.06-0.15 in the short-axis or long-axis direction. In some embodiments, while keeping the size of the magnetic circuit assembly 122 unchanged (i.e., the width of the magnetic shield 1222 unchanged), the thickness of the inner sidewall 12212 is negatively correlated with the size of the inner magnet 1222. For example, in either the minor or major axis direction, when the size of the magnetic shield 1222 is 16mm, the thickness of the inner sidewall 12212 can be 0.8mm-2.5mm; wherein, when the size of the inner magnet 1222 is greater than 4.7mm, the thickness of the inner sidewall 12212 can be 2mm-2.5mm; when the size of the inner magnet 1222 is greater than 5.7mm, the thickness of the inner sidewall 12212 can be 1.5mm-2.5mm; and when the size of the inner magnet 1222 is greater than 6.7mm, the thickness of the inner sidewall 12212 can be 1.2mm. The thickness of the inner wall 12212 can be 1.1mm-2.5mm when the radius of the inner magnet 1222 is greater than 7.7mm; when the radius of the inner magnet 1222 is greater than 8.7mm, the thickness of the inner wall 12212 can be 1mm-2mm; when the radius of the inner magnet 1222 is greater than 9.7mm, the thickness of the inner wall 12212 can be 0.8mm-1.6mm; when the radius of the inner magnet 1222 is greater than 10.7mm, the thickness of the inner wall 12212 can be 0.8mm-1.3mm.

[0350] In some embodiments, as shown in FIG61D, the outer magnet 1223 may also be disposed on the inner sidewall 12212 (i.e., the inner sidewall 12212 may include the outer magnet 1223) to avoid magnetic field saturation on the inner sidewall 12212, ensuring the magnetic field strength at the locations of the first voice coil 123-1 and the second voice coil 123-2, thereby increasing the driving force of the speaker 120, increasing the output of the speaker 120, and improving the active noise cancellation effect of the headphones on larger ambient noise. In this case, a first magnetic gap is formed between the inner magnet 1222 and the outer magnet 1223, and a second magnetic gap is formed between the outer magnet 1223 and the outer sidewall 12214. In some embodiments, the magnetization direction of the outer magnet 1223 may be the same as or opposite to the magnetization direction of the inner magnet 1222.

[0351] In some embodiments, as shown in FIG61E, in order to further enhance the magnetic field strength at the locations of the first voice coil 123-1 and the second voice coil 123-2, thereby enhancing the driving force of the speaker 120, increasing the output of the speaker 120, and improving the active noise cancellation effect of the headphones against larger ambient noise, the inner sidewall 12212 of the magnetic shield 1221 may be provided with a first outer magnet 1223-1, and the outer sidewall 12214 of the magnetic shield 1221 may be provided with a second outer magnet 1223-2. That is, the inner sidewall 12212 may include the first outer magnet 1223-1, and the outer sidewall 12214 may include the second outer magnet 1223-2. At this time, a first magnetic gap is formed between the inner magnet 1222 and the first outer magnet 1223-1, and a second magnetic gap is formed between the first outer magnet 1223-1 and the second outer magnet 1223-2. In some embodiments, the magnetization directions of the inner magnet 1222, the first outer magnet 1223-1, and the second outer magnet 1223-2 may be the same or opposite. For example, the magnetization directions of the inner magnet 1222 and the first outer magnet 1223-1 can be the same, and the magnetization directions of the inner magnet 1222 and the second outer magnet 1223-2 can be the same; or, the magnetization directions of the inner magnet 1222 and the first outer magnet 1223-1 can be the same, and the magnetization directions of the inner magnet 1222 and the second outer magnet 1223-2 can be opposite; or, the magnetization directions of the inner magnet 1222 and the first outer magnet 1223-1 can be opposite, and the magnetization directions of the inner magnet 1222 and the second outer magnet 1223-2 can be the same; or, the magnetization directions of the inner magnet 1222 and the first outer magnet 1223-1 can be opposite, and the magnetization directions of the inner magnet 1222 and the second outer magnet 1223-2 can be opposite.

[0352] Referring to Figure 61F, when an outer magnet 1223 (i.e., the outer wall 12214 includes the outer magnet 1223) is provided on the outer wall 12214 of the magnetic shield 1221, and the magnetization directions of the inner magnet 1222 and the outer magnet 1223 are opposite (for example, the N pole of the inner magnet 1222 can be located at the upper end, and the N pole of the outer magnet 1223 can be located at the lower end), the inner wall 12212 of the magnetic shield 1221 exhibits a magnetic field zero pole, and the inner wall 12212 is not responsible for magnetic conduction. At this time, the inner wall 12212 of the magnetic shield 1221 mainly serves as a connection and support. In order to reduce the mass and size of the speaker 120, the thickness of the inner wall 12212 of the magnetic shield 1221 can be designed to be thinner (for example, less than or equal to 0.4 mm). In some embodiments, as shown in FIG61G, in order to further reduce the mass and size of the speaker 120, the thickness of the inner sidewall 12212 of the magnetic shield 1221 can also be designed to be 0, that is, the inner sidewall 12212 structure is eliminated.

[0353] In some embodiments, in order to reduce the mass and size of the speaker 120, the inner sidewall 12212 may be perforated.

[0354] Since the outer magnet 1223 and the inner magnet 1222 need to be connected, the annular sidewall of the magnetic shield 1221 needs to retain at least a portion of the inner sidewall 12212 to connect the outer sidewall 12214 to the bottom wall 12211 of the magnetic shield 1221. For example, the outer sidewall 12214 of the long side of the magnetic shield 1221 can be connected to the bottom wall 12211 of the magnetic shield 1221 via the inner sidewall 12212, and the short side of the magnetic shield 1221 may not have an inner sidewall 12212.

[0355] To improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, thereby enhancing the output performance of the speaker 120 and improving the active noise cancellation effect of the headphones in open-back design, the driving forces of the first voice coil 123-1 and the second voice coil 123-2 can be close or the same. In some embodiments, the dimensions of the inner magnet 1222 and the outer magnet 1223 can be designed to make the magnetic field strength near the first voice coil 123-1 and the second voice coil 123-2 similar, thereby improving the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2 and enhancing the active noise cancellation effect of the headphones.

