An open earphone

Abstract

An open earphone comprises a sound generating part, the sound generating part comprising a first shell and a loudspeaker arranged inside the first shell; a shell wall of the first shell on a side facing an external ear canal in a wearing state is an inner side wall, the inner side wall is provided with a first sound outlet hole in communication with the loudspeaker, a frequency response curve of sound output to the outside of the first shell through the first sound outlet 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. By setting the ratio of the peak resonance frequencies of the adjacent two resonance peaks in the sound output by the earphone, the width of the flat area of the sound frequency response curve is increased, so that the open earphone has a flat frequency response curve and a small change phase curve in a wider frequency range, which is beneficial to realizing active noise reduction in a wider frequency range.

Description

An open-back headphone

[0001] This application claims priority to Chinese application No. 202410966001.5, filed on July 17, 2024, the contents of which are incorporated herein by reference in part. Technical Field

[0002] This application relates to the field of acoustic technology, specifically to an open-back headphone. Background Technology

[0003] Open-back headphones have become an indispensable tool in people's daily lives and work. As consumers' demands for headphones continue to increase, in addition to having stable output performance, open-back headphones must also be able to reduce environmental noise in noisy or even high-noise environments for normal listening. Therefore, noise cancellation performance has a great impact on the user experience of open-back headphones, so it is necessary to propose an open-back headphone to improve its noise cancellation effect. Summary of the Invention

[0004] The main technical problem this application addresses is to provide an open-back headphone, including a sound-emitting part and an ear hook. The ear hook is configured to place the sound-emitting part near the ear without blocking the ear canal when worn. The sound-emitting part includes a first housing and a speaker disposed inside the first housing. When worn, the shell wall facing the external ear canal is an inner wall. The inner wall has a first sound outlet hole that acoustically connects to the speaker. The frequency response curve of the sound output through the first sound outlet hole to the outside of the first housing has adjacent first and second resonant peaks. The peak resonant frequency of the first resonant peak is less than the peak resonant frequency of the second resonant peak, and the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak is not less than 3.

[0005] In one embodiment, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak is not less than 13.

[0006] In one embodiment, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak is not less than 20.

[0007] In one embodiment, the peak resonant frequency of the first resonant peak is not greater than 300 Hz.

[0008] In one embodiment, the peak resonant frequency of the second resonant peak is not less than 3.65 kHz.

[0009] In one embodiment, the outer wall of the first housing, which is opposite to the inner wall and away from the external auditory canal when the first housing is worn, is the outer wall, and the outer wall is provided with a second sound outlet hole that is acoustically connected to the speaker.

[0010] In one embodiment, within the frequency range from the peak resonant frequency of the first resonant peak to the peak resonant frequency of the second resonant peak, the sound pressure level of the sound output from the first sound outlet is greater than the sound pressure level of the sound output from the second sound outlet.

[0011] In one embodiment, a first acoustic cavity communicating with the first sound outlet is formed between the loudspeaker and the inner sidewall, and a second acoustic cavity communicating with the second sound outlet is formed between the loudspeaker and the outer sidewall.

[0012] In one embodiment, the loudspeaker includes a first diaphragm and a second diaphragm that vibrate synchronously in the same direction; the first diaphragm and the inner sidewall are spaced apart to form a first acoustic cavity, and the sound generated by the first diaphragm in the first acoustic cavity is output through the first sound outlet; the second diaphragm and the outer sidewall are spaced apart to form a second acoustic cavity, and the sound generated by the second diaphragm in the second acoustic cavity is output through the second sound outlet.

[0013] In one embodiment, the loudspeaker further includes a magnetic circuit assembly and a voice coil assembly, the magnetic circuit assembly being disposed between the first diaphragm and the second diaphragm, and the voice coil assembly being disposed through the magnetic gap of the magnetic circuit assembly;

[0014] The voice coil assembly includes a first voice coil and a second voice coil arranged in the vibration direction of the first diaphragm and the second diaphragm and connected by a connector. The end of the first voice coil away from the second voice coil is connected to the first diaphragm, and the end of the second voice coil away from the second voice coil is connected to the second diaphragm. The magnetic circuit assembly cooperates with the voice coil assembly to drive the first diaphragm and the second diaphragm to vibrate synchronously in the same direction.

[0015] In one embodiment, the loudspeaker further includes a support assembly and a voice coil assembly, the support assembly being disposed around the voice coil assembly between the first diaphragm and the second diaphragm; wherein the first diaphragm and the second diaphragm each include a diaphragm, a center mount, and a fixing ring, the diaphragm surrounding the center mount and connected between the center mount and the fixing ring, the center mount being connected to the voice coil assembly, and the fixing ring being connected to the support assembly; the diaphragm is made of one of PU material or silicone material, and the center mount is made of one of magnesium-aluminum alloy, carbon fiber, aluminum-coated polymethacrylamide, and aluminum-coated polyethylene naphthalate.

[0016] In one embodiment, the diaphragm includes a first connecting portion, a folded loop portion surrounding the outer periphery of the first connecting portion, and a second connecting portion surrounding the outer periphery of the folded loop portion; wherein the first connecting portion is connected to the center patch, and the second connecting portion is connected to the fixing ring; in the vibration direction of the first diaphragm and the second diaphragm, the folded loop portion is bent and arched relative to the first connecting portion toward the side away from the voice coil assembly;

[0017] The folded ring portion is divided into a first arc-shaped region, a second arc-shaped region, and a third arc-shaped region in a radial direction perpendicular to the vibration direction. The ratio of the average wall thickness of the first arc-shaped region to the average wall thickness of the second arc-shaped region is not greater than 1.2, and the ratio of the average wall thickness of the third arc-shaped region to the average wall thickness of the second arc-shaped region is not greater than 1.2.

[0018] In one embodiment, the surface on which the first connecting portion connects to the middle patch is defined as the first surface, and the surface on which the second connecting portion connects to the fixing ring is defined as the second surface; in the vibration direction, the distance from the first surface to the plane containing the second surface is the first height, the height from the vertex of the folded ring portion to the plane containing the second surface is the second height, and the ratio of the first height to the second height is not greater than 0.36.

[0019] In one embodiment, the sound-emitting part further includes a limiting component disposed between the speaker and the first housing; the limiting component causes the speaker to be spaced apart from the inner sidewall, and the limiting component also causes the speaker to be spaced apart from the outer sidewall.

[0020] In one embodiment, the limiting component is connected to the speaker; in the arrangement direction of the inner sidewall and the outer sidewall, one end of the limiting component near the inner sidewall elastically abuts against the inner sidewall, and the other end of the limiting component near the outer sidewall elastically abuts against the outer sidewall.

[0021] In one embodiment, the inner sidewall and the loudspeaker form a first acoustic cavity communicating with the first sound outlet, and the inner sidewall is also provided with a tuning hole communicating with the first acoustic cavity.

[0022] In one embodiment, the minimum distance between the first sound outlet and the tuning hole is no greater than 14 mm, the minimum distance from the boundary of the first acoustic cavity to the first sound outlet is no greater than 14 mm, and the minimum distance from the boundary of the first acoustic cavity to the tuning hole is no greater than 14 mm.

[0023] In one embodiment, the first sound outlet and / or the tuning hole are composed of a plurality of small holes arranged in an array, and the minimum distance between any two adjacent small holes is no greater than 14 mm.

[0024] In one embodiment, the ratio of the total area of ​​the tuning aperture to the total area of ​​the first sound outlet aperture is less than 23%.

[0025] In one embodiment, the sound-emitting portion has mutually perpendicular major axis, minor axis, and thickness direction, and the first acoustic cavity is formed in the thickness direction between the loudspeaker and the inner sidewall; on a reference plane perpendicular to the thickness direction, the length of the projection of the first acoustic cavity in the major axis direction is not less than the width in the minor axis direction; wherein, the projection of the first acoustic cavity is divided into a first region and a second region arranged along the major axis direction, the projection of the tuning hole on the reference plane is located in the first region, and the projection of the first sound outlet hole on the reference plane is located in the second region.

[0026] In one embodiment, 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%.

[0027] According to the open-back headphones provided in the above embodiments, by setting the ratio of the peak resonant frequencies of two adjacent resonant peaks in the sound output of the headphones, the width of the flat region of the sound response curve is increased, so that the open-back headphones have a flat frequency response curve and a phase curve with small changes in a wider frequency range, which is beneficial to achieving active noise cancellation in a wider frequency range. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the outline of the front side of the ear as described in this application.

[0029] Figure 2 is a schematic diagram of the wearing state of the headphones when they are worn on the ears according to some embodiments.

[0030] Figure 3 is a schematic diagram of the outer contour structure of the headphones in some embodiments.

[0031] Figure 4 is a schematic diagram of the cross-sectional structure of the sound-generating part in the long axis direction of some embodiments.

[0032] Figure 5 is a schematic diagram of the cross-sectional structure of the sound-generating part in the short axis direction of some embodiments.

[0033] Figure 6 is an exploded view of the structure of the sound-producing part in some embodiments.

[0034] Figure 7 is a schematic diagram of the cross-sectional structure of the sound-generating part in some embodiments (I).

[0035] Figure 8 is a schematic diagram of the frequency response curves corresponding to different sizes of sound outlets in some embodiments.

[0036] Figure 9 is a schematic diagram of the frequency response curves corresponding to the sound outlets at different positions in some embodiments.

[0037] Figures 10A to 10C are schematic diagrams of sound outlets at different locations in some embodiments.

[0038] Figure 11 is a schematic diagram of the frequency response curves corresponding to the first and second sound holes at different relative positions in some embodiments.

[0039] Figures 12A and 12B are schematic diagrams showing the relative positions of the first and second sound outlets in some embodiments.

[0040] Figure 13 is a schematic diagram of the frequency response curves of the first and second sound holes of different sizes in some embodiments.

[0041] Figure 14 is a schematic diagram of first and second sound holes of different sizes in some embodiments.

[0042] Figures 15A and 15B are schematic diagrams of sound outlets with different centroids in some embodiments.

[0043] Figure 16 is a schematic diagram of the frequency response curves corresponding to different shapes of sound outlets in some embodiments.

[0044] Figures 17A and 17B are schematic diagrams of different numbers of sound outlets in some embodiments.

[0045] Figure 18 is a schematic diagram of frequency response curves corresponding to different shapes and numbers of sound outlet holes in some embodiments.

[0046] Figures 19A to 19F are schematic diagrams of sound outlets with different distributions in some embodiments.

[0047] Figure 20 is a schematic diagram of the frequency response curves corresponding to the sound outlets in Figures 19A to 19F.

[0048] Figure 21 is a schematic diagram of the relative distance between the first sound outlet and the tuning hole in some embodiments.

[0049] Figure 22 is a schematic diagram of the frequency response curves corresponding to different distances between any two holes or between any hole and the boundary of the acoustic cavity in Figure 21.

[0050] Figure 23 is a schematic diagram of the frequency response curves of the first sound outlet and the tuning hole in Figure 21 at different area ratios.

[0051] Figure 24 is a schematic diagram showing the relative positions of the first sound outlet and the tuning hole in some embodiments.

[0052] Figure 25 is a schematic diagram of the structure of the sound-generating component in the sound-generating part of some embodiments.

[0053] Figure 26 is an exploded view of the structure of the sound-generating component in some embodiments (I).

[0054] Figure 27 is a schematic cross-sectional view of the sound-generating component in some embodiments.

[0055] Figure 28 is a schematic diagram of the cross-sectional structure of the loudspeaker in some embodiments (I).

[0056] Figure 29 is an exploded view of the speaker structure in some embodiments (I).

[0057] Figure 30 is a schematic diagram of the structure of a voice coil assembly in some embodiments (I).

[0058] Figure 31 is an exploded view of the voice coil assembly in Figure 30.

[0059] Figures 32A and 32B are schematic diagrams of the cross-sectional structure of the loudspeaker from different viewing angles in some embodiments (II).

[0060] Figure 33 is a schematic diagram of the structure of a voice coil assembly in some embodiments (II).

[0061] Figure 34 is a schematic diagram of the cross-sectional structure of the loudspeaker in one embodiment (III).

[0062] Figure 35 is a schematic diagram of the frequency response curve of the loudspeaker in Figure 34.

[0063] Figure 36 is a schematic diagram of the BL curves of loudspeakers corresponding to different sizes of inner and outer magnets in some embodiments.

[0064] Figure 37 is a schematic diagram of the cross-sectional structure of the loudspeaker in some embodiments (IV).

[0065] Figures 38A and 38B are schematic diagrams of the BL curves of loudspeakers corresponding to magnets and conductors of different sizes in Figure 37.

[0066] Figures 39A to 39G are schematic diagrams of different exemplary structures of magnetic circuit components in some embodiments.

[0067] Figure 40 is a schematic diagram of the cross-sectional structure of the loudspeaker in some embodiments (V).

[0068] Figure 41 is a schematic diagram of the cross-sectional structure of the loudspeaker in Figure 40 from another perspective.

[0069] Figure 42 is an exploded view of the speaker structure in Figure 40.

[0070] Figure 43 is a schematic diagram of the driving force coefficient of the loudspeaker corresponding to different sizes of through holes in some embodiments.

[0071] Figure 44 is a schematic diagram of the cross-sectional structure of the loudspeaker in some embodiments (V).

[0072] Figure 45A is an exploded view of the speaker structure in some embodiments (II).

[0073] Figure 45B is a cross-sectional view of the loudspeaker in Figure 45A along its short axis.

[0074] Figure 45C is a cross-sectional view of the loudspeaker in Figure 45A along its long axis.

[0075] Figure 46A is an exploded view of the speaker structure in some embodiments (III).

[0076] Figure 46B is an exploded view of the speaker structure in some embodiments (IV).

[0077] Figure 47A is a schematic diagram of the structure of a loudspeaker with a magnetic circuit fixing ring in some embodiments (I).

[0078] Figure 47B is a structural schematic diagram of the speaker in Figure 47A from another perspective.

[0079] Figure 48A is a schematic diagram of the structure of a loudspeaker with a magnetic circuit fixing ring in some embodiments (II).

[0080] Figure 48B is a structural schematic diagram of the speaker in Figure 48A from another perspective.

[0081] Figure 49 shows a schematic diagram of the diaphragm assembly in some examples.

[0082] Figure 50 is a magnified schematic diagram of a partial structure of the diaphragm assembly in Figure 49.

