Acoustic output device

Abstract

One or more embodiments of the present specification relate to an acoustic output device, comprising: a sound generating unit comprising: an acoustic driver; the shell is provided with a first cavity and a second cavity which are acoustically coupled with the acoustic driver, the first cavity is provided with a first sound outlet hole, the second cavity is provided with a second sound outlet hole, and the acoustic driver radiates sound outwards through the first sound outlet hole and the second sound outlet hole respectively; wherein sound transmitted between the first sound outlet hole and the second sound outlet hole has a first phase shift, an acoustic structure is arranged in the first cavity or the second cavity, and the acoustic structure enables the sound passing through to generate a second phase shift at a target frequency; the difference value range of the first phase deviation and the second phase deviation is-30 degrees to 30 degrees.

Description

Technical Field

[0001] The present invention relates to the field of acoustics, and in particular to an acoustic output device. Background Art

[0002] One of the requirements of open audio equipment is a non-omnidirectional radiated sound field. While ensuring that the near-field radiation of sound energy remains almost unchanged, the directionality of far-field radiation is selected. When conventional audio devices emit low-frequency sounds, they often exhibit monopole radiation. Although the radiation efficiency is high, under certain circumstances, the sound energy is not focused enough and there is a large amount of sound leakage in the far field. Traditional audio devices form a dipole-like structure by opening holes in the front and rear cavities, and use the dipole-like radiation mechanism to control the direction of sound radiation. This method can ensure a certain radiation efficiency, but the dipole-like control will still lead to a decrease in radiation efficiency, that is, a decrease in device sensitivity. Summary of the invention

[0003] One of the embodiments of the present specification provides an acoustic output device, comprising: a sound-emitting part, the sound-emitting part comprising: an acoustic driver; a shell, the shell having a first cavity and a second cavity acoustically coupled to the acoustic driver, a first sound outlet hole being provided in the first cavity, a second sound outlet hole being provided in the second cavity, and the acoustic driver radiating sound outward through the first sound outlet hole and the second sound outlet hole respectively; wherein, there is a first phase shift in the sound transmitted between the first sound outlet hole and the second sound outlet hole, an acoustic structure is provided in the first cavity or the second cavity, and the acoustic structure causes the passing sound to produce a second phase shift at a target frequency; and the difference between the first phase shift and the second phase shift ranges from -30° to 30°.

[0004] The embodiment of the present specification also provides an acoustic output device, including: a sound-emitting part, the sound-emitting part including: an acoustic driver; a shell, the shell having a first cavity and a second cavity acoustically coupled to the acoustic driver, a first sound outlet hole being provided in the first cavity, a second sound outlet hole being provided in the second cavity, and the acoustic driver radiating sound outward through the first sound outlet hole and the second sound outlet hole respectively; wherein, there is a first phase shift in the sound transmitted between the first sound outlet hole and the second sound outlet hole, an acoustic structure is provided in the first cavity or the second cavity, and the acoustic structure causes the passing sound to produce a second phase shift at a target frequency; and the sum of the first phase shift and the second phase shift is within the range of 150° to 210°. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0006] Figure 1 is a schematic diagram of an exemplary directional radiation sound field of an acoustic output device according to some embodiments of this specification;

[0007] Figure 2 is an example diagram of an exemplary cardioid directional radiation sound field of an acoustic output device according to some embodiments of this specification;

[0008] Figure 3 is an exemplary dual sound source radiation schematic diagram according to some embodiments of this specification;

[0009] Figure 4A-4C are the directional sound field radiation patterns of the dipoles corresponding to the values ​​of kl shown in some embodiments of this specification;

[0010] Figure 5A is an exemplary structural diagram of a sound-producing part according to some embodiments of this specification;

[0011] Figure 5B is another exemplary structural diagram of a sound-producing part according to some embodiments of the present specification;

[0012] Figure 6 is an exemplary structural diagram of an acoustic structure according to some embodiments of this specification;

[0013] Fig. 7A is an exemplary structural diagram of an acoustic structure according to some embodiments of this specification;

[0014] Figure 7B is a graph showing the relationship between the number of film layers and phase retardation according to some embodiments of the present specification;

[0015] Figure 8A-8C is an exemplary structural diagram of a sound-producing part according to some embodiments of this specification;

[0016] Fig. 9 is an exemplary structural diagram of a sound-producing part according to some embodiments of this specification;

[0017] Fig.10 is an exemplary structural diagram of a sound-producing part according to some embodiments of this specification;

[0018] Fig.11 is an exemplary structural diagram of a sound-producing part according to some embodiments of this specification;

[0019] Figure 12-13is a schematic diagram of the radiated sound field of the acoustic output device corresponding to the range of α-β shown in some embodiments of this specification;

[0020] Fig.14 It is a schematic diagram of the radiated sound field of the acoustic output device corresponding to when α=β=90° according to some embodiments of this specification. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0022] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0023] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0024] Figure 1 is a schematic diagram of an exemplary directional radiation sound field of an acoustic output device according to some embodiments of the present specification.