[0356] Figure 62 is a schematic diagram of the frequency response curves of a loudspeaker corresponding to different sizes of inner and outer magnets according to some embodiments of this specification, and Figure 63 is another structural schematic diagram of a loudspeaker according to some embodiments of this specification.

[0357] In some embodiments, the data in FIG62 are measured under the conditions that the width of the magnetic gap is 1.1 mm and the thickness of the inner sidewall 12212 of the magnetic shield 1221 is 0.7 mm.

[0358] Referring to Figure 63, the ratio of the size Wim of the inner magnet 1222 to the size Wom of the outer magnet 1223 is defined as Wim / Wom. In Figure 62, L701 represents the BL value of the speaker 120 when Wim / Wom is 0.32, L702 represents the BL value of the speaker 120 when Wim / Wom is 0.56, L703 represents the BL value of the speaker 120 when Wim / Wom is 0.85, L704 represents the BL value of the speaker 120 when Wim / Wom is 1.22, L705 represents the BL value of the speaker 120 when Wim / Wom is 1.70, and L706 represents the BL value of the speaker 120 when Wim / Wom is 1.70. L707 represents the BL value of speaker 120 when Wim / Wom is 2.35, L708 represents the BL value of speaker 120 when Wim / Wom is 3.28, L708 represents the BL value of speaker 120 when Wim / Wom is 4.70, L709 represents the BL value of speaker 120 when Wim / Wom is 7.19, L710 represents the BL value of speaker 120 when Wim / Wom is 15.59, and L711 represents the BL value of speaker 120 when Wim / Wom is 33.43.

[0359] Please refer to Figure 63. The dimensions mentioned refer to the dimensional parameters of the relevant components in the direction perpendicular to the vibration direction. For example, the thickness of the outer magnet 1223 refers to the distance between the outer surface and the inner surface of the outer magnet 1223, and the dimensions of the inner magnet 1222 refer to the dimensions of the cross-section of the inner magnet 1222.

[0360] As shown in Figure 62, the BL value of the speaker 120 is optimal when the ratio of the size of the inner magnet 1222 to the thickness of the outer magnet 1223 is 7.19. Further increasing the ratio of the size of the inner magnet 1222 to the thickness of the outer magnet 1223 will reduce the BL value of the speaker 120.

[0361] Therefore, by designing the size ratio of the outer magnet 1223 and the inner magnet 1222, the electromagnetic conversion efficiency of the speaker 120 can be guaranteed, the driving force of the voice coil assembly 123 can be improved, the output of the speaker 120 can be improved, and the active noise cancellation effect of the headphones on large ambient noise can be improved.

[0362] For example, the size of the loudspeaker 120 in the long axis direction is larger than its size in the short axis direction; in this case, the ratio of the size of the inner magnet 1222 in the long axis direction to the thickness of the outer magnet 1223 in the long axis direction can be between 1.7 and 33; the ratio of the size of the inner magnet 1222 in the short axis direction to the thickness of the outer magnet 1223 in the short axis direction is between 1.7 and 33.

[0363] Furthermore, in some embodiments, the ratio of the dimension of the inner magnet 1222 in the long axis direction to the thickness of the outer magnet 1223 in the long axis direction may not exceed 6.7, and the ratio of the dimension of the inner magnet 1222 in the short axis direction to the thickness of the outer magnet 1223 in the short axis direction may not exceed 2.7. Through the above-described design, the BL value of the speaker 120 can be significantly improved, thereby enhancing the sound output performance of the speaker 120 and improving the active noise cancellation effect of the headphones against significant ambient noise.

[0364] For example, the speaker 120 has a circular outline, and the ratio of the size of the inner magnet 1222 in the radial direction (i.e., the direction corresponding to the major axis or the minor axis) to the thickness of the outer magnet 1223 in the radial direction is between 1.7 and 33.

[0365] It should be noted that the thickness of the outer magnet 1223 refers to the distance between the outer surface and the inner surface of the outer magnet 1223.

[0366] When the volume of the outer magnet 1223 is too small relative to the volume of the inner magnet 1222, the driving force of the second voice coil 123-2, which is closer to the outer magnet 1223 and farther from the inner magnet 1222, is smaller, while the driving force of the first voice coil 123-1, which is farther from the outer magnet 1223 and closer to the inner magnet 1222, is larger. This results in a large difference in driving force between the first voice coil 123-1 and the second voice coil 123-2. Similarly, when the volume of the outer magnet 1223 is too large relative to the volume of the inner magnet 1222, the driving force of the second voice coil 123-2, which is closer to the outer magnet 1223 and farther from the inner magnet 1222, is larger, while the driving force of the first voice coil 123-1, which is farther from the outer magnet 1223 and closer to the inner magnet 1222, is smaller. This also results in a large difference in driving force between the first voice coil 123-1 and the second voice coil 123-2. That is, when the volume difference between the outer magnet 1223 and the inner magnet 1222 is too large, it will result in a significant difference in driving force between the first voice coil 123-1 and the second voice coil 123-2, affecting the active noise cancellation effect of the headphones. In some embodiments, in order to improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2 and improve the active noise cancellation effect of the headphones, the volume ratio of the outer magnet 1223 to the inner magnet 1222 can be 0.3-3. In some embodiments, in order to further improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2 and improve the active noise cancellation effect of the headphones, the volume ratio of the outer magnet 1223 to the inner magnet 1222 can be 0.5-1.5.

[0367] Figures 64A and 64B are schematic diagrams of the frequency response curves of loudspeakers corresponding to magnets of different sizes and magnetic shields in Figure 63.