[0083] Figure 51 is a schematic diagram of the bonding area and the width of the fold in the diaphragm assembly in some embodiments.

[0084] Figure 52 is a schematic diagram of the BLx curve when the loudspeaker uses the diaphragm assembly in Figure 50 in some embodiments.

[0085] Figure 53 is a schematic diagram of the KMs curves of the speaker in some embodiments with different ratios of the connection area and the width of the surround.

[0086] Figure 54 is a schematic diagram of the diaphragm ring width and thickness of the diaphragm assembly in some embodiments.

[0087] Figure 55 is a schematic diagram of the KMs curves of the loudspeaker in some embodiments with different ratios of surround width and thickness.

[0088] Figure 56 is a schematic diagram of the height difference between the two ends of the diaphragm collar and the collar width in some embodiments of the diaphragm assembly.

[0089] Figure 57 is a schematic diagram of the KMs curves of the speaker at different ratios of the height difference at both ends of the surround to the surround width in some embodiments.

[0090] Figure 58 is a schematic diagram of the height difference between the two ends of the diaphragm ring and the arch height of the diaphragm ring in some embodiments.

[0091] Figure 59 is a schematic diagram of the KMs curves of the speaker at different ratios of the height difference between the two ends of the surround and the arch height in some embodiments.

[0092] Figure 60 is a schematic diagram of the diaphragm thickness partitioning of the diaphragm assembly in some embodiments.

[0093] Figure 61 is a schematic diagram of the KMs curves of the loudspeaker in different thickness regions of the surround at different ratios in some embodiments.

[0094] Figure 62 is a schematic cross-sectional view of the diaphragm assembly in some embodiments.

[0095] Figure 63 shows the frequency response curves of headphones with different diaphragms in some embodiments. Detailed Implementation

[0096] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0097] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0098] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0099] 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 12, the cymba concha 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 12, the cymba concha 13, and the triangular fossa 14 have a certain volume and depth in three-dimensional space, and the concha 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 12.

[0100] Since the external auditory canal 11, concha 12, concha cymba 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 application can achieve stable wearing of the headphones by means of one or more physiological parts of the ear.

[0101] 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).

[0102] By utilizing parts of the ear other than the external auditory canal 11, the earphone can be worn and sound can be transmitted. This not only "liberates the external auditory canal" and reduces the impact of earphones on the user's ear health, but also effectively improves the user experience. For example, when a user wears earphones on the road, the earphones will not block the external auditory canal 11. This allows the user to receive both the sound from the earphones and ambient sounds (such as horns, car bells, voices of people around, traffic signals, etc.), thereby effectively reducing the occurrence of traffic accidents.

[0103] 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.

[0104] 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.

[0105] It should be noted that in fields such as medicine and anatomy, the human body can be defined by three basic planes: the sagittal plane, the coronal plane, and the horizontal plane, as well as three basic axes: the sagittal axis, the coronal axis, and the vertical axis.

[0106] In this context, 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 lateral direction of the body, dividing the body into anterior and posterior parts; and 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 lateral 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.

[0107] 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.

[0108] 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.

[0109] For open-back headphones, when worn, the sound-producing part of the headphones usually cannot form a relatively closed sound transmission channel with the external ear canal 11, which will cause environmental noise to enter the external ear canal 11 and have a significant impact on the user's hearing.

[0110] In order to reduce or cancel environmental noise in noisy or even high-noise environments, thereby realizing the active noise cancellation function of headphones and improving the listening effect of headphones; please refer to Figures 2 and 3. Some embodiments of this application provide an open-back headphone (hereinafter referred to as headphones), including a sound-emitting part 100 and an ear hook; wherein, the ear hook is configured to place the sound-emitting part 100 near the ear but not block the external auditory canal 11 when worn. It should be noted that, due to individual differences among different users, when the headphones are worn by different users, the sound-emitting part 100 may partially cover the external auditory canal 11, but the external auditory canal 11 is still not blocked; this is explained in detail below.

[0111] In some embodiments, referring to Figures 4 to 6, the sound-emitting part 100 includes a first housing 110, a sound-emitting component, and a microphone component, etc. The sound-emitting component is disposed inside the first housing 110 and may include a speaker 120 and a limiting component 130. The speaker 120 can convert electrical signals into corresponding mechanical vibrations to generate 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, thereby eliminating ambient noise near the external auditory canal 11 and achieving 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 experience.

[0112] The limiting component 130 is used to position and confine the speaker 120 inside the first housing 110. On the one hand, by placing the speaker 120 inside the first housing 110, the sound generated by the speaker 120 can be stably output to the outside of the first housing 110 through the acoustic hole provided in the first housing 110. On the other hand, by confining the speaker 120, the speaker 120 can be prevented from shaking relative to the first housing 110 when vibrating, thereby ensuring the sound output performance of the sound-emitting part 100.

[0113] The microphone component can collect sound signals, such as user voice and ambient sounds. For example, based on the ambient noise collected by the microphone, 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.

[0114] In some embodiments, please refer to Figures 2 and 3. 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 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.).

[0115] For example, referring to Figure 3, 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 part of the battery section 200 (e.g., the part occupied by the battery assembly and the circuit board assembly) is hung between the auricle and the head, and the other part of the battery section 200 extends towards the side of the auricle away from the head and connects to the adapter section 300, so that the sound-generating section 100 is worn near the external auditory canal 11 without blocking the external auditory canal 11, so that the earphone is an open-back earphone. Furthermore, the battery assembly and circuit board assembly can be provided in the battery section 200, and the adapter section 300 can be provided with earphone buttons and an adapter plate for electrically connecting the circuit board assembly to the speaker 120 and the microphone assembly, etc.

[0116] 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.

[0117] 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 ear by means of suspension, clamping, etc.

[0118] Given that most existing open-back headphones with active noise cancellation only support active noise cancellation within a narrow frequency band, in order to enable headphones to have a flatter output across a wider frequency band, thereby effectively enhancing the active noise cancellation effect of headphones in open-back application scenarios, the following mainly introduces the sound-generating part 100.

[0119] Referring to Figures 3 to 6, 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). (e.g., when the projection shape is rectangular or approximately rectangular, the major axis direction is the length direction of the rectangle or approximately rectangular shape). 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 shape). 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 in an inclined state while being worn, 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 inclined 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 inclined. 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 102. 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 102 on the sagittal plane.

[0120] Referring to Figure 6, 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, and a lower sidewall 110d. 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 110 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 110 close to the top of the head in the short axis direction when worn; and 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. It is understood that these multiple different housing walls can collectively form a receiving cavity for the sound-emitting part 100, and the sound-emitting assembly (e.g., the speaker 120) is housed within this receiving cavity.

[0121] In some embodiments, referring to Figures 4 to 24, inside the first housing 110, a first acoustic cavity 111-1 is formed between the speaker 120 and the inner sidewall 110a, and a second acoustic cavity 111-2 is formed between the speaker 120 and the outer sidewall 110b; correspondingly, the inner sidewall 110a is provided with a first sound outlet 112-1 that is acoustically connected to the speaker 120 through the first acoustic cavity 111-1, and the outer sidewall 110b is provided with a second sound outlet 112-2 that is acoustically connected to the speaker 120 through the second acoustic cavity 111-2.

[0122] For example, in some embodiments, the loudspeaker 120 may be a dual-diaphragm loudspeaker, which includes a first diaphragm 121-1 and a second diaphragm 121-2 disposed opposite to each other in the vibration direction; wherein the first diaphragm 121-1 and the inner sidewall 110a are disposed opposite to each other in the vibration direction (i.e., the thickness direction) to form a first acoustic cavity 111-1, and the second diaphragm 121-2 and the outer sidewall 110b are disposed opposite to each other in the vibration direction to form a second acoustic cavity 111-2.

[0123] Firstly, 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 sound outlet 112-1 and the second sound outlet 112-2 serve as the neck of their respective Helmholtz resonant cavity models. When the speaker 120 vibrates and outputs sound, adjusting the pressure inside the sound-emitting part 100 based on the second Helmholtz resonant cavity model can adjust the frequency response curve of the sound output through the first sound outlet 112-1. For example, the sound output through the first sound outlet 112-1 can have a flat frequency response curve and a phase curve with small changes in amplitude over a wider frequency range, which is beneficial for the headphones to achieve active noise cancellation over a wider frequency range.

[0124] For example, in some embodiments, the frequency response curve of the sound output through the first sound outlet 111-1 has an adjacent first resonance peak and a second resonance peak. The peak resonant frequency of the first resonance peak is less than the peak resonant frequency of the second resonance peak. With the cooperation of the second Helmholtz resonant cavity, the peak resonant frequency of the second resonance peak and the peak resonant frequency of the first resonance peak can be set to be no less than 3, thereby effectively increasing the width of the flat area of ​​the frequency response curve of the sound output through the first sound outlet 112-1, providing support for the headphones to perform active noise cancellation in a wider frequency range.

[0125] Secondly, when using a dual-diaphragm speaker, the relatively stable vibration of the dual-diaphragm speaker and the good consistency of vibration between the first diaphragm 121-1 and the second diaphragm 121-2, combined with the corresponding sound outlet and acoustic cavity, allow the first resonant peak to shift as low as possible and the second resonant peak to shift as high as possible. This helps to increase the width of the flat region of the frequency response curve of the headphone output sound, thereby providing support for active noise cancellation in a wider frequency range. Simultaneously, when the first diaphragm 121-1 and the second diaphragm 121-2 vibrate in the same direction, the combination of the first sound outlet 112-1 and the second sound outlet 112-2 can also significantly increase the effective area of ​​sound output and improve sound output efficiency.

[0126] Thirdly, when worn, at least a portion of the first housing 110 can be located within the concha 12. The inner wall 110a cooperates with the concha 12 to form an auxiliary cavity communicating with the external auditory canal 11. This auxiliary cavity is usually in a semi-open state, and the first sound outlet 112-1 is located within the auxiliary cavity. In this way, the sound output through the first sound outlet 112-1 can be focused by the limitation of the auxiliary cavity. Most of the sound will propagate into the external auditory canal 11, while a small portion of the sound propagating outside the external auditory canal 11 (such as noise-canceling sounds) can be canceled out by the ambient noise near the external auditory canal 11. This not only helps to improve the listening effect and enhance the active noise cancellation effect, but also helps to reduce the problem of sound leakage.

[0127] 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. 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 active noise cancellation effect of the headphones.

[0128] In some embodiments, the peak resonant frequency of the first resonant peak of the sound output from the first sound outlet 112-1 can be set to no more than 300Hz; the peak resonant frequency of the second resonant peak can be set to no less than 1kHz, such as no less than 3.65kHz, no less than 4.5kHz, no less than 5.8kHz, no less than 6.7kHz, no less than 7.5, no less than 7.75, no less than 8.75, no less than 9.25, no less than 9.5, etc. In this way, the sound output from 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 a small change amplitude in a wider frequency range, which is beneficial for the headphones to achieve active noise cancellation in a wider frequency range.

[0129] Since the high-frequency resonant peak of the frequency response curve of the headphone output is mainly affected by the high-frequency peak of the speaker 120 itself and the high-frequency peak formed in the acoustic cavity, in some embodiments, by designing the number, shape, size, and position of the speaker 120 (e.g., magnetic circuit, voice coil, diaphragm, and their structural relationships) and one or more acoustic structures (e.g., sound outlet, acoustic cavity), the frequency response curve of the headphone (specifically, the first sound outlet 112-1) can be optimized to make the flat area of ​​the frequency response curve wider, thereby supporting active noise cancellation of the headphone in a wider frequency range; this will be explained in detail below.

[0130] As above, the following will further describe the sound-emitting part 100 provided in some embodiments of this application from the perspectives of the size, shape, position, and number of sound outlet holes (it should be noted that the high-frequency resonance peak, high-frequency peak, etc. mentioned below can be understood as the second resonance peak of the sound output through the first sound outlet hole 112-1 in some embodiments).

[0131] Please refer to Figure 8, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to different sizes of the first sound outlet 112-1 and the second sound outlet 112-2 according to some embodiments of this application. It should be noted that Figure 8 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.

[0132] In Figure 8, 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 wall 110a and outer wall 110b.

[0133] As shown in Figure 8, 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.

[0134] Based on this, in some embodiments, referring to Figures 10A to 10C, as well as Figures 15A and 15B, the first sound outlet 112-1 and the second sound outlet 112-2 can adopt a single-hole structure; when the length of the first housing 110 and the sound outlet in the major axis direction is greater than their respective width in the minor 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 major axis direction to the length of the inner sidewall 110a in the major axis direction can be not less than 0.3, and the ratio of the length of the first sound outlet 112-1 in the major axis direction to the length of the outer sidewall 110a in the major axis direction can be not less than 0.3. When the outline shape of the sound-emitting part 100 is a circular isocentric symmetrical geometry, the ratio of the radius of the sound outlet to the radius of the corresponding sidewall of the first housing 110 can be not less than 0.3. In this way, the resonant frequency of the corresponding acoustic cavity can be no less than 1kHz, ensuring that the second resonant peak of the sound output through the sound outlet shifts to the high frequency range, ultimately enabling the headphones to have a flatter output over a wider frequency range and improving the active noise cancellation effect of the headphones in open environments with greater ambient noise.

[0135] Please refer to Figure 9, which is a schematic diagram of the frequency response curves corresponding to the sound outlets at different positions according to some embodiments of this application. It should be noted that Figure 9 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, and that their dimensions and positions are the same.

[0136] In Figure 9, the sound outlets corresponding to curves L441, L442, L443, and L444 are all eccentrically positioned along the long side of the surface of the first housing 110. Curve L441 indicates that the distance between the center of the sound outlet and the center of the corresponding sidewall in the length direction is 1 mm; curve L442 indicates that the distance between the center of the sound outlet and the center of the corresponding sidewall in the length direction is 3 mm; curve L443 indicates that the distance between the center of the sound outlet and the center of the corresponding sidewall in the length direction is 5 mm; and curve L444 indicates that the distance between the center of the sound outlet and the center of the corresponding sidewall in the length direction is 0 mm, meaning that the sound outlet is not eccentrically positioned and is located at the center of the corresponding sidewall of the first housing 110.

[0137] As shown in Figure 9, 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.

[0138] Based on this, in some embodiments, referring to Figure 10A, 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 110a, and the centroid of the second sound outlet 112-2 coincides with the center of the outer sidewall 110b, so that the sound outlet is located at the center of the corresponding sidewall of the first housing 110. 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.