[0025] The acoustic output device outputs sound near the listener's ear, so that the listener can hear the sound while also radiating the sound to the surrounding environment, which causes a large degree of sound leakage from the acoustic output device. In order to reduce the sound leakage of the acoustic output device and allow more sound to be transmitted to the listener's ear canal, in some embodiments, the acoustic output device can use two sound sources with equal amplitude and opposite phase (such as Figure 1 The first sound source and the second sound source shown in FIG. 1 ) form a dipole, which can be formed as shown in FIG. Figure 1The directional radiation sound field similar to the shape of "8" shown in the figure. The directional radiation sound field similar to the shape of "8" may include two directions with extremely strong radiation. It can also be understood that the directional radiation sound field similar to the shape of "8" has two main lobes. In order to improve the listening effect of the listener, the positions of the two sound sources can be adjusted so that one main lobe points to the ear canal opening of the listener, so that the sound transmitted by the acoustic output device to the ear canal opening of the listener is loud enough. At the same time, Figure 1 It can also be seen from the schematic diagram of the directional radiation sound field of the dipole in that when one main lobe points to the ear canal opening of the listener, the other main lobe usually points to the front or side of the listener. This means that when other people are in front of or to the side of the listener, they can also clearly hear the sound leakage of the acoustic output device.

[0026] In order to reduce the sound leakage of the acoustic output device and enable more sound to be transmitted to the ear canal opening of the listener, the directionality of the radiated sound field of the acoustic output device can be enhanced by adjusting the number and / or structure of the acoustic output device. For example, the number of acoustic output devices can be multiple, and the radiated sound fields of multiple acoustic output devices are superimposed, and the total radiated sound field after superposition can have stronger directionality. For another example, the number of acoustic output devices is single, and the structure of the sound-emitting part of the acoustic output device can be designed (for example, a partition is provided outside the box of the sound-emitting part, an acoustic structure is provided in the cavity and / or the sound outlet, etc.) to change the phase difference of the two sounds generated by the sound-emitting part, so that the radiated sound field of the sound-emitting part has stronger directionality.

[0027] Figure 2 is an example diagram of an exemplary cardioid directional radiation sound field of an acoustic output device according to some embodiments of this specification. In some embodiments, the cardioid directional radiation sound field of the acoustic output device can be obtained by superimposing the radiation sound field of a dipole speaker and the radiation sound field of a monopole speaker. Figure 2 As shown in (a) in the figure, the radiated sound field of the dipole speaker can be a directional radiated sound field similar to the shape of an "8", and the radiated sound field of the monopole speaker is a directional radiated sound field that is approximately circular. Among them, "+1" and "-1" represent sound waves with equal amplitudes and opposite phases. The directional radiated sound field similar to the shape of an "8" and the directional radiated sound field that is approximately circular are superimposed to obtain Figure 2 The approximately cardioid directional radiation sound field shown in (b) has a sound pressure that is twice the sound pressure of a single directional radiation sound field (the "8"-shaped directional radiation sound field of a dipole speaker, or the approximately circular directional radiation sound field of a monopole speaker).

[0028] By superimposing the radiation sound field of the dipole speaker with the radiation sound field of the monopole speaker, a cardioid directional radiation sound field can be obtained. The cardioid directional radiation sound field has only one main lobe. The sound field radiation of the main lobe and its vicinity is extremely strong, and the sound field radiation in other directions is relatively weak (the sound field intensity in the opposite direction of the main lobe is also relatively weak). When the user wears the acoustic output device, the main lobe can be directed to the listener's ear canal opening. At this time, only the radiation directed to the ear canal opening and its vicinity is strong, while other directions are weakly directional directions, thereby reducing the sound leakage of the acoustic output device.

[0029] In order to further improve the radiation efficiency of the acoustic output device and reduce the complexity of the acoustic output device system, a single acoustic output device can be used to realize a cardioid directional radiation sound field. The principle is as follows:

[0030] Figure 3 FIG. 1 is a schematic diagram of exemplary dual sound source radiation according to some embodiments of this specification. Figure 3 As shown, the first sound source AS 1 and the second sound source AS 2 can represent two sound sources formed by the sound-generating part of the acoustic output device, P is a point in the far field, and l represents the first sound source AS 1 and the second sound source AS 2 The spacing, r 1 Indicates the first sound source AS 1 The distance to point P, r 2 Indicates the second sound source AS 2 The distance to point P, r represents the first sound source AS 1 and the second sound source AS 2 The distance from the midpoint O to point P, θ represents the first sound source AS 1 and the second sound source AS 2 AS 1 -AS 2 The angle made by the line OP connecting the midpoint O and point P.

[0031] Each of the two sound sources formed by the sound-generating part of the acoustic output device can be regarded as a monopole. The sound pressure of the monopole is expressed by the pulsating spherical sound pressure equation as follows: in, represents the sound pressure amplitude, and k represents the wave vector.