[0368] In some embodiments, FIG64A shows the trend of electromagnetic conversion efficiency of loudspeaker 120 when the size of magnet (e.g., inner magnet 1222) is constant (e.g., 2 mm) and the thickness of magnetic shield 1221 (e.g., bottom wall 12211) or first magnetic plate 1224 is changed; FIG64B shows the trend of electromagnetic conversion efficiency of loudspeaker 120 when the thickness of magnetic shield 1221 (e.g., bottom wall 12211) or first magnetic plate 1224 is constant (e.g., 0.7 mm) and the size of magnet (e.g., inner magnet 1222) is changed.

[0369] As shown in Figure 64A, as the thickness of the magnetic shield 1221 or the first magnetic plate 1224 increases (i.e., the ratio of the magnet size to the thickness of the magnetic shield 1221, h_magnet / h_lead, decreases), the BL value of the speaker 120 tends to increase. However, when the thickness of the magnetic shield 1221 or the first magnetic plate 1224 increases to a certain value, the BL value will reach its maximum value. Excessively increasing the thickness of the magnetic shield 1221 or the first magnetic plate 1224 will cause the magnetic field lines to disperse and not be effectively concentrated near the voice coil assembly 123, thus reducing the magnetic field near the voice coil assembly 123. The BL value decreases when the thickness of the magnetic shield 1221 or the first magnetic plate 1224 decreases (i.e., the ratio of the magnet's size to the thickness of the magnetic shield 1221 increases). This reduces the magnetic saturation of the magnetic shield 1221 or the first magnetic plate 1224, thereby reducing the magnetic permeability and consequently reducing the magnetic field strength passing through the voice coil assembly 123. The BL value reaches its maximum when the ratio of the magnet's size to the thickness of the magnetic shield 1221 or the first magnetic plate 1224 is 1.4. However, when the ratio of the magnet's size to the thickness of the magnetic shield 1221 or the first magnetic plate 1224 is between 1 and 4, the BL value is relatively large.

[0370] As shown in Figure 64B, as the size of the magnet increases (i.e., the ratio h_magnet / h_lead of the magnet size to the thickness of the magnetic shield 1221 or the first magnetic plate 1224 decreases), the BL value of the speaker 120 shows an increasing trend. However, the rate of increase of the BL value decreases. This may be because as the size of the magnet increases, the magnetic shield 1221 or the first magnetic plate 1224 becomes magnetically saturated. Continuing to increase the size of the magnet does not significantly increase the amount of magnetic field that can be gathered through the magnetic shield 1221 or the first magnetic plate 1224 and pass through the voice coil assembly 123. Specifically, when the ratio of the magnet size to the thickness of the magnetic shield 1221 or the first magnetic plate 1224 is between 1 and 4, the rate of increase of the BL value is large. When the ratio of the magnet size to the thickness of the magnetic shield 1221 or the first magnetic plate 1224 is greater than 4, the rate of increase slows down significantly, and the magnetic shield 1221 or the first magnetic plate 1224 begins to become magnetically saturated, reducing the overall electromagnetic conversion efficiency of the speaker 120.

[0371] Therefore, in order to improve the electromagnetic conversion efficiency of the loudspeaker 120, in some embodiments, the ratio of the size of the inner magnet 1222 to the thickness of the magnetic shield 1221 (e.g., bottom wall 12211) or the first magnetic plate 1224 can be between 1 and 4, and the ratio of the thickness of the outer magnet 1223 to the thickness of the magnetic shield 1221 (e.g., side wall 12212) can be between 1 and 4.

[0372] In some embodiments, the structure of the magnetic circuit assembly 122 can be designed to enhance the driving force of the speaker 120. In some embodiments, referring to FIG51, when the long side portion and the short side portion of the outer magnet 1223 are separate structures, in order to fix the outer magnet 1223 and prevent the outer magnet 1223 from falling off, the magnetic circuit assembly 122 may include a frame 125. The frame 125 is disposed around the outer magnet 1223, and the frame 125 cooperates with the magnetic guide cover 1221 to fix the outer magnet 1223.

[0373] Figure 65 is another cross-sectional structural schematic diagram of a sound-generating component according to some embodiments of this specification, and Figure 66 is an exploded structural schematic diagram of a loudspeaker according to some embodiments of this specification.

[0374] In some embodiments, referring to Figures 24, 65, and 66, a second magnetic guide plate 1225 may be provided at one end of the outer magnet 1223 away from the extension 12213. The magnetic circuit assembly 122 also includes a support assembly, which may include a first support 122-4 and a second support 122-5; wherein, the first support 122-4 is connected around the outer periphery of the second magnetic guide plate 1225, and the second support 122-5 is connected around the outer periphery of the extension 12213; the first support 122-4 and the second magnetic guide plate 1225, as well as the second support 122-5 and the extension 12213, may be connected by injection molding, adhesive, bolts, snaps, etc.; the outer periphery of the first diaphragm 121-1 is fixed to the first support 122-4 (e.g., adhesive), and the outer periphery of the second diaphragm 121-2 is fixed to the second support 122-5 (e.g., adhesive).

[0375] On the one hand, by combining the first bracket 122-4, the second bracket 122-5, and the second magnetic plate 1225, the basket or the aforementioned frame 125 in some existing loudspeakers can be replaced, which allows the external magnet 1223 to have a larger volume size, enhances the magnetic flux, and thus enhances the driving force of the voice coil assembly 123; at the same time, it can also make the structure of the loudspeaker 120 more compact, reduce the assembly difficulty, and improve the assembly effect.

[0376] On the other hand, by means of the cooperation of the first bracket 122-4 and the second bracket 122-5, as well as the magnetic cover 1221 and the diaphragm, the internal space of the speaker 120 can be enclosed to form a relatively closed cavity (i.e., the common cavity 111-3). The first bracket 122-4 and the second bracket 122-5 can serve as structural connection carriers between the speaker 120 and the first housing 110 or between the speaker 120 and the limiting component 130, so as to securely confine the speaker 120 inside the first housing 110 and form a first acoustic cavity 111-1 and a second acoustic cavity 111-2 that are relatively independent of the common cavity 111-3.