[0139] As shown in Figure 9, 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 high-frequency peak position of the headphones.

[0140] 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 10B, the first sound outlet 112-1 can be off-center in the length direction relative to the center of the inner sidewall 110a; please refer to Figure 10C, the first sound outlet 112-1 can be off-center in the width direction relative to the center of the inner sidewall 110a; 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 110a.

[0141] Please refer to Figure 11, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to the first sound outlet 112-1 and the second sound outlet 112-2 arranged in different positions according to some embodiments of this application. It should be noted that Figure 11 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 size.

[0142] In Figure 11, curve L461 represents the frequency response curve of 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 of 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 of 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 of 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 11, 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.

[0143] Based on this, in some embodiments, referring to Figure 12A, 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; this allows the sound-emitting part 100 or the headphones to have a relatively flat output over a wider frequency range, improving the active noise cancellation effect of the headphones. In other embodiments, referring to Figure 12B, 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.

[0144] 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 ensure that 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 is located in a higher frequency range, while the peak resonant frequency of the resonant peak of the sound output from the second sound outlet 112-2 is lower than the peak resonant frequency of the second resonant peak of the sound output from the first sound outlet 112-1, so that the headphones have a flatter output over a wider frequency range.

[0145] For example, an acoustic barrier, such as one or more of steel mesh, gauze, or waterproof and breathable membrane, is 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, the peak and valley of the second resonant peak are suppressed, which can ensure a large output in the low frequency range and 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 active noise reduction effect.

[0146] Due to limitations in the actual manufacturing process and 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, which may affect the output of the headphones and consequently affect the headphones' active noise cancellation performance against larger ambient noise in open environments.

[0147] Figure 13 is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to different sizes of the first sound outlet 112-1 and the second sound outlet 112-2 according to some embodiments of this application. It should be noted that Figure 13 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 of the same shape (for example, the short side dimension of the sound outlet is half the long side dimension) and they are arranged directly opposite each other.

[0148] In Figure 13, 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 given when the ratio of the long side dimension of the corresponding surface of the first housing 110 to that of the first housing 110 is 0.5, and the ratio of the long side dimension of the second sound outlet 112-2 to that 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 that 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 that 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.

[0149] As shown in Figure 13, 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 around 10kHz, while the high-frequency resonance peak of curve L484 is located around 5kHz. Curve L483 has a peak and valley around 6kHz, which affects the output of the sound-generating 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-generating part 100 is improved.

[0150] 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.

[0151] In other embodiments, please refer to Figure 14. In order to meet the design needs and appearance requirements of various components of the headphones, and when it is necessary to set the size of the first sound outlet 112-1 and the size of the second sound outlet 112-2 to be different, 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, so that the peak resonant frequency of the sound output from the first sound outlet 112-1 is located in a higher frequency band. At this time, the peak resonant frequency of the sound output from the second sound outlet 112-2 can be smaller than the peak resonant frequency of the sound output from the first sound outlet 112-1.

[0152] 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 sound output from the second sound outlet 112-2 through the acoustic barrier, the peak and valley of the high-frequency resonance peak of the sound are suppressed. This ensures a large output in the low-frequency range and prevents 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 active noise reduction effect.

[0153] Please refer to Figures 15A, 15B, and 16; wherein, Figures 15A and 15B are schematic diagrams of sound outlets with different centroids according to some embodiments of the present application, and Figure 16 is a schematic diagram of the frequency response curves of loudspeakers corresponding to sound outlets of different shapes according to some embodiments of the present application; in Figure 16, 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 15A, 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., an annular opening) as shown in Figure 15B.

[0154] 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 area ratio of the first sound outlet 112-1 to the inner wall surface 110a. Both single concentrated opening and single non-concentrated opening can be understood as the corresponding sound outlet adopting a single hole structure.

[0155] As shown in Figure 16, 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 15B, 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.

[0156] Please refer to Figures 17A, 17B, and 18; Figures 17A and 17B are schematic diagrams showing different numbers of sound outlet holes according to some embodiments of this application; wherein the total opening area of ​​the sound outlet holes shown in Figures 17A and 17B is the same, that is, the opening ratio is the same. Figure 18 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different opening shapes and different numbers of sound outlet holes according to some embodiments of this application. In Figure 18, curve L521 represents the frequency response of the sound-emitting part 100 corresponding to a single concentrated opening hole with an opening ratio of 0.25; curve L522 represents the frequency response of the sound-emitting part 100 corresponding to a non-single concentrated opening hole, a large mesh opening hole, and an opening ratio of 0.2178 as shown in Figure 17A; curve L523 represents the frequency response of the sound-emitting part 100 corresponding to a non-single concentrated opening hole, a small mesh opening hole, and an opening ratio of 0.1657 as shown in Figure 17B.

[0157] Please refer to Figure 18 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 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 centralized opening distribution as shown in Figures 17A and 17B, that is, the sound outlets are a porous structure composed of multiple small holes arranged in an array; this can make the high-frequency peak of the speaker 120 higher, and can also significantly increase the effective area of ​​sound output, ensuring the active noise reduction effect, while also meeting the appearance design requirements of the sound-emitting part 100 or headphones.

[0158] Please refer to Figure 18 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.

[0159] Please refer to Figures 19A to 19F, which are schematic diagrams of sound outlets with different distributions of non-single concentrated openings according to some embodiments of this application. Specifically, Figure 19A 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 19B 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 19C 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 19D 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 on the other side along the long axis has pressure relief holes. The opening ratio of the sound outlet holes is 0.15, and the opening ratio of the pressure relief holes is 0.0375. Figure 19E 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 19F 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. In this case, 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.

[0160] Please refer to Figure 20, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to different distributions of non-single concentrated openings of sound-emitting holes according to some embodiments of this description. Curve L541 corresponds to the non-single concentrated openings of sound-emitting holes that are annularly distributed across 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 19B; curve L543 corresponds to the first housing 110 with a fully open corresponding side wall, with an opening ratio of 1; curve L544 corresponds to the sound-emitting hole shown in Figure 19D; curve L545 corresponds to the sound-emitting hole shown in Figure 19E; curve L546 corresponds to the sound-emitting hole shown in Figure 19F; and curve L547 corresponds to the speaker 120 without a first housing 110.

[0161] Please refer to Figure 20. 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.

[0162] 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, 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 inner sidewall 110a is no less than 10%.

[0163] 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.

[0164] 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 housing 110 (e.g., the part of the inner sidewall 110a 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.

[0165] Therefore, in some embodiments, referring to Figures 6, 19D, 21, and 24, the inner sidewall 110a is also provided with a through-hole 113-3, which communicates with the first acoustic cavity 111-1. Based on the communication relationship between the first sound outlet 112-1 and the through-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 via the through-hole 113-3 can be adjusted. For example, the peak resonant frequency of the second resonant peak is not less than 1kHz. In this case, 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).

[0166] 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.

[0167] 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 of the resonant peak. Referring to Figure 21, taking an example where both the first sound outlet 112-1 and the tuning port 113-3 adopt 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.

[0168] Please refer to Figure 22, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to different L1-X and L2-X according to some embodiments of this description. In Figure 6, LM is 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).

[0169] As shown in Figure 22, 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. Referring to Figure 6, it can be seen that as the LM increases, the corresponding high-frequency peak shifts forward, which means the opening area decreases accordingly, leading to a decrease in the sound pressure level output from the inner wall 110a side. When LM = 14mm, compared to other smaller LMs, the sound pressure level at 1kHz decreases by 3dB, which is acceptable.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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, please refer to FIG23, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 under different area ratios of the tuning hole 113-3 and the first sound outlet hole 112-1 according to some embodiments of this description. In the figure, 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.

[0174] As shown in Figure 23, as SS gradually increases, the high-frequency peak gradually moves 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 23, 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.

[0175] 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.

[0176] 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.

[0177] In some embodiments, referring to Figure 24, 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 farther 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.

[0178] 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 is divided into a first region and a second region along its length. 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 port 113-3 on the reference plane is located within the first region, and the projection of the first sound outlet port 112-1 on the reference plane is located within the second region.

[0179] Thus, by placing the tuning hole 113-3 and the first sound outlet hole 112-1 in different areas of the inner wall 110a 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.

[0180] It should be noted that the bold dashed lines in Figures 21 and 24 represent the projection boundary of the first acoustic cavity 111-1 on the reference plane; the bold solid lines with arrows in Figure 24 represent 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 bold solid line represents the first region, and the region to the right of the bold solid line represents the second region.

[0181] In some embodiments, referring to Figures 21 and 24, 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 110a directly in front of the external auditory canal 11 is set to be larger than the diameter of the small holes located in other areas of the inner wall 110a when worn. For example, among the multiple small holes in 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 earphone directly in front of the external auditory canal 11 can be increased, thereby ensuring the user's listening effect.

[0182] As described in some of the embodiments above, by setting 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 improving the active noise cancellation effect. In some embodiments, an acoustic barrier can also be set 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).

[0183] 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.

[0184] As described in some of the preceding embodiments, the sound-generating assembly may include a loudspeaker 120 and a limiting assembly 130. The limiting assembly 130 can be used to position and confine the loudspeaker 120 within the first housing 110. Furthermore, the limiting assembly 130 can also be used to cooperate with the loudspeaker 120 to form an acoustic cavity between the corresponding housing sidewalls 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.

[0185] The limiting component 130 not only affects the structural relationship between the speaker 120 and the first housing 110, but also the structure of the acoustic cavity, thereby affecting the active noise cancellation of the headphones over a wide frequency range. Therefore, please refer to Figures 5 to 6 and Figures 25 to 27. The following mainly describes the limiting component 130 and its related structures.

[0186] In some embodiments, referring to FIG5, the loudspeaker 120 includes a first diaphragm 121-1 and a second diaphragm 121-2 spaced vertically along the vibration direction, and a limiting component 130 is connected between the loudspeaker 120 and the first housing 110. Exemplarily, a portion of the limiting component 130 connects the loudspeaker 120 to the inner sidewall 110a of the first housing 110, and another portion connects the loudspeaker 120 to the outer sidewall 110b of the first housing 110.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] In some embodiments, the limiting component 130 is fixedly connected to the speaker 120 to form an integral structure; 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 disassembling and assembling the sound-emitting part 100.

[0191] In some embodiments, referring to Figures 25 to 27, the limiting component 130 includes a second housing, a first sealing ring 131, and a second sealing ring 132. The speaker 120 is disposed within the second housing and is sealed and connected to the second housing. For ease of distinction and description, the shell wall of the second housing that is spaced apart from the inner sidewall 110b 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. It can also be understood that the first transverse sidewall is disposed in the first acoustic cavity 111-1 facing the inner sidewall 110a (or speaker 120), and the second transverse sidewall is disposed in the second acoustic cavity 111-2 facing the outer sidewall 110b (or speaker 120), and the speaker 120 is located between the first transverse sidewall and the second transverse sidewall in the vibration direction. In addition, 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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 projections of the first sound outlet 112-1 and the first sound guide 130-1 on a reference plane perpendicular to the vibration direction has a projected area not less than 80% of the projected area of ​​the first sound guide 130-1. This arrangement allows the air pushed by the diaphragm in the sound guide of the limiting component 130 to be smoothly pushed out from the first sound outlet 112-1, ensuring the acoustic output of the speaker 120 and providing support for shifting the peak resonant frequency of the first resonant peak of the sound output from the first sound outlet 112-1 as low as possible and the peak resonant frequency of the second resonant peak as high as possible. Preferably, in some embodiments, the projection of the second sound outlet 112-2 falls within the projection of the second sound guide 130-2 on a 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 sound outlet 112-2 and the projection of the second sound guide 130-2 has a projected area not less than 80% of the projected area of ​​the second sound guide 130-2. This arrangement allows the air pushed by the diaphragm in the sound guide 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.

[0196] 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.

[0197] Additionally, referring to Figure 5, 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 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.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] In some embodiments, referring to Figures 25 to 27, 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.

[0203] 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.

[0204] 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.

[0205] In some embodiments, the limiting component 130 may omit the second housing, and a sealed 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.

[0206] 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.

[0207] 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.

[0208] In some embodiments, referring to Figure 6, 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] In some embodiments, please refer to Figures 25 and 26. 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.

[0214] 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.

[0215] 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 hole, so as to adjust 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 hole into a mesh hole structure. On the other hand, the acoustic barrier can be fixed to the corresponding rib structure 130-3 and the corresponding side wall of the limiting component 130 by means of bonding, welding or other methods, so as to avoid the acoustic barrier from shaking due to air vibration when the speaker 120 is working, thereby avoiding adverse effects on the sound output (such as frequency response curve, etc.) and ensuring the active noise reduction effect.

[0216] In some embodiments, referring to FIG27, 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.

[0217] 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.

[0218] 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.

[0219] 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.

[0220] In some embodiments, referring to FIG27, the first and second transverse sidewalls each have a central portion and an arcuate portion surrounding the central portion, and the 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.

[0221] 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, a second clearance space 130-6 can also 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.

[0222] 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.

[0223] As in some of the aforementioned embodiments, the loudspeaker 120 may be a dual-diaphragm loudspeaker. Please refer to Figures 27, 29, 34, 50 to 51B, 40 to 42, and 45A to 47B. The loudspeaker 120 includes a first diaphragm 121-1, a second diaphragm 121-2, a magnetic circuit assembly, a voice coil assembly, etc. The first diaphragm 121-1 and the second diaphragm 121-2 are spaced apart and opposite each other in the vibration direction. The voice coil assembly and the magnetic circuit assembly are arranged between the first diaphragm 121-1 and the second diaphragm 121-2. At least a portion of the voice coil assembly extends into the magnetic gap of the magnetic circuit assembly, and at least one of the first diaphragm 121-1 and the second diaphragm 121-2 is connected to the voice coil assembly. This allows the voice coil assembly to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction, thereby generating sound, through the cooperation of the magnetic circuit assembly and the voice coil assembly.

[0224] Therefore, by having the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously in the same direction, the consistency and stability of the speaker 120 vibration are improved. This helps the peak resonant frequency of the low-frequency resonant peak (e.g., the first resonant peak) of the headphone output to shift to a lower frequency band and the peak resonant frequency of the high-frequency resonant peak (e.g., the second resonant peak) to a higher frequency band, thereby enabling the headphone to have a flatter output over a wider frequency range, thus enhancing the active noise cancellation effect.