[0032] The two sound sources formed by the sound-generating part of the acoustic output device can be regarded as dipoles composed of two pulsating balls with a distance of l and opposite phases. At this time, the sound pressure can be expressed as:

[0033] When r>>l, the difference in amplitude between the sound waves radiated by the two sound sources when they reach point P is very small, and the amplitude part in equation (2) (i.e., and ) 1 and r 2 can be replaced by r, and the phase part (i.e., and The difference cannot be ignored, the distance r 1 、r 2 It can be expressed as:

[0034] When kl<1 (the frequency is not very high, for example, when the frequency is not greater than 10 kHz), substitute equation (3) into equation (2) to obtain the sound pressure of the dipole:

[0035] At this time, the directivity function of the acoustic output device is:

[0036] When kl ≥ 1 (the frequency is not very low or l cannot be ignored, for example, the frequency is greater than 100 Hz or l is greater than 5 mm), substitute equation (3) into equation (2) to obtain the sound pressure of the dipole:

[0037] At this time, the directivity function of the acoustic output device is:

[0038] Combining equations (4) to (7), it can be seen that the directivity of the dual sound source is related to the value of kl. Figure 4A-4C is the directional sound field radiation diagram of the dipole corresponding to the value of kl shown in some embodiments of this specification. Figure 4A When kl = 1, the dual-source directional sound field is similar to the shape of "8". Figure 4B When kl = 5, the dual-source directional sound field is similar to a butterfly shape. Figure 4C , when kl = 10, the side lobes of the dual-source directional sound field further increase. It can be seen that when the distance between the dual sound sources cannot be ignored, the directivity of the sound field will change with the change of frequency. Therefore, the structure and parameters of the acoustic output device can be set for different frequencies, so that the acoustic output device can achieve strong directivity sound field radiation in different scenarios with target frequencies, such as cardioid sound field radiation. For a detailed description of the structural design of the acoustic output device, see Figure 5A-Figure 11 , and its related description.

[0039] In some embodiments, the acoustic output device may include a support structure and a sound-emitting portion. The support structure may be used to carry the sound-emitting portion. In some embodiments, when the user wears the acoustic output device, the support structure may be mounted on the user's head or upper torso. In some embodiments, the support structure may include an arc structure (also called an ear hook structure) that matches the user's auricle. As an exemplary illustration only, the arc structure may include but is not limited to a hook shape, a C shape, etc. When the user wears the acoustic output device, the support structure may be mounted or clamped on the user's auricle, thereby enabling the wearing of the acoustic output device. In some embodiments, the support structure may also include a hook-shaped structure that matches the user's head or upper torso. When the user wears the acoustic output device, the hook-shaped structure may be hung on the user's auricle through the user's head or neck to enable the wearing of the acoustic output device.

[0040] The sound-emitting part can be used to generate and radiate sound outward. In some embodiments, the acoustic output device can fix the sound-emitting part near the user's ear through a supporting structure but not blocking the user's ear canal, so that the user's ear can remain open. When the user's ear remains open, the user can hear the sound output by the sound-emitting part and obtain the sound of the external environment at the same time.

[0041] Figure 5A is an exemplary structural diagram of the sound-producing part according to some embodiments of this specification. Figure 5A The sound-emitting part 500 may include an acoustic driver 510 and a shell 501, wherein the shell 501 has a first cavity 520 and a second cavity 530 acoustically coupled to the acoustic driver 510, respectively. In some embodiments, a first sound outlet 540 may be provided in the first cavity 520, and the acoustic driver 510 may radiate sound (also called the first sound) from the first sound outlet 540 through the first cavity 520; a second sound outlet 550 may be provided in the second cavity 530, and the acoustic driver 510 may radiate sound (also called the second sound) from the second sound outlet 550 through the second cavity 530. The first sound outlet 540 and the second sound outlet 550 here may be regarded as two sound sources formed by the sound-emitting part described above.

[0042] The acoustic driver 510 may be a device that can convert an electrical signal into a sound signal and output it. Exemplarily, the acoustic driver 510 may have a diaphragm and a coil and a magnetic circuit assembly that can drive the diaphragm to vibrate. In some embodiments, the number of acoustic drivers 510 may be one. At this time, the acoustic driver 510 may have a front side and a rear side, and radiate sound to the first cavity 520 and the second cavity 530 from the front side and the rear side, respectively. For example, the front side of the acoustic driver 510 may be the side of the diaphragm away from the magnetic circuit assembly, and the rear side of the acoustic driver 510 may be the side of the diaphragm facing the magnetic circuit assembly or the side of the magnetic circuit assembly away from the diaphragm. When vibrating, the side of the diaphragm away from the magnetic circuit assembly and the side facing the magnetic circuit assembly will produce sounds with the same amplitude and opposite phases. In some embodiments, the first cavity 520 and the second cavity 530 are respectively located on both sides of the diaphragm, and the diaphragm can radiate sound to the first cavity 520 and the second cavity 530 respectively when vibrating. The sound radiated by the diaphragm to the first cavity 520 can be transmitted to the first sound outlet hole according to the first sound transmission path, and radiated outward from the first sound outlet hole (the sound radiated from the first sound outlet hole is the first sound); the sound radiated by the diaphragm to the second cavity 530 can be transmitted to the second sound outlet hole according to the second sound transmission path, and radiated outward from the second sound outlet hole (the sound radiated from the second sound outlet hole is the second sound).