[0377] In some embodiments, referring to FIG66, the first bracket 122-4 has a first receiving groove surrounding the second magnetic plate 1225, and the second bracket 122-5 has a second receiving groove surrounding the extension 12213; wherein, the outer periphery of the second magnetic plate 1225 is inserted into the first receiving groove, and the outer periphery of the extension 12213 is inserted into the second receiving groove; exemplaryly, the first bracket 122-4 can be integrally formed on the second magnetic plate 1225 by injection molding, die-cutting or other methods, and the first bracket 122-4 covers the outer periphery of the second magnetic plate 1225, at which time the first receiving groove is equivalent to being naturally formed in the first bracket 122-4.

[0378] Based on the set receiving groove, the structural connection area between the bracket and the corresponding magnetic plate is effectively increased, so that the bracket and the corresponding magnetic plate can be stably combined into one piece (for example, the bracket and the corresponding magnetic plate are integrally injection molded), which helps to reduce the number of parts of the speaker 120 and reduce the assembly difficulty of the speaker 120.

[0379] In some embodiments, referring to Figures 65 and 66, the first support 122-4, the second magnetic plate 1225, and the first diaphragm 121-1 together form a first chamber 120a inside the speaker 120, and the second support 122-5, the extension 12213, and the second diaphragm 121-2 together form a second chamber 120b inside the speaker 120; it can be understood that the first chamber 120a and the second chamber 120b are equivalent to a part of the common cavity 111-3, and the two are located on both sides of the magnetic circuit assembly in the vibration direction.

[0380] At this point, please refer to Figure 66. The first bracket 122-4 and the second bracket 122-5 are each provided with a positioning structure 120c and a through-hole structure 120d. For ease of distinction and description, the positioning structure 120c and the through-hole structure 120d provided on the first bracket 122-4 are respectively defined as the first positioning structure and the first through-hole structure, and the positioning structure 120c and the through-hole structure 120d provided on the second bracket 122-5 are respectively defined as the second positioning structure and the second through-hole structure.

[0381] The first positioning structure is located within the first chamber 120a and is primarily used to position and restrict the wire of the first voice coil 123-1 onto the first bracket 122-4 within the first chamber 120a. The first through-hole structure penetrates the side wall of the first bracket 122-4 (e.g., the side wall in the short axis direction) so that the wire of the first voice coil 123-1 can be led out from the inside of the speaker 120 and connected to the circuit board 150 located around the speaker 120 (this circuit board 150 enables electrical connection between the speaker 120 and the microphone assembly and the headphone circuit board assembly). Similarly, the second positioning structure is located within the second chamber 120b and is primarily used to position and restrict the wire of the second voice coil 123-2 onto the second bracket 122-5 within the second chamber 120b. The second through-hole structure penetrates the side wall of the second bracket 122-5 so that the wire of the second voice coil 123-2 can be led out from the inside of the speaker 120 and connected to the circuit board 150.

[0382] Therefore, through the cooperation between the corresponding chamber, support, positioning structure 120c, and through-hole structure 120d, the overall compactness of the loudspeaker 120 can be effectively enhanced, and the voice coil wire can be restricted to avoid interference with the diaphragm vibration. In specific implementation, the positioning structure 120c can be a mechanical structure such as a clip set on the corresponding support, or it can be a structure formed by fixing the voice coil wire with adhesive.

[0383] In some embodiments, referring to Figure 66, the first support 122-4 and the second support 122-5 are separately arranged in the vibration direction, thus forming a receiving gap between them that surrounds the outer magnet 1223; the circuit board 150 can be housed and fixed within this receiving gap, for example, by attaching it to the outer peripheral surface of the first outer magnet 1223-1. This effectively reduces the overall size of the speaker 120, further enhancing the structural compactness of the speaker 120.

[0384] As described in some of the embodiments above, a limiting component 130 is provided between the first housing 110 and the speaker 120. Referring to FIG. 66, a space for accommodating sealant can be formed at the junction of the limiting component 130 and the speaker 120. For example, the peripheral sidewall of the first cover 133 surrounds the outer periphery of the first support 122-4 to form a space for accommodating sealant between them, and the peripheral sidewall of the second cover 134 surrounds the outer periphery of the second support 122-5 to form a space for accommodating sealant between them. By filling the space for accommodating sealant, a sealed and fixed connection between the limiting component 130 and the speaker 120 is achieved.

[0385] In this way, the sealant in the space can be used to enhance the stability and sealing of the connection between the limiting component 130 and the speaker 120, and the structural gap between the limiting component 130 and the speaker 120 can be eliminated, thereby enhancing the sealing of the first acoustic cavity 111-1 and the second acoustic cavity 111-2, and preventing sound leakage from the joint between the limiting component 130 and the speaker 120 from affecting the sound output of the headphones.

[0386] In some embodiments, referring to FIG66, one or both of the first bracket 122-4 and the second bracket 122-5 are provided with an air pressure balancing channel 120e. The air pressure balancing channel 120e can be arranged to pass through the corresponding bracket in a direction perpendicular to the vibration direction (e.g., the major axis direction, the minor axis direction, etc.), so that the air pressure balancing channel 120e connects the external space of the speaker 120 with the common cavity 111-3 formed between the first bracket 122-4, the second bracket 122-5, the first diaphragm 121-1, the second diaphragm 121-2 and the external magnetic circuit member 122-1.

[0387] When the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously in the same direction, the air pressure balance channel 120e can ensure that the gas in the common cavity 111-3 moves back and forth with the vibration of the two diaphragms. This avoids the first diaphragm 121-1 and the second diaphragm 121-2 from affecting the peaks and valleys of the frequency response curve due to the compression of the gas in the common cavity 111-3, thereby improving the sound output quality of the headphones and thus improving the active noise cancellation effect of the headphones.

[0388] Meanwhile, when the first diaphragm 121-1 and the second diaphragm 121-2 vibrate inconsistently (e.g., vibrating in opposite directions, or vibrating with different amplitudes), the air pressure balance channel 120e can be used to balance the internal and external air pressure of the common cavity 111-3, thereby preventing the gas in the common cavity 111-3 from interfering with the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, and ensuring sound output.