[0225] Considering that, in addition to structural features such as the sound outlet and tuning port, the structure and performance of the speaker 120 itself also have a crucial impact on the active noise cancellation of the headphones; for example, the first diaphragm 121-1 and the second diaphragm 121-2 can be indirectly connected through the voice coil assembly, and the first diaphragm 121-1 and the second diaphragm 121-2 can also be directly connected while being connected through the voice coil assembly. This can ensure the consistency of the synchronous and co-directional vibration of the two diaphragms, thereby providing support for enhancing the active noise cancellation effect.

[0226] The following mainly introduces the relevant structure of the dual-diaphragm loudspeaker 120 when the first diaphragm 121-1 and the second diaphragm 121-2 are indirectly connected through a voice coil assembly.

[0227] In some embodiments, referring to Figures 30 to 38B and 44 to 46B, the voice coil assembly includes a first voice coil 123-1 and a second voice coil 123-2, which are arranged vertically in the vibration direction. The end of the first voice coil 123-1 away from the second voice coil 123-2 is connected to a first diaphragm 121-1, and the end of the second voice coil 123-2 away from the first voice coil 123-1 is connected to the second diaphragm 121-2. The first voice coil 123-1 drives the first diaphragm 121-1 to vibrate, and the second voice coil 123-2 drives the second diaphragm 121-2 to vibrate, causing the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction.

[0228] Exemplarily, in some embodiments, the first voice coil 123-1 and the second voice coil 123-2 are connected at their ends that are close to each other in the vibration direction. The voice coil assembly also includes a connector (for ease of distinction and description, this connector is defined as the first connector 127), which connects the first voice coil 123-1 and the second voice coil 123-2; alternatively, the first voice coil 123-1 and the second voice coil 123-2 can be directly bonded together using adhesive or similar methods. In this case, the structural connection between the first voice coil 123-1 and the second voice coil 123-2 is equivalent to constructing an integrated voice coil assembly, thereby achieving an indirect connection between the first diaphragm 121-1 and the second diaphragm 121-2.

[0229] Firstly, the first diaphragm 121-1 and the second diaphragm 121-2 are connected by an integrated voice coil assembly, allowing the first voice coil 123-1 and the second voice coil 123-2 to share a magnetic circuit assembly. With the cooperation of the magnetic circuit assembly, the consistency of vibration of the first diaphragm 121-1 and the second diaphragm 121-2 (i.e., synchronous and co-directional vibration) can be ensured, and the driving force of the voice coil assembly can be enhanced. This is beneficial for the headphones to have a flatter output over a wider frequency range, ensuring the active noise cancellation effect.

[0230] Secondly, when the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously and in the same direction, the volume of the common cavity 111-3 formed between the two will not change with the vibration of the diaphragms. The gas in the common cavity 111-3 will not only not hinder the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, but the gas can also move back and forth with the vibration of the two diaphragms as an accompanying mass. This is beneficial to improving the consistency of the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, thereby improving the output performance of the headphones and ensuring the effect of active noise cancellation of the headphones.

[0231] Thirdly, the connection between the first voice coil 123-1 and the second voice coil 123-2 can ensure the consistency of vibration between the first diaphragm 121-1 and the second diaphragm 121-2, and can also flexibly adjust the winding direction of the voice coil coil and the direction of the working current, so that the voice coil assembly can use the magnetic field distribution of the magnetic circuit assembly.

[0232] Fourth, in scenarios where headphones have high waterproofing requirements, such as headphones worn while swimming, the first housing 110 often needs to be fully sealed. In this case, if the first diaphragm 121-1 and the second diaphragm 121-2 vibrate in opposite directions, the gas in the common cavity 111-3 formed between the first diaphragm 121-1 and the second diaphragm 121-2 will be difficult to expel. This will interfere with the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, thereby affecting the output performance of the headphones. Therefore, using the first voice coil 123-1 and the second voice coil 123-2 to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction can support the full sealing treatment of the first housing 110 or the speaker itself.

[0233] In some embodiments, referring to Figures 27, 29 and 37, the magnetic circuit assembly includes an outer magnetic circuit component 122-1, an inner magnetic circuit component 122-2 and a magnetic circuit connector 122-3; wherein, the outer magnetic circuit component 122-1 surrounds the outer periphery of the inner magnetic circuit component 122-2 and is connected to the inner magnetic circuit component 122-2 through the magnetic circuit connector 122-3, thereby forming a magnetic gap of the magnetic circuit assembly between the outer magnetic circuit component 122-1 and the inner magnetic circuit component 122-2.

[0234] Accordingly, referring to Figures 30 and 31, the first voice coil 123-1 and the second voice coil 123-2 can adopt an unequal diameter structure. For example, on a reference plane perpendicular to the vibration direction, there is 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 major axis direction or the minor axis direction. This results in a portion of the first voice coil 123-1 and the second voice coil 123-2 that are connected to each other and another portion that is separated from each other, thus allowing the gap between them to be used as a basis for... The presence of the first voice coil 123-1 and the second voice coil 123-2 forms a clearance channel 123-3 that allows the magnetic circuit connector 122-3 to pass through the voice coil assembly; 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 a clearance channel 123-3 at the separation of the first voice coil 123-1 and the second voice coil 123-2.

[0235] For example, referring to Figure 30, 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 in the long axis direction can be defined as long sidewalls, and the sidewalls in the short axis direction 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. In this way, a clearance channel 123-3 can be formed between the short sidewall of the first voice coil 123-1 and the short sidewall of the second voice coil 123-2.

[0236] For example, 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 the first connector 127, so that the orthographic projection of the first voice coil 123-1 on the reference plane is the first ring, and the orthographic projection of the second voice coil 123-2 on the reference plane is the second ring. In the case that the first ring and the second ring have different diameters, the third connector is used to realize the partial connection and partial separation between the first voice coil 123-1 and the second voice coil 123-2, thereby forming the avoidance channel 123-3.

[0237] Thus, 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 connector 122-3. This is equivalent to placing the voice coil assembly within the same magnetic gap of the magnetic circuit assembly. This not only enhances the structural stability of the magnetic circuit assembly itself, supporting the rapid assembly of the speaker 120, but also helps reduce assembly difficulty and cost, and avoids the voice coil assembly from touching the magnetic circuit assembly during movement, thus preventing it from affecting the sound output. At the same time, the outer magnetic circuit component 122-1 adopts a ring structure surrounding the inner magnetic circuit component 122-2, which allows the magnetic circuit assembly to have a larger design size. By increasing the volume of the magnet, the driving force of the voice coil assembly can be increased, thereby improving the sound output performance of the speaker 120.

[0238] In some embodiments, referring to FIG30, the overall outer contour shape of the loudspeaker 120 is set to a rectangle, racetrack shape, or ellipse, etc., that matches the contour shape of the first housing 110 or the sound-emitting part 100. In this case, the length of the long sidewall of the first voice coil 123-1 in the long axis direction is greater than the width of the short sidewall of the first voice coil 123-1 in the short axis direction, and the length of the long sidewall of the second voice coil 123-2 in the long axis direction is greater than the width of the short sidewall of the second voice coil 123-2 in the short axis direction. At the same time, the length of the long sidewall of the first voice coil 123-1 in the long axis direction can be set to be less than the length of the long sidewall of the second voice coil 123 in the long axis direction. In this case, the long sidewall of the first voice coil 123-1 and the short sidewall of the second voice coil 123-2 can be connected by the first connector 127; thus, a clearance channel 123-2 can be naturally formed between the short sidewalls of the two voice coils.

[0239] Accordingly, the length of the magnetic circuit assembly in the long axis direction is greater than its width in the short axis direction, and the short side of the outer magnetic circuit component 122-1 and the short side of the inner magnetic circuit component 122-2 are connected by the magnetic circuit connector 122-3, so that the magnetic circuit assembly is constructed with no connection on the long side and a connection on the short side. That is, the magnetic circuit connector 122-3 passes through the magnetic gap between the short side of the inner magnetic circuit component 122-2 and the short side of the outer magnetic circuit component 122-1.

[0240] On the one hand, while maintaining the integrated structure of the voice coil assembly, connecting the long sidewalls of the two voice coils enhances the structural stability of the voice coil assembly itself and improves the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, creating conditions for ensuring active noise cancellation. On the other hand, the structure of the magnetic circuit assembly with no long side connection and a short side connection facilitates the formation of a strong and uniform magnetic field between the long side of the inner magnetic circuit component 122-2 and the long side of the outer magnetic circuit component 122-1. This allows the magnetic field to pass through the magnetic gap as much as possible, achieving full utilization of the magnetic field and effectively enhancing the driving force of the voice coil assembly.

[0241] 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 projection of the first voice coil 123-1 coincides with the orthographic projection of the second voice coil 123-2. In this case, on a reference plane parallel to the vibration direction, there is a gap in the vibration direction between the orthographic projection of the first voice coil 123-1 and the orthographic projection of the second voice coil 123-2, thereby forming a clearance channel 123-3 between them based on the existence of the gap. In this case, after the magnetic circuit connector 122-3 passes through the clearance channel 123-3 in a direction perpendicular to the vibration direction, both ends of the magnetic circuit connector 122-3 are connected to the inner magnetic circuit component 122-2 and the outer magnetic circuit component 122-1, respectively.

[0242] As mentioned above, the first voice coil 123-1 and the second voice coil 123-2 can be connected by the first connector 127. In some embodiments, please refer to Figure 31. The first voice coil 123-1 and the second voice coil 123-2 each include a voice coil skeleton 123a and a coil 123b wound around the outer periphery of the voice coil skeleton. For ease of distinction and description, the voice coil skeleton 123a and the coil 123b of the first voice coil 123-1 are defined as the first skeleton and the first coil, respectively, and the voice coil skeleton and the coil of the second voice coil 123-2 are defined as the second skeleton and the second coil, respectively. The first skeleton and the second skeleton are respectively arranged around the inner magnetic circuit component 122-2 between the inner magnetic circuit component 122-2 and the outer magnetic circuit component 122-1, and the first connector 127 is connected between the first skeleton and the second skeleton, thereby achieving both separation of the coils of the two voice coils and forming a clearance channel 123-3 between the two voice coil skeletons 127-1.

[0243] Based on the connection relationship between the first skeleton, the second skeleton and the first connector 127, a skeleton structure of the voice coil is formed. Due to the high structural strength and strong connection stability of the skeleton structure, the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2 can be further guaranteed, and it is applicable to voice coils 123-1 and second voice coils 123-2 of different sizes.

[0244] In some embodiments, the voice coil assembly can adopt an integrated skeleton structure; specifically, referring to Figure 31, the first connector 127, the first skeleton, and the second skeleton are an integrated structure, which can effectively prevent the coil from detaching from the skeleton during the vibration of the voice coil assembly, thereby enhancing the structural stability and integrity of the voice coil assembly itself.

[0245] In some embodiments, the voice coil assembly can adopt a split-frame structure. Specifically, the first frame has an extension portion extending beyond the first coil (e.g., the extension portion of the first frame is located on the long side of the first voice coil 123-1), and the second frame has an extension portion extending beyond the second coil (e.g., the extension portion of the second frame is located on the long side of the second voice coil 123-2). The extension portions of the first frame and the second frame are fixedly connected (e.g., bonded). This allows for the connection of the first voice coil 123-1 and the second voice coil 123-2 to form a frame structure, while also accommodating the size difference between the first voice coil 123-1 and the second voice coil 123-2 to form a clearance channel 123-3. In this case, it can be understood that the voice coil assembly with a frame structure is constructed by omitting the first connector 127, or that the extension portions of the first voice coil 123-1 and the second voice coil 123-2 are connected to form the first connector 127.

[0246] In other embodiments, the first and second frames may not have extended portions. In this case, the first connector 127 may be a patch structure, which is attached and fixed to the same side of the first and second frames, thereby constructing a voice coil assembly that forms a frame structure.

[0247] In some voice coil assemblies employing a skeleton structure or a skeletonless structure, regarding the first connector 127 itself (see Figures 32A, 32B, and 33), the first connector 127 can adopt a bent structure. The bent first 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 it can be connected between the first voice coil 123-1 and the second voice coil 123-2 in the short axis direction. Since the bent structure has a smaller mass, the load on the first voice coil 123-1 and the second voice coil 123-2 can be reduced, increasing the output of the speaker 120, thereby improving the active noise cancellation effect of the headphones on larger ambient noise in open-back wearing mode. At the same time, it can also be adapted to first voice coil 123-1 and second voice coil 123-2 of different sizes.

[0248] Of course, the first connector 127 can also adopt other suitable structural forms. For example, the first connector 127 can also adopt a gasket structure, in which case the first voice coil 123-1 and the second voice coil 123-2 can be glued and fixed to the first connector 127 by clamping it; the first connector 127 can also adopt a patch structure, and the first connector 127 can also be attached and fixed to the same side of the first voice coil 123-1 and the second voice coil 123-2. All these variations will not be elaborated here.

[0249] In some embodiments, when the voice coil assembly employs a skeleton structure, the materials of the first skeleton, the second skeleton, and the first connector 127 may include aluminum alloy, or low-density PMI (Polymethacrylimide) or PC (Polycarbonate) materials, or hybrid materials (such as PC material with added glass fiber or carbon fiber). This reduces the load on the first voice coil 123-1 and the second voice coil 123-3, which is beneficial for improving the driving force coefficient of the speaker 120.

[0250] Figure 35 is a schematic diagram of the frequency response curve of the loudspeaker shown in Figure 34; wherein, taking the example that the size of the first voice coil 123-1 is smaller than the size of the second voice coil 123-2, curve L321 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 L322 represents the output sound pressure level of the larger voice coil (first voice coil 123-1) when the first voice coil 123-1 and the second voice coil 123-2 are driven simultaneously. The output sound pressure level of the second diaphragm 121-2 corresponding to the second voice coil 123-2 is shown by curve L323, which represents the output phase of the first diaphragm 121-1 corresponding to the small 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 L324 represents 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.

[0251] It should be noted that the data acquisition environment shown in Figure 35 can be as follows: a fixed speaker 120 (e.g., handheld, directly fixed via a fixed platform, fixed using a handheld device, etc.), using a 0.5Vrms voltage excitation, and measuring the frequency response and phase of the corresponding diaphragm through 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.