[0043] The shell 501 may be a regular or irregular three-dimensional structure having a cavity (i.e., a hollow portion) inside. In some embodiments, the shell 501 may be a hollow frame structure. The hollow frame structure may include, but is not limited to, regular shapes such as a rectangular frame, a circular frame, and any irregular shapes. In some embodiments, the shell 501 may be made of metal (e.g., stainless steel, copper, etc.), plastic (e.g., polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and acrylonitrile-butadiene-styrene copolymer (ABS), etc.), composite materials (e.g., metal-based composite materials or non-metal-based composite materials), etc. In some embodiments, the acoustic driver 510 may be located in the cavity formed by the shell 501, and the acoustic driver 510 is connected to the side wall of the shell 501 and separates the cavity into a first cavity 520 and a second cavity 530.

[0044] The first cavity 520 and the second cavity 530 can be cavities acoustically coupled with the acoustic driver 510. The first cavity 520 and the second cavity 530 can be used to transmit the sound generated by the acoustic driver 510. The first sound in the first cavity 520 can be radiated outward through the first sound outlet, and the second sound in the second cavity 530 can be radiated outward through the second sound outlet. The natural phase difference between the first sound and the second sound emitted from the front and back sides of the acoustic drive device is 180° (the natural phase difference can be understood as the phase difference caused only by the first sound and the second sound export position setting on the acoustic driver 510 when there is no other structural interference in the sound propagation path between the cavity and the sound outlet). In some embodiments, the number of the first sound outlet and / or the second sound outlet can be one or more. The number of sound outlets can be reasonably set according to actual needs, and this specification does not specifically limit this.

[0045] The sound radiated from the first sound outlet 540, i.e., the first sound, will also be transmitted from the outside of the sound-emitting portion 500 (for example, along the outer surface of the sound-emitting portion 500) to the second sound outlet 550, and will be superimposed with the second sound radiated from the second sound outlet 550, and the superimposed sound will be the total sound at the second sound outlet 550. In other words, the total sound at the second sound outlet 550 is the superposition of the second sound and the sound (recorded as the third sound) transmitted to the second sound outlet 550. Similarly, the sound radiated from the second sound outlet 550, i.e., the second sound, will also be transmitted from the outside of the sound-emitting portion 500 to the first sound outlet 540, and will be superimposed with the first sound radiated from the first sound outlet 540, and the superimposed sound will be the total sound at the first sound outlet 540. In other words, the total sound at the first sound outlet 540 is the superposition of the first sound and the sound (recorded as the fourth sound) transmitted to the first sound outlet 540.

[0046] During the transmission of the first sound from the outside of the sound-emitting part 500 to the second sound-emitting hole 550, since there is a first sound path difference (the sound path difference of the sound transmitted outside the sound-emitting part 500) between the first sound-emitting hole 540 and the second sound-emitting hole 550, the first sound path difference will change the phase of the first sound transmitted to the second sound-emitting hole 550, that is, the third sound obtained by the first sound transmitted to the second sound-emitting hole 550 is different from the phase of the first sound, for example, a first phase shift of angle β is generated; similarly, during the transmission of the second sound from the outside of the sound-emitting part 500 to the first sound-emitting hole 540, the first sound path difference between the first sound-emitting hole 540 and the second sound-emitting hole 550 will also change the phase of the second sound transmitted to the first sound-emitting hole 540. That is, the fourth sound obtained by the second sound transmitted to the first sound-emitting hole 540 is different from the phase of the second sound, and a first phase shift of angle β is also generated. Therefore, the phase difference between the total sound at the first sound outlet and the total sound at the second sound outlet cannot be maintained at 180° or near 180°, which affects the sound leakage reduction effect of the acoustic device in the far field.

[0047] In some embodiments, an acoustic structure is provided on the inner wall or outer side wall of the cavity of the sound-emitting part 500 to change the phase of the sound from one sound outlet to another sound outlet. For example, an acoustic structure is provided in the inner wall of the cavity of the sound-emitting part 500 to change the acoustic path of the sound propagating in the cavity, so that the sound radiated by the acoustic driver 510 has a second acoustic path difference in the process of being transmitted to the sound outlet (for example, the acoustic path difference of the second sound in the process of being transmitted from the acoustic driver 510 to the second sound outlet inside the sound-emitting part 500). The second acoustic path difference can cause a certain phase shift, i.e., a second phase shift, of the sound radiated from the sound outlet of the sound-emitting part 500, such as a shift of an angle α. That is, an acoustic structure can be provided in the first cavity 520 and / or the second cavity 530, and the first sound outlet 540 and / or the second sound outlet 550, and the acoustic structure can be used to adjust the phase of the first sound and the second sound radiated from the first sound outlet and / or the second sound outlet to cause a phase shift. In some embodiments, an acoustic structure is provided on the outer wall of the sound-emitting portion 500 to regulate the sound path between the two acoustic holes, thereby regulating the phase of the third sound obtained by transmitting the first sound from the first sound outlet hole 540 to the second sound outlet hole 550 (and / or regulating the fourth sound obtained by transmitting the second sound from the second sound outlet hole 550 to the first sound outlet hole 540), causing a phase shift (i.e., regulating the first phase shift β).