[0389] In some embodiments, the air pressure balance channel 120e can be covered with a mesh, a waterproof and breathable membrane, etc., to improve the waterproof performance of the speaker 120.

[0390] As in some of the aforementioned embodiments, the magnetic circuit assembly may include a magnetic shield 1221, an inner magnet 1222, an outer magnet 1223, etc. By improving the design of the magnetic circuit structure, it is helpful to further enhance the driving force of the speaker 120.

[0391] Figure 67A is another exploded view of a loudspeaker according to some embodiments of this specification, Figure 67B is a cross-sectional view of the loudspeaker shown in Figure 67A in the width direction, and Figure 67C is a cross-sectional view of the loudspeaker shown in Figure 67A in the length direction. As shown in Figures 67A-67C, in some embodiments, the outer magnet 1223 can be a ring structure, and the outer magnet 1223 is arranged around the magnetic guide cover 1221. The ring structure of the outer magnet 1223 allows the outer magnet 1223 to have a larger volume, thereby increasing the magnetic flux and thus increasing the driving force of the loudspeaker 120. Moreover, the ring structure of the outer magnet 1223 can also reduce the assembly difficulty and improve the assembly efficiency.

[0392] In some embodiments, when the outer magnet 1223 can be a ring structure, the magnetic circuit assembly 122 may not have a frame 125, but instead uses an upper fixing frame 128-1 and a lower fixing frame 128-2 to mount and fix the outer magnet 1223. Specifically, the first diaphragm 121-1 can be fixed to the upper fixing frame 128-1, and the upper side of the outer magnet 1223 is connected to the upper fixing frame 128-1 through a third magnetic guide plate 1226; the second diaphragm 121-2 can be fixed to the lower fixing frame 128-2, and the lower side of the outer magnet 1223 is connected to the lower fixing frame 128-2 through a second magnetic guide plate 1225. In this case, the lower side of the inner magnet 1222 is connected to the bottom of the magnetic guide cover 1221, and the upper side of the inner magnet 1222 is connected to the first magnetic guide plate 1224. By designing the upper fixing bracket 128-1 and the lower fixing bracket 128-2, the frame 125 can be eliminated, thereby allowing the magnetic circuit assembly 122 to have a larger design size, which will further increase the volume of the magnets (e.g., inner magnet 1222, outer magnet 1223, etc.) to further increase the driving force of the speaker 120.

[0393] In some embodiments, the upper fixing frame 128-1 and the lower fixing frame 128-2 may be made of plastic; correspondingly, the fixing frames may be connected to the corresponding magnetic plates by means of injection molding, adhesive, bolts, clips, etc. In some embodiments, the upper fixing frame 128-1 and the lower fixing frame 128-2 may also be made of metal; correspondingly, the fixing frames may be connected to the corresponding magnetic plates by means of adhesive, welding, bolts, clips, etc.

[0394] In some embodiments, the outer magnetic plate corresponding to the outer magnet 1223 (e.g., the second magnetic plate 1225, the third magnetic plate 1226, the extension 12213, etc.) may include two interconnected components, one of which is used to connect to the corresponding fixing frame, and the other is used to connect to the outer magnet 1223. In some embodiments, the two components may be separately connected or integrally formed.

[0395] Figure 68A is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification. Referring to Figure 68A, in some embodiments, the magnetic circuit assembly 122 may further include a magnetic circuit fixing ring 129, which is sleeved on the outside of the upper fixing frame 128-1 and the lower fixing frame 128-2, as shown in Figure 68A. The magnetic circuit fixing ring 129 connects the fixing frame, the corresponding outer magnetic guiding plate (e.g., the second magnetic guiding plate 1225, the third magnetic guiding plate 1226, the extension 12213, etc.), and the outer magnet 1223 into a whole, further improving the installation stability of the magnetic circuit assembly 122, thereby improving the vibration stability of the loudspeaker 120. In some embodiments, the magnetic circuit fixing ring 129 and the corresponding fixing frame may be separately connected or integrally formed.

[0396] Figure 68B is a schematic diagram of another internal structure of a loudspeaker according to some embodiments of this specification. Referring to Figure 68B, in some embodiments, the magnetic circuit assembly 122 may not have an upper fixing frame 128-1 and a lower fixing frame 128-2. Instead, a magnetic circuit fixing ring 129 can replace the upper fixing frame 128-1 and the lower fixing frame 128-2, and the magnetic circuit assembly 122 can be directly assembled and fixed by the magnetic circuit fixing ring 129, thereby reducing the assembly difficulty.

[0397] In some embodiments, the material of the magnetic circuit fixing ring 129 can be the same as that of the upper fixing frame 128-1 and the lower fixing frame 128-2, and the connection method between the magnetic circuit fixing ring and the corresponding fixing frame or the corresponding outer magnetic plate can be the same as the connection method between the corresponding fixing frame and the corresponding outer magnetic plate.

[0398] Figure 69A is a structural schematic diagram of a loudspeaker including a magnetic circuit fixing ring according to some embodiments of this specification. Figure 69B is a structural schematic diagram of the loudspeaker shown in Figure 69A from another perspective. Figure 70A is another structural schematic diagram of a loudspeaker including a magnetic circuit fixing ring according to some embodiments of this specification. Figure 70B is a structural schematic diagram of the loudspeaker shown in Figure 70A from another perspective.

[0399] Referring to Figures 69A and 69B, in some embodiments, the magnetic circuit fixing ring 129 may include two annular sub-rings, which are respectively disposed on the upper and lower sides of the outer magnet 1223 to install and fix the upper and lower sides of the outer magnet 1223 and the corresponding outer magnetic plate, fixing frame, etc.