[0252] As shown in Figure 35, curves L321 and L322 are relatively flat in the 200Hz-10kHz range, without peaks or valleys, indicating good vibration and output consistency between the first diaphragm 121-1 and the second diaphragm 121-2. Curves L323 and L324 have a phase difference of approximately 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 vibration consistency is good. Within the 200Hz-10kHz frequency range, the phase change of either curve L323 or L324 is no greater than 20°, indicating good phase consistency between the first diaphragm 121-1 and the second diaphragm 121-2.

[0253] In summary, by using the first connector 127 to connect the first voice coil 123-1 and the second voice coil 123-2, and by correspondingly connecting the first voice coil 123-1 to the first diaphragm 121-1 and the second voice coil 123-2 to the second diaphragm 121-1, synchronous and co-directional vibration of the first diaphragm 121-1 and the second diaphragm 121-1 can be achieved, and the consistency of vibration is good.

[0254] It should be noted that, as in some of the embodiments described above, the sound pressure level of the sound output from the first sound outlet 112-1 is set to be greater than the sound pressure level of the sound output from the second sound outlet 112-2; this refers to the sound pressure level of the corresponding sound within the frequency range from the peak resonant frequency of the first resonant peak to the peak resonant frequency of the second resonant peak.

[0255] In some embodiments, referring to Figures 27 and 37, the inner magnetic circuit component 122-2 includes an inner magnet (for ease of distinction, this inner magnet is defined as the first inner magnet 122-21), a first magnetic guide plate 122-22, and a third magnetic guide plate 122-23; the outer magnetic circuit component 122-1 includes an outer magnet (for ease of distinction, this outer magnet is defined as the first outer magnet 122-11), a fourth magnetic guide plate 122-12, and a second magnetic guide plate 122-13; wherein, the first outer magnet 122-11 surrounds the outer periphery of the first inner magnet 122-21 to form a magnetic gap with the first inner magnet 122-21; for example, the first outer magnet 122-11 may be an integral annular magnet arranged around the first outer magnet 122-11; the first magnetic guide plate 122-22 is stacked facing the first diaphragm 121-1. The first inner magnet 122-21 is placed on the first inner magnet 122-21, and the third magnetic plate 122-23 is stacked on the first inner magnet 122-21 facing the second diaphragm 121-2; the fourth magnetic plate 122-12 is stacked on the first outer magnet 122-11 facing the first diaphragm 121-1, and the second magnetic plate 122-13 is stacked on the first outer magnet 122-11 facing the second diaphragm 121-2; for example, the fourth magnetic plate 122-12 and the second magnetic plate 122-13 can each be an integral annular magnetic plate stacked on both sides of the first outer magnet 122-11; and the magnetic circuit connector 122-3 is arranged with magnetic gaps and clearance channels 121-3 passing through it along the vibration direction, and one end of the magnetic circuit connector 122-3 is connected to the first magnetic plate 122-22 and the other end is connected to the second magnetic plate 122-13.

[0256] Firstly, the cooperation of the first inner magnet 122-21 and the first outer magnet 122-11 effectively increases the magnetic field strength near the voice coil assembly, making the magnetic field distribution more uniform. This enhances the driving force of the voice coil assembly, ensuring the consistency of vibration between the first diaphragm 121-1 and the second diaphragm 121-2. This, in turn, supports increasing the width of the flat region of the frequency response curve of the sound output from the first sound outlet 112-1, enabling the headphones to actively reduce ambient noise over a wider frequency range. Secondly, the stacking arrangement of the first inner magnet 122-21, the first outer magnet 122-11, and related magnetic conductors further improves the structural stability of the magnetic circuit assembly, thereby enhancing the vibration stability of the speaker 120. Furthermore, it helps reduce the manufacturing difficulty of the magnetic circuit assembly, facilitating the assembly of the speaker 120. Thirdly, the annular structure of the first outer magnet 122-11 allows the first outer magnet 122-11 to have a larger volume, thereby increasing the magnetic flux and thus enhancing the driving force of the speaker 120; and the annular structure of the first outer magnet 122-11 can also reduce assembly difficulty and improve assembly efficiency.

[0257] In some embodiments, referring to Figures 27 and 37, at least one of the first magnetic plate 122-22 and the second magnetic plate 122-13 is integrally formed with the magnetic circuit connector 122-3. This reduces the number of components in the magnetic circuit assembly, further enhances the structural stability of the magnetic circuit assembly, and reduces the manufacturing difficulty of the magnetic circuit assembly. For example, the first magnetic plate 122-22 and the magnetic circuit connector 122-3 are integrally formed. The magnetic circuit connector 122-3 is bent from the outer peripheral edge of the first magnetic plate 122-22 towards the side where the second magnetic plate 122-13 is located along the vibration direction. Correspondingly, the second magnetic plate 122-13 is provided with a fixing structure (e.g., a groove structure, a notch structure, etc.) to fix the end of the magnetic circuit connector 122-3 away from the first magnetic plate 122-22 to the second magnetic plate 122-13. This helps to reduce the processing and manufacturing difficulty of the magnetic circuit assembly and even the speaker 120.

[0258] In some embodiments, the magnetic circuit connector 122-3 and the corresponding magnetic conductive plate can also adopt a separate combination structure. For example, the side of the first magnetic conductive plate 122-22 facing the first inner magnet 122-21 is provided with a receiving groove for accommodating the magnetic circuit connector 122-3. The magnetic circuit connector 122-3 is inserted into the receiving groove in a stacked form, and the end of the magnetic circuit connector 122-3 extends out from the receiving groove to connect to the second magnetic conductive plate 122-13. Alternatively, the magnetic circuit connector 122-3 is stacked and fixed on the side of the first magnetic conductive plate 122-22 facing the first inner magnet 122-21, and the two ends of the magnetic circuit connector 122-3 in the long axis direction extend out from between the first magnetic conductive plate 122-22 and the first inner magnet 122-21 and connect to the second magnetic conductive plate 122-13.

[0259] In this way, the structural connection area between the magnetic circuit connector 122-3 and the corresponding magnetic conductive plate can be effectively increased, and the structural connection strength between the magnetic circuit connector 122-3 and the corresponding magnetic conductive plate can be enhanced, so that the magnetic circuit connector 122-3 can establish a stable structural connection relationship between the outer magnetic circuit component 122-1 and the inner magnetic circuit component 122-2.

[0260] In other embodiments, the magnetic circuit connector 122-3 may also adopt an integral structure or a split combination structure, and be connected between the third magnetic plate 122-23 and the fourth magnetic plate 122-12, which will not be described in detail here.

[0261] In some embodiments, the outer magnetic circuit component 122-1 may omit the first outer magnet 122-11. The outer magnetic circuit component 122-1 includes a magnetic ring, which is essentially a magnetic ring constructed as an integral ring based on the fourth magnetic plate 122-12 and the second magnetic plate 122-13. This magnetic ring encircles the outer periphery of the inner magnetic circuit component 122-2, thereby forming a magnetic gap between them. The magnetic circuit connector 122-3 passes through the clearance channel 121-3 and the magnetic gap along the vibration direction, connecting the first magnetic plate 122-22 and the magnetic ring. At least one of the first magnetic plate 122-22 and the magnetic ring can be integrally formed with the magnetic circuit connector 122-3, or it can be a separate assembly. This reduces the number of components in the magnetic circuit assembly and enhances its structural stability.

[0262] In some embodiments, the magnetic circuit connector 122-3 can be made of a weakly magnetic or non-magnetic material. For example, the magnetic circuit connector 122-3 can be made of spring steel, which has high stiffness and weak magnetic permeability. This avoids magnetic short circuits between the inner magnetic circuit component 122-2 and the outer magnetic circuit component 122-1, or prevents the magnetic circuit connector 122-3 from shunting the magnetic field, allowing the magnetic field to pass through the magnetic gap as much as possible, thereby increasing the driving force on the voice coil assembly. Simultaneously, while ensuring the structural strength of the magnetic circuit assembly, the thickness of the magnetic circuit connector 122-3 can be reduced (e.g., by drilling holes or reducing weight). This allows for an increase in the size of the outer magnetic circuit component 122-1 (e.g., the first outer magnet 122-11), improving the electromagnetic conversion efficiency (i.e., BL value) of the speaker 120 and ensuring optimal vibration performance.

[0263] In some embodiments, all or part of the magnetic conductive plates may be omitted in the magnetic circuit assembly; for example, when the first magnetic conductive plate 122-22, the third magnetic conductive plate 122-23, the fourth magnetic conductive plate 122-12, and the second magnetic conductive plate 122-13 are omitted, the magnetic circuit connector 122-3 is directly connected between the first outer magnet 122-11 and the first inner magnet 122-21; specifically, the magnetic circuit connector 122-3 may be made of a weakly magnetic material or a non-magnetic material (such as spring steel), and the two ends of the magnetic circuit connector 122-3 in the vibration direction are respectively connected to the first outer magnet 122-11 and the first inner magnet 122-21. For example, the third magnetic plate 122-23 and the fourth magnetic plate 122-12 are omitted, and the magnetic circuit connector 122-3 is connected to the first magnetic plate 122-22 and the second magnetic plate 122-13 at both ends in the vibration direction (for example, the magnetic circuit connector 122-3 can be an integral structure with at least one of the first magnetic plate 122-22 and the second magnetic plate 122-13); and so on, which will not be elaborated here.

[0264] Considering that the magnetic circuit assembly affects the electromagnetic conversion efficiency of the speaker 120, thereby affecting the output performance of the speaker 120 and the active noise cancellation effect of the headphones; therefore, by designing the size and relationship of the relevant components in the magnetic circuit assembly, support can be provided to improve the performance of the speaker 120 and the active noise cancellation effect of the headphones.

[0265] Please refer to Figures 36 and 41. Figure 36 is a schematic diagram of the electromagnetic conversion efficiency (i.e., BL value) of loudspeakers with different sizes of inner magnetic circuit component 122-2 and outer magnetic circuit component 122-1 according to some embodiments of this application. The data in Figure 36 are measured under the condition that the width of the magnetic gap is 1.1 mm and the width of the magnetic circuit connector 122-3 is 0.7 mm.

[0266] Referring to Figure 37, the ratio of the width Wim of the inner magnetic circuit component 122-2 to the width Wom of the outer magnetic circuit component 122-1 is defined as Wim / Wom. In Figure 36, 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.

[0267] Please refer to Figure 37. The width refers to the dimensional parameter of the relevant component in the direction perpendicular to the vibration direction. For example, the width of the outer magnetic circuit component 122-1 refers to the distance between the outer surface and the inner surface of the outer magnetic circuit component 122-1, and the width of the inner magnetic circuit component 122-2 refers to the width of the cross-section of the inner magnetic circuit component 122-2.

[0268] As shown in Figure 36, the BL value of the speaker 120 is optimal when the ratio of the width of the inner magnetic circuit component 122-2 to the width of the outer magnetic circuit component 122-1 is 7.19. Further increasing the ratio of the width of the inner magnetic circuit component 122-2 to the width of the outer magnetic circuit component 122-1 will reduce the BL value of the speaker 120.

[0269] Therefore, by designing the size ratio of the external magnetic circuit component 122-1 and the internal magnetic circuit component 122-2, the electromagnetic conversion efficiency of the loudspeaker 120 can be guaranteed and the driving force of the voice coil assembly can be improved.

[0270] 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 length of the inner magnetic circuit component 122-2 (e.g., the first inner magnet 122-21) in the long axis direction to the thickness of the sidewall of the outer magnetic circuit component 122-1 (e.g., the first outer magnet 122-11 or the magnetic ring) in the long axis direction can be between 1.7 and 33; the ratio of the width of the inner magnetic circuit component 122-2 in the short axis direction to the thickness of the sidewall of the outer magnetic circuit component 122-1 in the short axis direction is between 1.7 and 33.

[0271] Furthermore, in some embodiments, the ratio of the length of the first inner magnet 122-21 in the long axis direction to the thickness of the sidewall of the first outer magnet 122-11 in the long axis direction may not exceed 6.7, and the ratio of the width of the first inner magnet 122-21 in the short axis direction to the thickness of the sidewall of the first outer magnet 122-11 in the short axis direction may not exceed 2.7. This can significantly improve the BL value of the speaker 120, thereby enhancing the sound output performance of the speaker 120.

[0272] For example, the speaker 120 has a circular outline, and the ratio of the thickness of the inner magnetic circuit element 122-2 (e.g., the first inner magnet 122-21) in the radial direction (i.e., the direction corresponding to the major axis or the minor axis) to the thickness of the sidewall of the outer magnetic circuit element 122-1 (e.g., the first outer magnet 122-11 or the magnetic ring) in the radial direction is between 1.7 and 33.

[0273] It should be noted that the sidewall thickness of the external magnetic circuit component 122-1 refers to the distance between the outer peripheral surface and the inner peripheral surface of the external magnetic circuit component 122-1.

[0274] Figures 38A and 38B are schematic diagrams illustrating the electromagnetic conversion efficiency of loudspeakers with magnets and magnetic plates of different sizes according to some embodiments of this application. Figure 38A shows the trend of electromagnetic conversion efficiency of loudspeaker 120 when the thickness of the magnet (e.g., the first inner magnet 122-21) is constant (e.g., 2 mm) and the thickness of the magnetic plate (e.g., the first magnetic plate 122-22) is changed. Figure 38B shows the trend of electromagnetic conversion efficiency of loudspeaker 120 when the thickness of the magnetic plate (e.g., the first magnetic plate 122-22) is constant (e.g., 0.7 mm) and the thickness of the magnet (e.g., the first inner magnet 122-21) is changed.

[0275] As shown in Figure 38A, the BL value of the loudspeaker 120 increases with the increase of the magnetic plate thickness (i.e., the ratio of the magnet thickness to the magnetic guide thickness, h_magnet / h_lead, decreases). However, when the magnetic plate thickness increases to a certain value, the BL value reaches its maximum value. Excessively increasing the magnetic plate thickness will cause the magnetic field lines to disperse and not be effectively concentrated near the voice coil, thus reducing the magnetic field near the voice coil. When the magnetic plate thickness decreases (i.e., the ratio of the magnet thickness to the magnetic guide thickness increases), the magnetic saturation of the magnetic plate will decrease, reducing the magnetic permeability and thus reducing the magnetic field strength passing through the voice coil. The BL value reaches its maximum value when the ratio of the magnet thickness to the magnetic guide thickness is 1.4, but when the ratio of the magnet thickness to the magnetic guide thickness is between 1 and 4, the BL value is relatively large.