[0048] For ease of understanding, taking the acoustic structure set in the second cavity 530 as an example, it can be assumed that the phase of the first sound radiated from the first sound outlet 540 is 0°. Due to the influence of the acoustic structure in the second cavity 530, the phase of the second sound radiated from the second sound outlet 550 is deflected, and the phase after deflection is 180°+α. According to the above description, the phase of the third sound obtained by the first sound being transmitted to the second sound outlet 550 is 0°+β. At this time, at the second sound outlet 550, the phase difference between the third sound and the second sound is 180°+α-β. Similarly, the phase of the fourth sound obtained by the second sound being transmitted to the first sound outlet 540 is 180°+α+β. At this time, at the first sound outlet, the phase difference between the fourth sound and the first sound is 180°+α+β.

[0049] In some embodiments, the second phase shift α and the first phase shift β can be adjusted to adjust the sound at the first sound outlet 540 and / or the sound at the second sound outlet 550, so as to achieve the directivity of the sound. For the purpose of illustration, of the two sound outlets, the first sound outlet 540 can be closer to the listener's ear canal than the second sound outlet 550, and the line connecting the second sound outlet 550 and the first sound outlet 540 points to the direction of the listener's ear canal. At this time, in order to enhance the volume heard by the listener, the second phase shift α and the first phase shift β can be adjusted to adjust the value of 180°+α+β, so that the first sound and the fourth sound at the first sound outlet 540 are superimposed and enhanced (for example, so that 180°+α+β is close to 360°). Alternatively, in order to reduce the sound leakage of the acoustic output device, the second phase offset α and the first phase offset β can be adjusted to adjust the value of 180°+α-β, so that the second sound and the third sound at the sound outlet hole away from the ear canal opening, that is, the second sound outlet hole 550, are superimposed and canceled (for example, 180°+α-β is close to 180°). Alternatively, in order to take into account both the effect of enhancing the volume heard by the listener and reducing the sound leakage (for example, forming a strong directional sound field described elsewhere in this specification), the values ​​of 180°+α+β and 180°+α-β can be adjusted at the same time to change the sound at the first sound outlet hole 540 and the sound at the second sound outlet hole 550.

[0050] In some embodiments, the first phase shift β is caused by the transmission of sound outside the sound-emitting portion 500 due to the first sound path difference between the first sound outlet hole 540 and the second sound outlet hole 550. The transmission of sound between the two sound outlet holes outside the sound-emitting portion 500 can be approximately considered that the sound is transmitted along the outer surface of the sound-emitting portion 500, that is, the outer surface of the shell 501 (the shortest transmission path). In some embodiments, one or more partitions can be set on the outer surface of the shell 501. The partitions can change the sound path of sound transmission. By adjusting the size of the partitions, the first sound path difference can be adjusted, thereby achieving the adjustment of the first phase shift β.

[0051] Figure 5B is another exemplary structural diagram of the sound-producing part according to some embodiments of this specification. Figure 5B As shown, one or more partitions 560 may be provided on the outer surface of the shell 501. One end of the partition 560 is connected to the outer surface of the shell 501, and the other end of the partition 560 is a free end and extends in a direction away from the shell 501. The partition 560 may have a certain height. The height of the partition 560 refers to the dimension of the partition 560 along the normal direction of the outer surface of the shell 501. In some embodiments, the partition 560 may be a retractable or detachable structure. For example, the partition 560 may be a retractable plate, and the retractable plate may be retracted along the normal direction of the outer surface of the shell 501, so as to adjust the height of the retractable plate. For another example, the partition 560 may be a detachable plate-like structure, and the plate-like structure is detachably connected to the outer surface of the shell 501 by a physical connection method. As an example, the physical connection method includes but is not limited to a threaded connection, a snap connection, a hinge connection, etc. In some embodiments, the partition 560 may also be a ring-like structure. In some embodiments, when sound is transmitted along the outer surface of the shell 501, the sound needs to bypass the partition 560 when it encounters the partition 560. Therefore, the height of the partition 560 can be adjusted to adjust the first sound path difference, thereby achieving the adjustment of the first phase shift β.

[0052] Specifically, the first phase shift β caused by the first sound path difference between the first sound outlet hole 540 and the second sound outlet hole 550 is: Among them, λ is the sound wavelength, f is the sound frequency, and l' is the acoustic path between the two sound outlets.

[0053] As an example, when the partition 560 is not provided, l'=1.2 cm, and when the sound frequency f is approximately equal to 3573 Hz, a first phase shift is generated. That is, β=90°. After adding the partition 560, the acoustic path between the two sound outlets is greater than 1.2 cm. At this time, the frequency range corresponding to the same first phase offset β is less than 3573 Hz. In other words, by setting a partition or changing the height of the partition, the required first phase offset β can be generated at a specific frequency (i.e., the target frequency). Similarly, at the target frequency, by adjusting the height of the partition 560, different first phase offsets β corresponding to the target frequency can be obtained. The target frequency may refer to a specific frequency that needs to be regulated in different scenarios. For example, in a call scenario, the target frequency may be 2000Hz, 2500Hz, 3000Hz, etc. For another example, in a heavy metal music scenario, the target frequency may be 8000Hz, 8500Hz, 9000Hz, etc. In some embodiments, the target frequency may be in the range of 500Hz to 3000Hz. In some embodiments, the target frequency may be in the range of 2000Hz to 3000Hz. In some embodiments, the target frequency may be in the range of 8000Hz to 9000Hz.