[0400] Referring to Figures 70A and 70B, in some embodiments, the magnetic circuit fixing ring 129 may include two semi-annular sub-rings. The interval between the two sub-rings may be set along the short side of the speaker 120. In this case, the sub-rings can be installed and fixed to the long side of the outer magnetic plate, the corresponding long side of the outer magnet 1223, and the corresponding long side of the mounting bracket. In other embodiments, the interval between the two sub-rings may also be set along the long side of the speaker 120. In this case, the sub-rings can be installed and fixed to the short side and part of the long side of the outer magnetic plate, the corresponding short side and part of the corresponding long side of the outer magnet 1223, and the corresponding short side and part of the corresponding long side of the mounting bracket.

[0401] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0402] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0403] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0404] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are sometimes modified with the modifier "approximate." Unless otherwise stated, "approximate" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0405] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A loudspeaker, comprising: a magnetic circuit assembly; a voice coil assembly, at least a portion of the voice coil being located in a magnetic gap of the magnetic circuit assembly; a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm being spaced apart in a vibration direction; at least one of the first diaphragm and the second diaphragm being connected with the voice coil assembly, the voice coil assembly being configured to drive the first diaphragm and the second diaphragm to vibrate synchronously and in the same direction; wherein the voice coil assembly comprises a first voice coil and a second voice coil arranged along the vibration direction, the first diaphragm being connected with the first voice coil, the second diaphragm being connected with the second voice coil, the first voice coil and the second voice coil being connected through a third connecting member, the first voice coil and the second voice coil respectively driving the first diaphragm and the second diaphragm to vibrate synchronously and in the same direction.

2. The loudspeaker of claim 1, wherein, The third connecting member comprises a skeleton, the skeleton comprising a first portion and a second portion formed integrally, the first voice coil being arranged on an outer circumferential side or an inner circumferential side of the first portion, the second voice coil being arranged on an outer circumferential side or an inner circumferential side of the second portion.

3. The loudspeaker of claim 1, wherein, The third connecting member comprises two skeletons connected with each other, the first voice coil being arranged on an outer circumferential side or an inner circumferential side of one of the skeletons, the second voice coil being arranged on an outer circumferential side or an inner circumferential side of the other skeleton.

4. The loudspeaker of claim 3, wherein, The two skeletons are directly connected.

5. The loudspeaker of claim 3, wherein, The third connecting member further comprises a sub connecting portion, the two skeletons being connected through the sub connecting portion.

6. The loudspeaker of claim 1, wherein, In a reference plane perpendicular to the vibration direction, there is a gap between a projection of the first voice coil and a projection of the second voice coil to form an avoiding passage allowing the magnetic circuit assembly to pass through the voice coil assembly; or, in another reference plane parallel to the vibration direction, there is a gap between a projection of the first voice coil and a projection of the second voice coil to form the avoiding passage.

7. The loudspeaker of claim 6, wherein, The loudspeaker comprises a long axis direction and a short axis direction, the first voice coil and the second voice coil each comprising a long side wall parallel to the long axis direction and a short side wall parallel to the short axis direction; wherein, a size of the short side wall of the first voice coil is the same as a size of the short side wall of the second voice coil, and a size of the long side wall of the first voice coil is different from a size of the long side wall of the second voice coil; or, a size of the short side wall of the first voice coil is different from a size of the short side wall of the second voice coil, and a size of the long side wall of the first voice coil is the same as a size of the long side wall of the second voice coil; or, a size of the short side wall of the first voice coil is different from a size of the short side wall of the second voice coil, and a size of the long side wall of the first voice coil is different from a size of the long side wall of the second voice coil.

8. The loudspeaker of claim 6, wherein, The magnetic circuit assembly comprises an inner magnet and a magnetic shield, the magnetic shield comprising a bottom wall and side walls located at two ends of the bottom wall, top ends of the side walls being provided with extension portions, the inner magnet being arranged on the bottom wall, the side walls passing through the avoiding passage so that the extension portions extend out of the voice coil assembly.

9. The loudspeaker of claim 8, wherein, The side walls are hollow; or a material of the side walls comprises a non-magnetic material.

10. The loudspeaker of claim 8, wherein, Four corner angles of the bottom wall are respectively provided with step structures.

11. The loudspeaker of claim 8, wherein, The connecting position of the side wall and the bottom wall and the connecting position of the side wall and the extension are provided with a rounded corner transition.

12. The loudspeaker of claim 8, wherein, The bottom wall is provided with a reinforcing member.

13. The loudspeaker of claim 1, wherein, The magnetic circuit assembly comprises a magnetic conductive cover and an inner magnet, the magnetic conductive cover comprises a side wall and a bottom wall, the side wall comprises a folded structure, the folded structure comprises an inner side wall and an outer side wall, the bottom wall is connected with the inner side wall, a first magnetic gap is formed between the inner side wall and the inner magnet, a second magnetic gap is formed between the inner side wall and the outer side wall, the first voice coil is at least partially located in the first magnetic gap, and the second voice coil is at least partially located in the second magnetic gap.

14. The loudspeaker of claim 13, wherein, The outer side wall comprises an outer magnet, the first magnetic gap is formed between the inner magnet and the inner side wall, and the second magnetic gap is formed between the outer magnet and the inner side wall.

15. The loudspeaker of claim 14, wherein, The polarization direction of the inner magnet is the same as the magnetization direction of the outer magnet, the loudspeaker comprises a long axis direction and a short axis direction, and in the short axis direction or the long axis direction, the ratio of the thickness of the inner side wall to the size of the magnetic conductive cover is 0.05-0.

16.

16. The loudspeaker of claim 14, wherein, The polarization direction of the inner magnet is opposite to the magnetization direction of the outer magnet, and the thickness of the inner side wall is less than or equal to 0.4 mm.

17. The loudspeaker of claim 16, wherein, The inner side wall is hollow.

18. The loudspeaker of claim 13, wherein, The inner side wall comprises a first outer magnet, the outer side wall comprises a second outer magnet, the first magnetic gap is formed between the inner magnet and the first outer magnet, and the second magnetic gap is formed between the first outer magnet and the second outer magnet.

19. A loudspeaker as claimed in any of claims 14 to 18 wherein, In the short axis direction or the long axis direction, the ratio of the size of the inner magnet to the thickness of the outer magnet is between 1.7 and 33.