[0276] As shown in Figure 38B, the BL value of the loudspeaker 120 increases with the increase of the magnet thickness (i.e., the ratio of the magnet thickness to the magnetic conductor thickness, h_magnet / h_lead, decreases), but the rate of increase of the BL value decreases. This may be because as the magnet thickness increases, the magnetic conductor plate becomes magnetically saturated, and further increasing the magnet thickness does not significantly increase the amount of magnetic field that can be gathered through the magnetic conductor plate and pass through the voice coil. Specifically, when the ratio of the magnet thickness to the magnetic conductor thickness is between 1 and 4, the BL value increases rapidly. When the ratio of the magnet thickness to the magnetic conductor thickness is greater than 4, the rate of increase slows down significantly, the magnetic conductor plate begins to become magnetically saturated, and the overall electromagnetic conversion efficiency of the loudspeaker 120 is reduced.

[0277] Therefore, in order to improve the electromagnetic conversion efficiency of the loudspeaker 120, in some embodiments, the ratio of the thickness of the first inner magnet 122-21 to the thickness of the first magnetic plate 122-22 (and the third magnetic plate 122-23) can be between 1 and 4, and the ratio of the thickness of the first outer magnet 122-11 to the thickness of the fourth magnetic plate 122-12 (and the second magnetic plate 122-13) can be between 1 and 4.

[0278] In some embodiments, referring to Figures 26 to 29, the magnetic circuit assembly further includes a support assembly, which may include a first support 122-4 and a second support 122-5. The first support 122-4 is connected to the outer periphery of the fourth magnetic plate 122-12, and the second support 122-5 is connected to the outer periphery of the second magnetic plate 122-13. The first support 122-4 and the fourth magnetic plate 122-12, as well as the second support 122-5 and the second magnetic plate 122-13, can be connected by injection molding, adhesive, bolts, snaps, or other means. The outer periphery of the first diaphragm 121-1 is fixed to the first support 122-4 (e.g., with adhesive), and the outer periphery of the second diaphragm 121-2 is fixed to the second support 122-5 (e.g., with adhesive).

[0279] On the one hand, by combining the first bracket 122-4, the second bracket 122-5 and the external magnetic circuit component 122-1, the basket in some existing loudspeakers or the frame 125 mentioned in the aforementioned embodiments can be replaced, which can make the first external magnet 122-11 have a larger volume size, enhance the magnetic flux, and thus enhance the driving force of the voice coil assembly; 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.

[0280] 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 plate 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.

[0281] In some embodiments, referring to Figure 29, the first bracket 122-4 has a first receiving groove surrounding the fourth magnetic plate 122-12, and the second bracket 122-5 has a second receiving groove surrounding the second magnetic plate 122-13; wherein, the outer periphery of the fourth magnetic plate 122-12 is inserted into the first receiving groove, and the outer periphery of the second magnetic plate 122-13 is inserted into the second receiving groove; exemplaryly, the first bracket 122-4 can be integrally formed on the fourth magnetic plate 122-12 by injection molding, die-cutting or other methods, and the first bracket 122-4 covers the outer periphery of the fourth magnetic plate 122-12, in which case the first receiving groove is equivalent to being naturally formed in the first bracket 122-4.

[0282] 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.

[0283] In some embodiments, referring to Figures 27 and 29, the first support 122-4, the fourth magnetic plate 122-12, and the first diaphragm 121-1 together form a first chamber 120a inside the speaker 120, and the second support 122-5, the second magnetic plate 122-13, 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 part of the common cavity 111-3, and the two are located on both sides of the magnetic circuit assembly in the vibration direction.

[0284] At this point, please refer to Figure 29. 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.

[0285] 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.

[0286] 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.

[0287] In some embodiments, referring to Figure 37, the first support 122-4 and the second support 122-5 are separately arranged in the vibration direction, thus forming an accommodating gap between them that surrounds the outer magnetic circuit component 122-1 (specifically, the first outer magnet 122-11). The circuit board 150 can be housed and fixed within this accommodating gap, for example, by attaching it to the outer peripheral surface of the first outer magnet 122-11. This effectively reduces the overall size of the speaker 120, further enhancing its structural compactness.

[0288] As described in some of the embodiments above, a limiting component 130 is provided between the first housing 110 and the speaker 120; in this case, referring to FIG29, 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 bracket 122-4 to form a space for accommodating sealant between the two, and the peripheral sidewall of the second cover 134 surrounds the outer periphery of the second bracket 122-5 to form a space for accommodating sealant between the two. By filling the space for accommodating sealant, a sealed and fixed connection between the limiting component 130 and the speaker 120 is achieved.

[0289] 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.

[0290] In some embodiments, referring to FIG29, 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 loudspeaker 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.

[0291] 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.

[0292] 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.

[0293] In some embodiments, the air pressure balance channel 120e can be sealed with a mesh, a waterproof and breathable membrane, etc., to improve the waterproof performance of the speaker 120.

[0294] In some embodiments where the first diaphragm 121-1 and the second diaphragm 121-2 are connected by a voice coil assembly, the magnetic circuit assembly and the voice coil assembly may also adopt other structural combinations to ensure the consistency of synchronous and unidirectional vibration of the two diaphragms, thereby providing support for the shift of the peak resonant frequency of the first resonant peak to the lower frequency range and the shift of the peak resonant frequency of the second resonant peak to the higher frequency range.

[0295] Referring to Figure 39A, the magnetic circuit assembly may include a magnetic shield 1221 and a second inner magnet 1222. The second inner magnet 1222 may be disposed within the voice coil 123. The magnetic shield 1221 and the second inner magnet 1222 are spaced apart in a direction perpendicular to the vibration direction. The sidewall of the magnetic shield 1221 may be a folded structure with an opening facing the bottom of the magnetic shield 1221. The folded structure includes an inner sidewall 12211 and an outer sidewall 12212 of the magnetic shield 1221. A first magnetic gap is formed between the inner sidewall 12211 and the second inner magnet 1222, and at least a portion of the first voice coil 123-1 is located within the first magnetic gap. A second magnetic gap is formed between the inner sidewall 12211 and the outer sidewall 12212 of the magnetic shield 1221, and at least a portion of the second voice coil 123-2 is located within the second magnetic gap. Meanwhile, the first voice coil 123-1 is connected to the first diaphragm 121-1 to drive the first diaphragm 121-1 to vibrate and produce sound; the second voice coil 123-2 is connected to the second diaphragm 121-2 to drive the second diaphragm 121-2 to vibrate and produce sound.

[0296] In this way, by using different voice coils to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate respectively, the first diaphragm 121-1 and the second diaphragm 121-2 can vibrate synchronously and generate sound. For example, the sounds generated and output by the two diaphragms can be superimposed to enhance the output performance of the headphones and improve the effect of active noise cancellation for larger ambient noises. Furthermore, by adjusting the resonant frequency of the headphones, the distortion of the headphone output can be reduced, so that the headphones have a flatter output over a wider frequency range, thereby enhancing the active noise cancellation effect.

[0297] In some embodiments, referring to Figure 39B, a second outer magnet 1223 is disposed on the outer wall 12212 of the magnetic shield 1221. The magnetization direction of the second outer magnet 1223 may be the same as or opposite to the magnetization direction of the second inner magnet 1222. For example, the N pole of the second inner magnet 1222 may be located at the upper end, and the N pole of the second outer magnet 1223 may be located at the upper end (as shown in Figure 39B). Alternatively, the N pole of the second inner magnet 1222 may be located at the upper end, and the N pole of the second outer magnet 1223 may be located at the lower end (as shown in Figure 39G).

[0298] Because the second voice coil 123-2 is relatively far from the second inner magnet 1222, the magnetic field strength near the second voice coil 123-2 is relatively weak, which may result in insufficient driving force for the second voice coil 123-2. Therefore, by setting the second outer magnet 1223, the magnetic field strength near the second voice coil 123-2 can be increased, thereby improving the driving force of the second voice coil 123-2. This helps to improve the output of the speaker 120 and the active noise cancellation effect of the headphones against larger ambient noise.

[0299] In some embodiments, when the magnetization directions of the second inner magnet 1222 and the second outer magnet 1223 are the same (e.g., the N poles are both located at the upper end as shown in Figure 39B), the inner sidewall 12211 of the magnetic shield 1221 is subjected to the combined action of the second inner magnet 1222 and the second outer magnet 1223, and the inner sidewall 12211 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, thus affecting the driving force of the first voice coil 123-1 and the second voice coil 123-2.

[0300] Therefore, to avoid the magnetic circuit assembly becoming too large, the size of the second inner magnet 1222 can be reduced while keeping the size of the magnetic circuit assembly unchanged (i.e., the width of the magnetic shield 1222 unchanged), thereby increasing the size of the inner wall 12211. This helps to minimize magnetic field saturation in the inner wall 12211, thereby increasing the magnetic field strength at the locations of the first voice coil 123-1 and the second voice coil 123-2, and ultimately increasing the driving force of the speaker 120. For example, referring to Figures 39B and 39C, the ratio of the thickness of the inner wall 12211 to the width of the magnetic shield 1222 can be 0.05-0.16. Furthermore, to further increase the driving force of the speaker 120, the ratio of the thickness of the inner wall 12211 to the width of the magnetic shield 1222 can be 0.06-0.15.

[0301] Furthermore, while keeping the dimensions of the magnetic circuit assembly constant (i.e., the width of the magnetic shield 1222 constant), the thickness of the inner wall 12211 can be negatively correlated with the radius of the second inner magnet 1222. For example, when the width of the magnetic shield 1222 is 16mm (at which point the radius of the magnetic shield 1222 is 8mm), the thickness of the inner wall 12211 can be 0.8mm-2.5mm; specifically, when the radius of the second inner magnet 1222 is greater than 2.35mm, the thickness of the inner wall 12211 can be 2mm-2.5mm; when the radius of the second inner magnet 1222 is greater than 2.85mm, the thickness of the inner wall 12211 can be 1.5mm-2.5mm; and when the radius of the second inner magnet 1222 is greater than 3.35mm, the thickness of the inner wall 12211 can be 1. The thickness of the inner wall 12211 can be 1.1mm-2.5mm when the radius of the second inner magnet 1222 is greater than 3.85mm; when the radius of the second inner magnet 1222 is greater than 4.35mm, the thickness of the inner wall 12211 can be 1mm-2mm; when the radius of the second inner magnet 1222 is greater than 4.85mm, the thickness of the inner wall 12211 can be 0.8mm-1.6mm; when the radius of the second inner magnet 1222 is greater than 5.35mm, the thickness of the inner wall 12211 can be 0.8mm-1.3mm.

[0302] In some embodiments, as shown in Figure 39D, the second outer magnet 1223 is disposed on the inner sidewall 12211 to prevent magnetic field saturation on the inner sidewall 12211, 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. In this case, the magnetization direction of the second outer magnet 1223 can be the same as or opposite to the magnetization direction of the second inner magnet 1222.

[0303] In some embodiments, referring to Figure 39E, 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 increasing the driving force of the speaker 120, a second external magnet 1223 is provided on both the inner wall 12211 and the outer wall 12212 of the magnetic shield 1221. For ease of distinction and description, the second external magnet 1223 provided on the inner wall 12211 is defined as the third external magnet 1223-1, and the second external magnet 1223 provided on the outer wall 12212 is defined as the fourth external magnet 1223-2. In this case, the magnetization directions of the second inner magnet 1222, the third external magnet 1223-1, and the fourth external magnet 1223-2 can be the same or opposite.

[0304] For example, the magnetization directions of the second inner magnet 1222 and the third outer magnet 1223-1 can be the same, and the magnetization directions of the second inner magnet 1222 and the fourth outer magnet 1223-2 can be the same; or, the magnetization directions of the second inner magnet 1222 and the third outer magnet 1223-1 can be the same, and the magnetization directions of the second inner magnet 1222 and the fourth outer magnet 1223-2 can be opposite; or, the magnetization directions of the second inner magnet 1222 and the third outer magnet 1223-1 can be opposite, and the magnetization directions of the second inner magnet 1222 and the fourth outer magnet 1223-2 can be the same; or, the magnetization directions of the second inner magnet 1222 and the third outer magnet 1223-1 can be opposite, and the magnetization directions of the second inner magnet 1222 and the fourth outer magnet 1223-2 can be opposite.

[0305] In some embodiments, referring to Figure 39F, when a second outer magnet 1223 is disposed on the outer wall 12212 of the magnetic shield 1221, and the magnetization directions of the second inner magnet 1222 and the second outer magnet 1223 are opposite (for example, the N pole of the second inner magnet 1222 can be located at the upper end, and the N pole of the second outer magnet 1223 can be located at the lower end), the inner wall 12211 of the magnetic shield 1221 exhibits a magnetic field zero pole, and the inner wall 12211 is not responsible for magnetic conduction. In this case, the inner wall 12211 of the magnetic shield 1221 mainly serves a connecting and supporting function.

[0306] In some embodiments, as shown in FIG39G, the thickness of the inner sidewall 12211 of the magnetic shield 1221 can be designed to be smaller, or the inner sidewall 12211 can be perforated or hollowed out; for example, the size of the inner sidewall 12211 of the magnetic shield 1221 can be designed to be 0, that is, the inner sidewall 12211 structure is eliminated. This can reduce the mass and size of the speaker 120.

[0307] In some embodiments, since the second outer magnet 1223 and the second 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 12211 to connect the outer sidewall 12212 to the bottom of the magnetic shield 1221. Therefore, the outer sidewall 12212 of the long side of the magnetic shield 1221 can be connected to the bottom of the magnetic shield 1221 through the inner sidewall 12211, and the short side of the magnetic shield 1221 may not have an inner sidewall 12211.

[0308] In some embodiments, by designing the dimensions of the second inner magnet 1222 and the second outer magnet 1223, the magnetic field strength near the first voice coil 123-1 and the second voice coil 123-2 is made similar, ensuring that the driving forces of the first voice coil 123-1 and the second voice coil 123-2 are close or the same. This improves the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, thereby supporting the improvement of the output effect of the speaker 120 and the active noise cancellation effect of the headphones in the case of large ambient noise in the open-back wearing mode. For example, the volume ratio of the second outer magnet 1223 to the volume of the second inner magnet 1222 can be 0.3-3.