[0054] In some embodiments, the height of the partition 560 can be 0-2 cm, and the corresponding first sound path difference can be 1.2 cm-5.2 cm. When the first phase offset β=90°, the corresponding frequency range is about 824 Hz-3573 Hz. As an example, when the acoustic output device is worn on the user's ear, the auricle can be used as the partition 560. At this time, the height of the partition 560 is about 1.6 cm, and the corresponding first sound path difference is 4.4 cm. When β=90°, the corresponding frequency is about 974 Hz. In some embodiments, the height of the partition 560 can be 3.7 cm, and when β=90°, the corresponding frequency is about 500 Hz. In some embodiments, the height of the partition 560 can be 0.47 cm, and when β=90°, the corresponding frequency is about 2000 Hz. In some embodiments, the height of the partition 560 can be 0.11 cm, and when β=90°, the corresponding frequency is about 3000 Hz.

[0055] As an example, when the frequency band range to be regulated (i.e., the target frequency) is a frequency that the human ear is sensitive to, such as when the target frequency is 3000 Hz, by adjusting the height of the partition 560, the first phase shift β can be adjusted to 37.8°~163.8°. As an example, when the auricle is used as the partition 560, the corresponding first phase shift β is 138°. For another example, when the target frequency is 1000 Hz, by adjusting the height of the partition 560, the first phase shift β can be 12.6°~54.6°. For another example, when the target frequency is 2000 Hz, by adjusting the height of the partition 560, the first phase shift β can be 25.2°~109.2°.

[0056] The measurement method of the first phase shift β can be: place a sound source and a first probe (such as a microphone) at the first sound outlet of the acoustic output device (or a spatial position very close to the sound outlet), use the first probe to measure the first phase of the sound at the first sound outlet, place a second probe at the second sound outlet, use the second probe to measure the second phase of the sound at the second sound outlet, and calculate the phase difference between the first phase and the second phase, which can be regarded as the first phase shift β.

[0057] By setting the partition 560 as a height-adjustable structure, the height of the partition 560 can be adjusted to adjust the first phase shift β corresponding to the sound of different frequency bands, so as to meet different needs. In some embodiments, the height of the partition 560 can be adjusted according to different target frequencies in different scenarios. For example, in a call scenario, the main sound frequency band is approximately 2000Hz to 3000Hz, and the partition 560 can be set to the first height. In the scenario of listening to heavy metal music, the main frequency band of the sound is the high frequency band (such as 8000Hz to 9000Hz), and the partition 560 can be set to the second height. In the case where the low-frequency sound has a longer wavelength than the high-frequency sound, in order to obtain the same first phase shift to achieve the directivity of the sound in the corresponding frequency range, in some embodiments, the first height can be set to be greater than the second height.

[0058] In some embodiments, an acoustic structure is provided at the cavity and / or the sound outlet, and the second phase difference between the first sound and the second sound can be adjusted by using the acoustic structure. Figure 5B , an acoustic structure 570 can be set at the second sound outlet 550. The acoustic structure 570 can be used to adjust the actual output phase of the second sound to produce a second phase offset α, thereby adjusting the second phase difference between the first sound and the second sound, that is, 180°+α. In this embodiment, the acoustic structure 570 is set at the second sound outlet 550 as an example for explanation. It can be understood that in other alternative embodiments, the acoustic structure 570 can also be set in the first cavity 520 or the second cavity 530 or the first sound outlet 540, or different acoustic structures can be set in the first cavity 520 (and / or the first sound outlet 540) and the second cavity 530 (and / or the second sound outlet 550).

[0059] Figure 6 is an exemplary structural diagram of an acoustic structure according to some embodiments of this specification. Figure 6 In some embodiments, the acoustic structure 570 may include a phase tube 600 . Figure 6The arrow in indicates the direction of sound propagation. In some embodiments, the phase tube 600 may be a tubular structure, and a plurality of grids 610 are disposed on the inner wall of the tubular structure, and the plurality of grids 610 are arranged in a staggered manner. When sound propagates in the phase tube 600, it must bypass the plurality of grids 610 for transmission. Therefore, the sound path of the sound transmitted in the phase tube 600 is greater than the length of the phase tube 600. The sound path of the sound transmitted in the phase tube 600 that is longer than the length of the phase tube can affect the second sound path difference generated by the phase tube 600. The second sound path difference causes a second phase shift α between the first sound and the second sound. In some embodiments, the second sound path difference can be adjusted by setting the number and height of the grids 610, thereby adjusting the second phase shift α. The length of the phase tube 600 refers to the length of the phase tube along the arrow direction (i.e., the direction of sound propagation). The height of the grid 610 refers to the projection length of the grid in the direction perpendicular to the arrow direction. In some embodiments, in order to meet the requirements of the second sound path difference, so as to achieve the corresponding second phase shift, the number of grids 610 in the phase tube 600 can be set to be greater than or equal to 2. In some embodiments, in order to further increase the second acoustic path difference and thus achieve the corresponding second phase shift, the number of grids 610 in the phase tube 600 can be set to be greater than or equal to 3. As an example, when the second acoustic path difference generated by the phase tube 600 is one-quarter of the sound wavelength, the second phase difference shift that the phase tube 600 can provide is 90°. In some embodiments, when the acoustic output device is applied to headphones, the phase tube 600 can be set at the lower sound outlet (i.e. Figure 5B One end of the phase tube 600 along the length direction is acoustically connected to the second sound outlet hole 550 , and the other end is acoustically connected to the second cavity 530 .