20. The loudspeaker of claim 19, wherein, In the long axis direction, the ratio of the size of the inner magnet to the thickness of the outer magnet is less than or equal to 6.7; in the short axis direction, the ratio of the size of the inner magnet to the thickness of the outer magnet is less than or equal to 2.

7.

21. The loudspeaker of claim 1, wherein, The loudspeaker further comprises a support assembly, the support assembly surrounds the periphery of the voice coil assembly, and the support assembly and the voice coil assembly are spaced apart in a radial direction perpendicular to the vibration direction. The first diaphragm and the second diaphragm each comprise a folded ring, a middle piece and a fixing ring, the folded ring surrounds and is connected to the outer periphery of the middle piece, and the middle piece is connected to the voice coil assembly; the part of the folded ring away from the middle piece in the radial direction is connected to the fixing ring, and the fixing ring is connected to the support assembly; wherein the folded ring comprises a first connecting portion, a folded ring portion surrounding and connected to the outer periphery of the first connecting portion, and a second connecting portion surrounding and connected to the outer periphery of the folded ring portion; wherein in the vibration direction, the first connecting portion is connected to the inner surface of the voice coil assembly and the outer surface of the middle piece away from the voice coil assembly, and the second connecting portion is connected to the inner surface of the voice coil assembly and the support assembly.

22. The loudspeaker of claim 21, wherein, The diaphragm further comprises a third connecting portion and a fourth connecting portion, one end of the third connecting portion in the vibration direction is connected to the connection between the folded ring portion and the first connecting portion, and one end of the fourth connecting portion in the vibration direction is connected to the connection between the folded ring portion and the second connecting portion. In the radial direction, the inner peripheral surface of the third connecting portion on the side facing the voice coil assembly is connected to the peripheral surface of the middle gasket, and the outer peripheral surface of the fourth connecting portion on the side away from the voice coil assembly is connected to the inner peripheral surface of the fixing ring on the side facing the voice coil assembly.

23. The loudspeaker of claim 22, wherein, In the radial direction, the distance between the outer peripheral surface of the third connecting portion on the side away from the voice coil assembly and the inner peripheral surface of the third connecting portion on the side facing the voice coil assembly is a first width, and the distance between the outer peripheral surface of the third connecting portion and the outer peripheral surface of the fourth connecting portion is a second width, and the ratio of the first width to the second width is between 0.04 and 0.

32.

24. The loudspeaker of claim 22, wherein, In the radial direction, the distance between the inner peripheral surface of the third connecting portion and the outer peripheral surface of the fourth connecting portion is a third width, and the ratio of the average wall thickness of the folded ring portion to the third width is not greater than 0.

12.

25. The loudspeaker of claim 22, wherein, In the vibration direction, the distance from the inner surface of the first connecting portion to the plane on which the inner surface of the second connecting portion lies is a first height, and in the radial direction, the distance between the inner peripheral surface of the third connecting portion and the outer peripheral surface of the fourth connecting portion is a third width, and the ratio of the first height to the third width is not greater than 0.

232.

26. The loudspeaker of claim 22, wherein, The folded ring further comprises a fifth connecting portion spaced apart from the first connecting portion in the vibration direction, and the third connecting portion is connected between the fifth connecting portion and the folded ring portion in the vibration direction. In the vibration direction, the outer surface of the fifth connecting portion is connected to the inner surface of the middle gasket, the part of the inner surface of the middle gasket not connected to the fifth connecting portion is connected to the voice coil assembly, and the minimum distance between the fifth connecting portion and the voice coil assembly in the radial direction is not less than 0.5 mm.

27. The loudspeaker of claim 21, wherein, The folded ring portion is sequentially divided into a first arc-shaped area, a second arc-shaped area and a third arc-shaped area along the radial direction according to arc length, the ratio of the average wall thickness of the first arc-shaped area to the average wall thickness of the second arc-shaped area is not greater than 1.2, and the ratio of the average wall thickness of the third arc-shaped area to the average wall thickness of the second arc-shaped area is not greater than 1.

2.

28. The loudspeaker of claim 21, wherein, The folded ring portion is curved and arched away from the side of the voice coil assembly relative to the first connecting portion in the vibration direction. In the vibration direction, the distance from the inner surface of the first connecting portion to the plane on which the inner surface of the second connecting portion lies is a first height, and the distance from the vertex of the folded ring portion to the plane on which the inner surface of the second connecting portion lies is a second height, and the ratio of the first height to the second height is not greater than 0.

36.

29. The loudspeaker of claim 21, wherein, The material of the folded ring comprises a silica gel material, and the material of the middle gasket comprises one or more of magnesium-aluminum alloy, carbon fiber, surface-coated aluminum polymethyl methacrylimide and surface-coated aluminum polyethylene naphthalate.

30. The loudspeaker of claim 29, wherein, The middle gasket has a central area and an edge area connected around the outer periphery of the central area; in the vibration direction, the geometric center of the central area and the plane on which the edge area lies have a height difference; wherein the folded ring and the voice coil assembly are connected to the edge area. In the radial direction, the inner peripheral surface of the third connecting portion on the side facing the voice coil assembly is connected to the peripheral surface of the middle gasket, and the outer peripheral surface of the fourth connecting portion on the side away from the voice coil assembly is connected to the inner peripheral surface of the fixing ring on the side facing the voice coil assembly.

31. The loudspeaker of claim 30, wherein, The middle earpiece further has a connecting region, which is connected between the central region and the edge region and is obliquely arranged in the vibration direction.

32. An earphone comprising the loudspeaker of any one of claims 1-31, the earphone further comprising: a first housing, the loudspeaker being arranged in the first housing; in a wearing state, the first housing comprises an inner side wall facing a side of the outer ear canal, and an outer side wall opposite to the inner side wall and away from a side of the outer ear canal, the inner side wall being provided with a first sound outlet, and the outer side wall being provided with a second sound outlet; the first diaphragm of the loudspeaker and the inner side wall form a first acoustic cavity communicating with the first sound outlet, and the second diaphragm of the loudspeaker and the outer side wall form a second acoustic cavity communicating with the second sound outlet.