[0309] When the volume of the second outer magnet 1223 is too small relative to the volume of the second inner magnet 1222, the driving force of the second voice coil 123-2, which is closer to the second outer magnet 1223 and farther from the second inner magnet 1222, is smaller, while the driving force of the first voice coil 123-1, which is farther from the second outer magnet 1223 and closer to the second 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 second outer magnet 1223 is too large relative to the volume of the second inner magnet 1222, the driving force of the second voice coil 123-2, which is closer to the second outer magnet 1223 and farther from the second inner magnet 1222, is larger, while the driving force of the first voice coil 123-1, which is farther from the second outer magnet 1223 and closer to the second 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.

[0310] In other words, when the volume difference between the second outer magnet 1223 and the second 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. Therefore, 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 ratio of the volume of the second outer magnet 1223 to the volume of the second inner magnet 1222 can be 0.5-1.5.

[0311] The following mainly describes the structure of the speaker 120 when the first diaphragm 121-1 and the second diaphragm 121-2 are directly fixedly connected to achieve synchronous and co-directional vibration of the two diaphragms. It can be understood that the direct connection between the first diaphragm 121-1 and the second diaphragm 121-2 can ensure the consistency of the vibration of the two diaphragms, thereby providing support for the shift of the peak resonant frequency of the first resonant peak to the lower frequency range and the shift of the peak resonant frequency of the second resonant peak to the higher frequency range, thus ensuring that the headphones can achieve active noise cancellation in a wider frequency range.

[0312] Please refer to Figures 40 to 42. The first diaphragm 121-1 and the second diaphragm 121-2 are directly connected by the second connector 126 so that the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously and in the same direction. For example, the magnetic circuit assembly may be provided with a through hole that passes through the second inner magnet 1222, the magnetic guide plate at the upper end of the second inner magnet 1222, and the bottom of the magnetic guide cover 1221 at the lower end of the second 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. The through-hole design allows the gas in the common cavity 111-3 between the first diaphragm 121-1 and the second diaphragm 121-2 to 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. This minimizes the compression of the common cavity 111-3 by the two diaphragms and avoids affecting the peaks and valleys of the resonance peaks of the frequency response curve, thereby improving the output quality of the headphones and thus enhancing the active noise cancellation effect of the headphones.

[0313] In some embodiments where the magnetic circuit assembly is formed by combining an outer magnetic circuit component and an inner magnetic circuit component, the through hole can pass through the first magnetic guide plate, the inner magnet, and the second magnetic guide plate, so that the second connector 126 can pass through the inner magnetic circuit component and connect between the first diaphragm 121-1 and the second diaphragm 121-2; this will not be elaborated here.

[0314] 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. For example, the Young's modulus of the material of the second connector 126 can be 100MPa-150MPa. 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, for example, 120MPa.

[0315] In some embodiments, considering the need to improve the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, the contact areas between the two ends of the second connector 126 and the first diaphragm 121-1 and the second diaphragm 121-2 should not be too small, so as to better transmit deformation and power between the first diaphragm 121-1 and the second diaphragm 121-2. However, if the size of the second connector 126 is too large, it will result in an excessively large through-hole size in the magnetic circuit assembly, affecting the driving force coefficient of the speaker 120 and thus affecting the output of the speaker 120.

[0316] Therefore, in order 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 dimensions of the second connector 126 can be 3.4mm*1.4mm*4.7mm.

[0317] In some embodiments, to avoid the second connector 126 placing excessive load on the first diaphragm 121-1 and the second diaphragm 121-2, and to ensure the driving force coefficient of the speaker 120, 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. Therefore, 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 between 100 kg / m³ and 140 kg / m³. Furthermore, to further reduce the load on the first diaphragm 121-1 and the second diaphragm 121-2, the density of the second connector 126 can be between 105 kg / m³ and 120 kg / m³, for example, 110 kg / m³.

[0318] Figure 43 is a schematic diagram of the driving force coefficient of the loudspeaker 120 corresponding to different sizes of through holes according to some embodiments of this application; wherein, taking the second connector 126 as a prism of 3.4mm*1.4mm*4.7mm as an example, the driving force coefficient of the loudspeaker 120 shown in Figure 43 is measured when the through hole size is 0mm*0mm, 2mm*1mm, 4mm*2mm, 5mm*2.5mm, 6mm*3mm, and 10mm*5mm respectively.

[0319] Where the through hole size is 0mm*0mm, it means that no through hole is made. In this case, it can be regarded that the first diaphragm 121-1 and the second diaphragm 121-2 are not directly connected through the second connector 126, but the first voice coil 123-1 and the second voice coil 123-2 are connected, thereby indirectly connecting the first diaphragm 121-1 and the second diaphragm 121-2 (as shown in Figure 44).

[0320] As shown in Figure 43, the larger the size of the through hole, 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, which is a small decrease; when the through hole size is 6mm*3mm, the driving force coefficient of the speaker 120 decreases by 0.15.

[0321] Since the second connector 126 is provided through a through hole, the size of the through hole will also affect 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, the connection strength of the second connector 126 may be insufficient, and the second connector 126 may be prone to breakage and damage.

[0322] Taking all factors into consideration, in some embodiments, in order to enable the speaker 120 to have a large driving force coefficient, the second connector 126 has a suitable size, the length of the through hole can be 2mm-10mm, and the width can be 1mm-5mm.

[0323] 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 first connector 127. The first 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.

[0324] Thus, by directly connecting the first diaphragm 121-1 to the second diaphragm 121-2 and 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. Simultaneously, the direct connection between the first diaphragm 121-1 and the second diaphragm 121-2 via the second connector 126 also reduces the difficulty of achieving precise alignment when connecting the first voice coil 123-1 and the second voice coil 123-2, thereby reducing operational complexity.

[0325] In other embodiments, referring to Figure 44, when the magnetic circuit assembly has a through hole, the first diaphragm 121-1 and the second diaphragm 121-2 may not be directly connected through the second connector 126. Instead, the first voice coil 123-1 and the second voice coil 123-2 are connected through the first connector 127, so that the first diaphragm 121-1 and the second diaphragm 121-2 are indirectly connected. In this case, the through hole 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, resulting in frequency response peaks and valleys, improving the output quality of the headphones, and enhancing the active noise cancellation effect of the headphones.

[0326] As in some of the aforementioned embodiments, the second outer magnet 1223 is disposed on the magnetic shield 1221. In this case, when the long side portion and the short side portion of the second outer magnet 1223 are separate structures, in order to fix the second outer magnet 1223 and prevent it from falling off, the magnetic circuit assembly may include a frame 125. The frame 125 is disposed around the second outer magnet 1223, and the frame 125 cooperates with the magnetic shield 1221 to fix the second outer magnet 1223.

[0327] As in some of the aforementioned embodiments, the magnetic circuit assembly may include a magnetic shield 1221, a second inner magnet 1222, a second 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.

[0328] For example, referring to Figures 45A to 45C, the second outer magnet 1223 can be a ring structure, surrounding the magnetic shield 1221. The ring structure of the second outer magnet 1223 allows it to have a larger volume, thereby increasing the magnetic flux and thus enhancing the driving force of the speaker 120. Furthermore, the ring structure of the second outer magnet 1223 also reduces assembly difficulty and improves assembly efficiency.

[0329] In some embodiments where the second outer magnet 1223 has a ring structure and is disposed on the magnetic shield 1221, the magnetic circuit assembly may not have a frame 125, but the second outer magnet 1223 may be installed and fixed by the upper fixing frame 128-1 and the lower fixing frame 128-2.

[0330] Specifically, referring to Figures 45A to 45C, the first diaphragm 121-1 can be fixed to the upper fixing frame 128-1, and the upper side of the second outer magnet 1223 is connected to the upper fixing frame 128-1 through the upper outer magnetic guide plate 128-3; the second diaphragm 121-2 can be fixed to the lower fixing frame 128-2, and the lower side of the second outer magnet 1223 is connected to the lower fixing frame 128-2 through the lower outer magnetic guide plate 128-4. At this time, the lower side of the second inner magnet 1222 is connected to the bottom of the magnetic guide cover 1221, and the upper side of the second inner magnet 1222 is connected to the inner magnetic guide plate 128-5. 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 to have a larger design size, which will further increase the volume of the magnets (such as the second inner magnet 1222, the second outer magnet 1223, etc.) to further increase the driving force of the speaker 120.

[0331] In some embodiments, the upper fixing frame 128-1 and the lower fixing frame 128-2 can be made of plastic; and the upper fixing frame 128-1 and the lower fixing frame 128-2 can be connected to the corresponding magnetic plate by injection molding, adhesive, bolts, clips, etc. Of course, the upper fixing frame 128-1 and the lower fixing frame 128-2 can also be made of metal, and the upper fixing frame 128-1 and the lower fixing frame 128-2 can be connected to the corresponding magnetic plate by adhesive, welding, bolts, clips, etc.

[0332] In some embodiments, the outer magnetic plate corresponding to the second outer magnet 1223 (e.g., upper outer magnetic plate 128-3, lower outer magnetic plate 128-4, etc.) may include two interconnected components, one of which is used to connect with the corresponding fixing frame, and the other is used to connect with the second outer magnet 1223. The two components may be separately connected or integrally formed.

[0333] In some embodiments, referring to Figure 46A, the magnetic circuit assembly 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. The magnetic circuit fixing ring 129 connects the fixing frame, the corresponding outer magnetic plate, and the second outer magnet 1223 into a whole, further improving the installation stability of the magnetic circuit assembly, thereby enhancing the vibration stability of the speaker 120. The magnetic circuit fixing ring 129 and the corresponding fixing frame can be separately connected or integrally formed.

[0334] In some embodiments, please refer to Figure 46B, the magnetic circuit assembly may not have an upper fixing frame 128-1 and a lower fixing frame 128-2. Instead, a magnetic circuit fixing ring 129 can be used to replace the upper fixing frame 128-1 and the lower fixing frame 128-2, and the magnetic circuit assembly can be directly assembled and fixed by the magnetic circuit fixing ring 129, thereby reducing the assembly difficulty.

[0335] 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 129 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.

[0336] In some embodiments, please refer to Figures 47A and 47B. The magnetic circuit fixing ring 129 may include two annular sub-rings. The two sub-rings are respectively disposed on the upper and lower sides of the second outer magnet 1223 to install and fix the upper and lower sides of the second outer magnet 1223 and the corresponding outer magnetic plate, fixing frame, etc.

[0337] In some embodiments, please refer to Figures 48A and 48B. The magnetic circuit fixing ring 129 may include two semi-circular sub-rings. The interval between the two sub-rings may be set in the direction of the short side of the speaker 120. In this case, the sub-rings may be installed and fixed on the long side of the outer magnetic plate, the corresponding long side of the second outer magnet 1223, and the corresponding long side of the fixing frame.

[0338] In other embodiments, the spacing between the two sub-rings can also be set in the direction of the long side of the speaker 120; in this case, the sub-rings can be installed and fixed on 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 second outer magnet 1223, and the corresponding short side and part of the corresponding long side of the mounting bracket.

[0339] As mentioned earlier, diaphragm design can also support active noise cancellation for headphones over a wide frequency range. For dual-diaphragm speakers, the structures of the two diaphragms need to be designed in a coordinated manner to ensure that the peak resonant frequency of the first resonant peak of the speaker 120 is low, while avoiding unnecessary distortion during resonance, thereby avoiding affecting the active noise cancellation effect of the headphones and achieving active noise cancellation support over a wide frequency range. Therefore, the following mainly introduces the diaphragm and its related structures.

[0340] In some embodiments, referring to FIG28, the loudspeaker 120 includes a first diaphragm 121-1, a second diaphragm 121-2, a support assembly, a voice coil assembly, and a magnetic circuit assembly, etc.; the first diaphragm 121-1 and the second diaphragm 121-2 are spaced apart and opposite each other in the vibration direction; the support assembly, the voice coil assembly, and the magnetic circuit assembly are disposed between the first diaphragm 121-1 and the second diaphragm 121-2, 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 (for the sound-emitting part 100, this radial direction may include the major axis direction and the minor axis direction). The first diaphragm 121-1 and the second diaphragm 121-2 have the same structure and are symmetrically arranged along a reference plane perpendicular to the vibration direction. This arrangement ensures the consistency of the co-directional vibration of the first diaphragm 121-1 and the second diaphragm 121-2, thereby improving the stability of the loudspeaker 120 output.

[0341] In some embodiments, by designing the diaphragm (e.g., the first diaphragm 121-1, the second diaphragm 121-2) to adjust the first resonant peak of the speaker 120 at low frequencies (e.g., below 200Hz), the low-frequency output of the speaker 120 is improved, thereby enhancing the active noise cancellation effect of the headphones on low-frequency environmental noise.

[0342] Figure 63 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 (polyurethane) diaphragm of 0.35 mm thickness; curve L402 represents the frequency response of the headphones with a PU diaphragm of 0.45 mm thickness; and curve L403 represents the frequency response of the headphones with a PU diaphragm of 0.55 mm thickness. As shown in Figure 63, the low-frequency resonant peak of curve L401 is around 145 Hz, that of curve L402 is around 185 Hz, and that of curve L403 is around 230 Hz. Comparing curves L401, L402, and L403, the resonant frequencies corresponding to the low-frequency resonant peaks gradually decrease as the diaphragm thickness decreases. Therefore, in some embodiments, to enable the speaker 120 to have a flatter output over a wider frequency range and to improve the low-frequency output of the speaker 120, thereby enhancing the active noise cancellation effect of the headphones on low-frequency ambient noise, the low-frequency resonant frequency of the speaker 120 can be between 100Hz and 300Hz, and the diaphragm material can include PU material, with a diaphragm thickness of 0.2mm-0.07mm. In some embodiments, to further reduce the low-frequency resonant frequency of the speaker 120, when the diaphragm material is PU, the diaphragm thickness can be 0.35mm-0.55mm.

[0343] Furthermore, in some embodiments, 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 thereby improve the active noise cancellation effect of the headphones on low-frequency environmental noise, the diaphragm material may include liquid silicone, and the diaphragm thickness may be 0.055mm-0.1mm.

[0344] In some embodiments, for a dual-diaphragm loudspeaker, in order 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. Referring to Figure 49, taking the first diaphragm 121-1 as an example, the first diaphragm 121-1 includes a diaphragm 1211, a center mount 1212, and a fixing ring 1213. The diaphragm 1211 is connected around the outer periphery of the center mount 1212, and the center mount 1212 is connected to the voice coil assembly (for example, 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 diaphragm 1211 radially away from the center mount 1212 is connected to the fixing ring 1213, and the support assembly is fixedly connected to the fixing ring 1213 (for example, the fixing ring 1213 of the first diaphragm 121-1 is bonded or welded to the first support 122-4).