[0060] Fig. 7A is an exemplary structural diagram of an acoustic structure according to some embodiments of this specification. Fig. 7A In some embodiments, the acoustic structure 570 may include a sound outlet pipe 700 . Fig. 7AThe arrow in indicates the direction of sound propagation. In some embodiments, the sound outlet tube 700 may be a tubular structure, and the inner wall of the tubular structure may be inlaid with a film 710, the film 710 has a middle-stick mass, and the film 710 regulates the sound phase through the middle-stick mass. The middle-stick mass refers to the mass corresponding to the middle stickers of different sizes in the middle of the film 710. The larger the middle-stick mass, the greater the phase delay caused by the sound outlet tube 700. In some embodiments, in order to meet the requirements of the second phase shift generated by the sound outlet tube 700, the middle-stick mass of the film 710 may be 1.9 mg to 4.9 mg. In some embodiments, in order to meet the requirements of the second phase shift generated by the sound outlet tube 700, the middle-stick mass of the film 710 may be 2.5 mg to 4 mg. In some embodiments, the number of layers of the film 710 may be single-layer, double-layer or multi-layer. The number of layers of the film 710 is positively correlated with the magnitude of the second phase shift generated by the sound outlet tube 700. That is, the more layers of the film 710, the greater the phase delay caused by the sound outlet tube 700; the fewer layers of the film 710, the smaller the phase delay caused by the sound outlet tube 700. In some embodiments, in order to meet the requirement of the second phase shift generated by the sound outlet tube 700, the number of layers of the film 710 may be no less than 2. In some embodiments, in order to meet the requirement of the second phase shift generated by the sound outlet tube 700, the number of layers of the film 710 may be no less than 3. As an example, Figure 7B is a graph showing the relationship between the number of film layers and phase retardation according to some embodiments of this specification. Figure 7B As shown, the number of film layers in the first row L1 is 0, the number of film layers in the second row L2 is 1, the number of film layers in the third row L3 is 2, the number of film layers in the fourth row L4 is 3, and the number of film layers in the fifth row L5 is 4. The gray value of each row corresponds to the magnitude of the sound pressure (-1Pa to 1Pa). Figure 7B It can be seen that each row has two troughs and three peaks. Taking the first row L1 as an example, the three peaks correspond to different peak frequencies, such as the first peak frequency f1, the second peak frequency f2 and the third peak frequency f3. Comparing the first row L1 and the second row L2, it can be seen that compared with the acoustic output device in which a sound outlet tube without a film is placed, when a sound outlet tube with a layer of film is placed in the acoustic output device, the second peak frequency f2 and the third peak frequency f3 of the acoustic output device move to the left, and a phase delay occurs. Compared with the third row, the fourth row and the fifth row, it can be seen that the more the number of film layers, the more the peak resonance frequency of the acoustic output device moves to the left, and the greater the phase delay. In some embodiments, the sound outlet tube 700 can be set at the second sound outlet hole 550, and the number of layers of the film 710 can be set to adjust the phase of the sound at the second sound outlet hole 550, thereby realizing the regulation of the second phase offset α between the first sound and the second sound.

[0061] Figure 8A-8C It is an exemplary structural diagram of the sound-producing part shown in some embodiments of this specification. Figure 8A-8C The sound generating part 800 shown in FIG. Figure 5A The sound-emitting part 500 shown is substantially the same, except that the acoustic structure is different. In some embodiments, the acoustic structure 810 can be disposed in the cavity, and the acoustic structure 810 can be used to adjust the actual output phase of the first sound and / or the second sound, thereby adjusting the second phase offset α between the first sound and the second sound. In some embodiments, the acoustic structure 810 can make a first sound path propagated in the first cavity 520 and a second sound path propagated in the second cavity 530 have a second sound path difference, thereby changing the second phase offset α between the first sound radiated from the first sound outlet 540 and the second sound radiated from the second sound outlet 550. In this embodiment, the acoustic structure 810 is disposed in the second cavity 530 as an example for explanation. It can be understood that in other alternative embodiments, the acoustic structure 810 can also be disposed in the first cavity 520, or different acoustic structures are disposed in the first cavity 520 and the second cavity 530. In some embodiments, the acoustic structure 810 may include a baffle, one end of the baffle is connected to the inner wall of the second cavity 530, and the other end of the baffle is a free end. In some embodiments, Fig. 8A As shown, four baffles can be set in the second cavity 530, of which two baffles are set on the first inner wall 5301 of the second cavity 530, and the remaining two baffles are set on the second inner wall 5302 (the second inner wall 5302 is set opposite to the first inner wall 5301), and the free ends of the baffles on the two inner walls are respectively set opposite to each other. At this time, there is a gap between the free ends of the two oppositely set baffles, and the sound can bypass the baffle and be transmitted from the gap to the second sound outlet 550. In some embodiments, the number and / or position of the baffles in the second cavity 530 can also be set in other ways. For example, Figure 8B As shown, a baffle can be provided on only one inner wall of the second cavity 530 (for example, the second inner wall 5302), one end of the baffle is connected to the second inner wall 5302, and the free end of the baffle extends to the vicinity of the first inner wall 5301 (a gap is formed between the free end of the baffle and the first inner wall 5301), and the sound can bypass the baffle and be transmitted to the second sound outlet 550 from the gap between the free end of the baffle and the first inner wall 5301. For another example, Figure 8C As shown, the two ends of the baffle can be connected to the first inner wall 5301 and the second inner wall 5302 respectively. In this case, a hole can be opened on the baffle, and the sound can bypass the baffle and be transmitted to the second sound outlet 550 through the hole. In the process of sound bypassing the baffle and transmitting to the second sound outlet 550, the distance traveled by the sound (that is, the sound path) is changed compared to when no baffle is set. The sound waves radiated from the front side of the acoustic driver 510 are radiated from the first sound outlet 540 to the outside through the first cavity 520. The distance traveled by the sound wave is the first sound path L. 1The sound waves radiated from the rear side of the acoustic driver 510 are radiated to the outside from the second sound outlet 550 through the second cavity 530 and the acoustic structure 810. The distance traveled by the sound waves is the second sound path L 2 , the first sound path L 1 With the second interval L 2 There is a second sound path difference between them.