33. The earphone of claim 32, wherein, The earphone further comprises a limiting component, which is arranged between the loudspeaker and the first housing; the limiting component is provided with a sound guide hole, and in a reference plane perpendicular to the vibration direction, a projection of the sound guide hole, a projection of the first sound outlet, a projection of the second sound outlet, a projection of the first diaphragm and a projection of the second diaphragm at least partially overlap.

34. The earphone of claim 33, wherein, In the reference plane, the projection of the first sound outlet falls within the projection of the sound guide hole; or, in the reference plane, a projection area of an overlapping region of the projection of the first sound outlet and the projection of the sound guide hole is not less than 80% of a projection area of the projection of the sound guide hole.

35. The earphone of claim 32, wherein, The limiting component elastically abuts against the first housing.

36. The earphone of claim 32, wherein, The limiting component comprises a second housing and a sealing ring, the second housing is arranged inside the first housing; the loudspeaker is arranged inside the second housing and fixedly connected with the second housing; the sealing ring is connected between the second housing and the first housing; wherein the sound guide hole is arranged in the second housing.

37. The earphone of claim 36, wherein, The second housing comprises a first cover and a second cover, one end of the loudspeaker in the vibration direction extends into the first cover, and the other end of the loudspeaker in the vibration direction extends into the second cover; wherein: the first cover and the second cover each have a transverse side wall and a longitudinal side wall, the transverse side wall is spaced apart from and opposite to the first diaphragm or the second diaphragm in the vibration direction, and the longitudinal side wall is closed around the vibration direction and fixedly connected with the loudspeaker; the transverse side wall comprises a central portion and an arcuate portion surrounding the central portion, at least part of the sound guide hole is arranged through the central portion, and one end of the arcuate portion away from the central portion is connected with the longitudinal side wall.

38. The earphone of claim 32, wherein, The first sound outlet and the second sound outlet are each provided with an acoustic resistance net; a ratio of an acoustic impedance rate of the acoustic resistance net of the second sound outlet to an acoustic impedance rate of the acoustic resistance net of the first sound outlet is not less than 10.

39. The earphone of claim 32, wherein, In a reference plane perpendicular to the vibration direction, an area proportion of the projection of the second sound outlet and / or the projection of the first sound outlet in the projection of the corresponding side wall of the first housing is not less than 10%.

40. The earphone of claim 32, wherein, The loudspeaker comprises a long axis direction, in which the size ratio of the second sound hole and / or the first sound hole to the size of the first shell is not less than 0.

3.

41. The earphone of claim 32, wherein, In a reference plane perpendicular to the vibration direction, the distance between the centroid of the projection of the second sound hole and the centroid of the projection of the corresponding side wall of the first shell is not greater than 5mm; and / or, the distance between the centroid of the projection of the first sound hole and the centroid of the projection of the corresponding side wall of the first shell is not greater than 5mm.

42. The earphone of claim 32, wherein, In a reference plane perpendicular to the vibration direction, the distance between the centroid of the projection of the second sound hole and the centroid of the projection of the first sound hole is not greater than 5mm.

43. The earphone of claim 32, wherein, In a reference plane perpendicular to the vibration direction, the area ratio of the projection of the second sound hole to the projection of the first sound hole is 0.4-2.

5.

44. The earphone of claim 32, wherein, The first sound hole and / or the second sound hole is a single non-centralized opening.

45. The earphone of claim 32, wherein, The first sound hole and / or the second sound hole is composed of a plurality of small holes arranged in an array.

46. The earphone of claim 45, wherein, In a wearing state, the aperture of the small hole located in the region of the inner side wall directly opposite the external ear canal is greater than the aperture of the small hole located in other regions of the inner side wall.

47. The earphone of claim 32, wherein, The inner side wall is further provided with a sound adjusting hole communicating with the first acoustic cavity.

48. The earphone of claim 47, wherein, The minimum distance between the first sound hole and the sound adjusting hole is not greater than 14mm, the minimum distance from the boundary of the first acoustic cavity to the first sound hole is not greater than 14mm, and the minimum distance from the boundary of the first acoustic cavity to the sound adjusting hole is not greater than 14mm.

49. The earphone of claim 47, wherein, The first sound hole and / or the sound adjusting hole is composed of a plurality of small holes arranged in an array, and the minimum distance between any two adjacent small holes is not greater than 14mm.

50. The earphone of claim 47, wherein, The ratio of the total area of the sound adjusting hole to the total area of the first sound hole is less than 23%.

51. The earphone of claim 47, wherein, The loudspeaker comprises a long axis direction, in which the projection of the first acoustic cavity comprises a first region and a second region arranged along the long axis direction in a reference plane perpendicular to the vibration direction, the projection of the sound adjusting hole in the reference plane is located in the first region, and the projection of the first sound hole in the reference plane is located in the second region.

52. The earphone of claim 51, wherein, The ratio of the length of the first region in the long axis direction to the length of the projection of the first acoustic cavity in the long axis direction is less than 40%.

53. The earphone of any one of claims 32-52, wherein, The frequency response curve of the sound output to the outside of the first shell through the first sound hole has adjacent first and second resonance peaks; wherein the peak resonance frequency of the first resonance peak is less than the peak resonance frequency of the second resonance peak, and the ratio of the peak resonance frequency of the second resonance peak to the peak resonance frequency of the first resonance peak is not less than 3.

54. The earphone of claim 53, wherein, The peak resonance frequency of the first resonance peak is not greater than 300Hz.

55. The earphone of claim 54, wherein, The peak resonance frequency of the second resonance peak is not less than 3.65kHz.

56. The earphone of claim 53, wherein, In the frequency range from the peak resonance frequency of the first resonance peak to the peak resonance frequency of the second resonance peak, the sound pressure level of the sound output by the first sound hole is greater than the sound pressure level of the sound output by the second sound hole.

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