[0345] It should be noted that the first diaphragm 121-1 and the second diaphragm 121-2, which are assembled from the diaphragm 1211, the center patch 1212, and the fixing ring 1213, can be understood as component structures. That is, the first diaphragm 121-1 can be called the first diaphragm assembly, and the second diaphragm 121-2 can be called the second diaphragm assembly. Taking the first diaphragm assembly as an example, 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 diaphragm 1211 on the first diaphragm 121-1 or the diaphragm 1211 itself can be regarded as the folded ring area of ​​the first diaphragm 121-1.

[0346] In some embodiments, the diaphragm 1211 may be made of silicone material. In some embodiments, the inlay 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).

[0347] This design, using silicone material with high temperature stability as the surround area of ​​the diaphragm 1211 or 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 the strong adhesive and high mechanical strength center patch 1212 to establish a structural connection between the voice coil assembly and the diaphragm 1211, and the use of the fixing ring 1213 to establish a structural connection between the support assembly and the diaphragm 1211, effectively enhances the structural stability between the diaphragm assembly and the voice coil assembly, overcoming the poor adhesive performance of silicone material. This ensures smooth vibration of the diaphragm assembly and voice coil assembly to produce sound while preventing the voice coil assembly and diaphragm assembly from detaching during vibration.

[0348] Due to the poor adhesive properties of silicone material, it is difficult to use glue to bond and fix the diaphragm 1211 to the center patch 1212 and the fixing ring 1213. In some embodiments, the diaphragm assembly (i.e., the first diaphragm 121-1 and the second diaphragm 121-2) can be a one-piece structure. For example, the diaphragm 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.

[0349] Referring to Figures 50 and 51, in some embodiments, the diaphragm 1211 may include a first connecting portion 1211-1, a folded ring portion 1211-2, and a second connecting portion 1211-3; wherein, 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.

[0350] Furthermore, in some embodiments, the diaphragm 1211 further includes a third connecting portion 1211-4 and a fourth connecting portion 1211-5; wherein, one end of the third connecting portion 1211-4 in the vibration direction is connected to the connection between the folded ring portion 1211-2 and the first connecting portion 1211-1, which can also be understood as the folded ring portion 1211-2 extending a certain length along the vibration direction toward one side of the magnetic circuit assembly to form the third connecting portion 1211-4; one end of the fourth connecting portion 1211-5 in the vibration direction is connected to the connection between the folded ring portion 1211-2 and the second connecting portion 1211-3, which can also be understood as the folded ring portion 1211-2 extending a certain length along the vibration direction toward one side of the magnetic circuit assembly to form the fourth connecting portion 1211-5.

[0351] 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 is attached to the inner circumferential surface of the fixing ring 1213.

[0352] 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 diaphragm 1211 in the radial direction, and the outer peripheral surface refers to the surface farther from the center point of the diaphragm 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.

[0353] With this configuration, based on the first surface P1 and the third surface P3, the diaphragm 1211 covers the outer surface and outer peripheral side of the mating center 1212. This can effectively increase the connection area between the diaphragm 1211 and the mating center 1212, enhance the connection strength between the diaphragm 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.

[0354] 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 can 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 can also 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.

[0355] In some embodiments, when the outer surface and outer peripheral side of the middle patch 1212 are covered and bonded by the diaphragm 1211, the lower surface of the middle patch 1212 can also be covered and bonded by the diaphragm 1211 to further enhance the stability of the connection between the diaphragm 1211 and the middle patch 1212.

[0356] Specifically, the diaphragm 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 diaphragm 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.

[0357] In some embodiments, referring to FIG50, 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 is bent and arched relative to the first connecting portion 1211-1 in the vibration direction, away from the voice coil assembly. 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 and the like inside the loudspeaker 120, allowing the magnetic circuit assembly to have a larger design size, which is beneficial to enhance the driving force of the magnetic circuit assembly and the voice coil assembly on the diaphragm assembly, but also avoids interference between the diaphragm 1211 and the sound-generating structure such as the magnetic circuit assembly due to deformation during vibration, thus ensuring the quality of sound output.

[0358] Figure 52 shows the BLx curve of the product of magnetic flux density (B) and voice coil length (L) of loudspeaker 120 as a function of the voice coil assembly movement distance (x). Referring to Figure 52, when the voice coil assembly moves to ±0.6 mm, the BLx curve changes by approximately 17%, and when the voice coil assembly moves to ±0.8 mm, the BLx curve changes by approximately 25%. Considering that the KMs curve of the diaphragm assembly is one of the key parameters affecting the distortion of loudspeaker 120, if the proportion of change in the corresponding KMs curve is within a similar range within the range of voice coil assembly movement distance, the BLx curve of loudspeaker 120 will have a better match with the KMs curve of the diaphragm assembly, which is beneficial to giving 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 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.

[0359] In some embodiments, referring to FIG51, 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.

[0360] Specifically, as the second width Lm changes, different first widths Lac will cause significant changes in the shape of the KMs curve of the diaphragm assembly, thereby affecting the distortion of the final speaker 120. Figure 53 shows the KMs curves for different first ratios LL. Referring to Figure 53, 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. 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 relatively small. 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 relatively small.

[0361] Therefore, setting the first ratio LL of the diaphragm 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.

[0362] 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.

[0363] In some embodiments, referring to Figure 54, 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 the KMs curve; therefore, the second ratio TL can be no greater than 0.12.

[0364] Specifically, Figure 55 shows the KMs curves for different second ratios TL. Referring to Figure 55, 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, keeping the second ratio TL of the diaphragm 1211 no higher than 0.12 allows the KMs curve to match the BLx curve, which is beneficial for giving the loudspeaker 120 lower distortion. For example, the second ratio TL can be set to 0.1, 0.06, or other values ​​less than 0.12.

[0365] In some embodiments, referring to Figure 56, 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 1211-2 and the height difference between the inner and outer ends of the folded ring 1211-2 in the radial direction will affect the KMs curve, and thus affect the distortion of the loudspeaker 120, the third ratio HLO can be no greater than 0.232.

[0366] Specifically, Figure 57 shows the KMs curves for different third ratios HLO. Referring to Figure 39C, 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 moves to ±0.6 mm 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 diaphragm 1211 to no greater than 0.232 allows the KMs curve to match the BLx curve, thereby obtaining a loudspeaker 120 with lower distortion.

[0367] In some embodiments, referring to Figure 58, 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, the fourth ratio HTO can be no greater than 0.36.

[0368] Specifically, Figure 59 shows the KMs curves for different fourth ratios HTO. Referring to Figure 59, 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 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 diaphragm 1211 to no greater than 0.36, the KMs curve can be matched with the BLx curve, thereby obtaining a loudspeaker 120 with lower distortion.

[0369] 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.

[0370] In some embodiments, referring to Figure 60, 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 a 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.

[0371] Specifically, Figure 61 shows the KMs curves for different fifth ratios TT. Referring to Figure 61, as the fifth ratio TT changes from 1.2 to 0.8, the corresponding KMs curve gradually flattens. For example, when the voice coil assembly moves to ±0.6mm 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 diaphragm 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.

[0372] 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.

[0373] In some embodiments, referring to Figure 49, 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. It can also be understood that the connecting region 1212-2 surrounds and connects to the outer periphery of the central region 1212-1, and the edge region 1212-3 surrounds and connects to the outer periphery of the connecting region 1212-2; wherein, the connecting region 1212-2 is in the vibration direction The center patch 1212 is inclined relative to the edge region 1212-3 and the center region 1212-1, so that there is a height difference in the vibration direction between the geometric center of the center region 1212-1 and the plane containing the edge region 1212-3, thereby constructing a dome-shaped structure. The edge region 1212-3 is connected to the diaphragm 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.

[0374] 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.

[0375] Because the arched center mount 1212 has high strength and height, it is beneficial 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. At the same time, the arched center mount 1212 can also prevent the diaphragm 1211 from shaking during large-amplitude vibrations, thus ensuring that the voice coil assembly and the magnetic circuit assembly will not collide. In addition, the edge area 1212-3 can provide ample connection area for the voice coil assembly and the diaphragm 1211, ensuring that the voice coil assembly and the diaphragm 1211 can be stably connected to the center mount 1212.

[0376] 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.

[0377] The above examples illustrate this application only to aid understanding and are not intended to limit its scope. Those skilled in the art to which this application pertains can make various simple deductions, modifications, or substitutions based on the ideas presented.

Claims

1. An open earphone, characterized by, The earphone comprises a sound generating part and an ear hook configured to place the sound generating part near the ear but not to block the ear canal in a wearing state; wherein the sound generating part comprises a first shell and a loudspeaker arranged inside the first shell, a shell wall of the first shell facing the outer ear canal side in the wearing state is an inner side wall, the inner side wall is provided with a first sound outlet hole in acoustic communication with the loudspeaker, a frequency response curve of sound output to the outside of the first shell through the first sound outlet 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.

2. Open headphones according to claim 1, characterized in that 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 13.

3. The open ear headphone of claim 1, wherein 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 20.

4. The open ear headphone of claim 1, wherein The peak resonance frequency of the first resonance peak is not greater than 300 Hz.

5. The open ear headphone of claim 4, wherein The peak resonance frequency of the second resonance peak is not less than 3.65 kHz.

6. The open headphone of claim 1, wherein The shell wall opposite to the inner side wall and away from the outer ear canal side of the first shell in the wearing state is an outer side wall, and the outer side wall is provided with a second sound outlet hole in acoustic communication with the loudspeaker.

7. The open ear headphone of claim 6, wherein In a frequency band 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 through the first sound outlet hole is greater than the sound pressure level of the sound output through the second sound outlet hole.

8. The open ear headphone of claim 6, wherein, A first acoustic cavity in communication with the first sound outlet hole is formed between the loudspeaker and the inner side wall, and a second acoustic cavity in communication with the second sound outlet hole is formed between the loudspeaker and the outer side wall.

9. The open headphone of claim 8, wherein, The loudspeaker comprises first and second diaphragms that vibrate synchronously in the same direction; the first diaphragm is spaced opposite to the inner side wall to form the first acoustic cavity, and the sound generated by the first diaphragm in the first acoustic cavity is output through the first sound outlet hole; the second diaphragm is spaced opposite to the outer side wall to form the second acoustic cavity, and the sound generated by the second diaphragm in the second acoustic cavity is output through the second sound outlet hole.

10. The open ear headphone of claim 9, wherein, The loudspeaker further comprises a magnetic circuit assembly and a voice coil assembly, the magnetic circuit assembly is arranged between the first and second diaphragms, and the voice coil assembly is arranged through the magnetic gap of the magnetic circuit assembly; The voice coil assembly comprises first and second voice coils arranged in the vibration direction of the first and second diaphragms and connected by a connecting piece, one end of the first voice coil away from the second voice coil is connected to the first diaphragm, and one end of the second voice coil away from the second voice coil is connected to the second diaphragm; the magnetic circuit assembly cooperates with the voice coil assembly to drive the first and second diaphragms to vibrate synchronously in the same direction.

11. The open ear headphone of claim 9, wherein The loudspeaker further comprises a support assembly and a voice coil assembly, the support assembly is arranged between the first diaphragm and the second diaphragm around the voice coil assembly; wherein the first diaphragm and the second diaphragm each comprise a diaphragm, a center piece and a fixed ring, the diaphragm is connected between the center piece and the fixed ring around the center piece, the center piece is connected with the voice coil assembly, and the fixed ring is connected with the support assembly; the diaphragm is made of silica gel material, and the center piece is made of one of magnesium-aluminum alloy, carbon fiber, surface aluminum-coated polymethyl methacrylimide and surface aluminum-coated polyethylene naphthalate.

12. The open ear headphone of claim 11, wherein The diaphragm comprises a first connecting portion, a folded ring portion connected around the outer periphery of the first connecting portion, and a second connecting portion connected around the outer periphery of the folded ring portion; wherein the first connecting portion is connected with the center piece, and the second connecting portion is connected with the fixed ring; in the vibration direction of the first diaphragm and the second diaphragm, the folded ring portion is curved and arched relative to the first connecting portion towards the side away from the voice coil assembly; 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 a diameter direction perpendicular to the vibration direction, 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.

13. The open ear headphone of claim 12, wherein The surface of the first connecting portion for connecting the center piece is defined as a first surface, and the surface of the second connecting portion for connecting the fixed ring is defined as a second surface; in the vibration direction, the distance from the first surface to the plane where the second surface is located is a first height, and the height from the vertex of the folded ring portion to the plane where the second surface is located is a second height, and the ratio of the first height to the second height is not greater than 0.

36.

14. The open ear headphone of claim 6, wherein, The sound generating part further comprises a limiting assembly, the limiting assembly is arranged between the loudspeaker and the first shell; the limiting assembly allows the loudspeaker to be arranged opposite to the inner side wall with a spacing, and the limiting assembly also allows the loudspeaker to be arranged opposite to the outer side wall with a spacing.

15. The open earphone of claim 14, wherein The limiting assembly is connected with the loudspeaker; in the arrangement direction of the inner side wall and the outer side wall, one end of the limiting assembly close to the inner side wall elastically abuts against the inner side wall, and one end of the limiting assembly close to the outer side wall elastically abuts against the outer side wall.

16. Open earphone according to any of claims 1-15, characterized in that The inner side wall and the loudspeaker form a first acoustic cavity communicating with the first sound hole, and the inner side wall is also provided with a sound adjusting hole communicating with the first acoustic cavity.

17. The open earphone of claim 16, 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.

18. The open ear headphone of claim 17, wherein The first sound hole and / or the sound adjusting hole are 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.

19. The open earphone of claim 16, 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%.

20. The open earphone of claim 16, wherein The sound production part has a long axis direction, a short axis direction and a thickness direction perpendicular to each other, the first acoustic cavity is formed between the loudspeaker and the inner side wall in the thickness direction; in a reference plane perpendicular to the thickness direction, the length of the projection of the first acoustic cavity in the long axis direction is not less than the width in the short axis direction; wherein the projection of the first acoustic cavity is divided into a first region and a second region arranged along the long axis direction, the sound adjusting hole is projected in the first region on the reference plane, and the first sound outlet is projected in the second region on the reference plane.

21. The open earphone of claim 20, 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%.

Images