[0062] The phase delay between the first sound radiated from the first sound outlet 540 and the second sound radiated from the second sound outlet 550 may be: Where c represents the speed of sound. Therefore, the second phase offset α between the first sound and the second sound is: α=-2πf·Δt. (10)

[0063] It can be seen that by controlling the first sound path L 1 and the second interval L 2 The actual output second phase shift α of the first sound and the second sound is controlled by the second sound path difference between the first sound and the second sound.

[0064] It is understandable that the number, position, size and arrangement of the baffles may affect the second sound path L of the sound wave in the second cavity 530. 2 , thereby affecting the second phase shift α between the first sound and the second sound. Therefore, the number, position, size and setting method of the baffles can be reasonably set according to the requirements of the second phase difference between the first sound and the second sound.

[0065] In addition, it can be seen in this embodiment that when other parameters (e.g., the first sound path and the second sound path) are the same, the second phase shift between the first sound and the second sound is negatively correlated with the frequency. The higher the frequency, the smaller the second phase shift between the first sound and the second sound; the lower the frequency, the larger the second phase shift between the first sound and the second sound.

[0066] Fig. 9 It is an exemplary structural diagram of the sound-producing part shown in some embodiments of this specification. Fig. 9 The sound generating part 900 shown in FIG. Figure 5AThe structures of the sound - generating parts 500 shown are generally the same, with the difference lying in the different acoustic structures. An acoustic structure for changing the sound propagation speed can be provided in the first cavity 520 and / or the second cavity 530 of the sound - generating part 900. For example, the acoustic structure can be a slow - speed acoustic structure that can slow down the speed of sound when it propagates through itself. The speed of sound waves propagating in air is faster than the speed of sound waves propagating in the slow - speed acoustic structure. In some embodiments, the slow - speed acoustic structure can include at least one of acoustic mesh, acoustic porous material, etc. When sound waves pass through the micropores in the mesh or porous material, due to the viscous effect of the micropores on air, the speed of sound waves slows down when passing through the micropores, thus achieving the effect of slow speed. Specifically, the speed of sound waves propagating in air (also called the normal speed of sound) is c, and the speed of sound waves propagating in the slow - speed acoustic structure (also called the equivalent speed of sound) is c'. From the above description, it can be seen that c' < c. Therefore, by setting a slow - speed acoustic structure in the cavity to change the sound propagation speed, the actual output phase of the first sound and / or the second sound can be regulated, thereby adjusting the second phase shift α between the first sound and the second sound.

[0067] In this embodiment, the case where the slow - speed acoustic structure 910 is provided in the second cavity 530 is taken as an example for illustration. As Fig. 9 shown, a slow - speed acoustic structure 910 can be provided in the second cavity 530. The sound waves radiated from the front side of the acoustic driver 510 radiate to the outside from the first sound outlet hole 540, and the path traveled by this sound wave is the first sound path L 1 , and the sound waves radiated from the rear side of the acoustic driver 510 radiate to the outside from the second sound outlet hole 550. The path traveled by this sound wave can include the second sound path L 2 traveled through air and the third sound path L 3 .

[0068] The differential time delay between the first sound radiated from the first sound outlet hole 540 and the second sound radiated from the second sound outlet hole 550 can be: where c represents the normal speed of sound, and c' represents the equivalent speed of sound in the slow - speed acoustic structure 910. Then, the second phase shift α between the first sound and the second sound is: α = - 2πf·Δt. (12)

[0069] It can be seen from this that the actual output second phase shift α between the first sound and the second sound can be controlled by controlling the equivalent speed of sound and / or the third sound path L 3 traveled by sound waves in the slow - speed acoustic structure 910.

[0070] In addition, it can be seen in this embodiment that when other parameters (e.g., equivalent sound speed, first sound path, second sound path, and third sound path) are the same, the second phase shift between the first sound and the second sound is negatively correlated with the frequency. The higher the frequency, the smaller the second phase shift between the first sound and the second sound; the lower the frequency, the larger the second phase shift between the first sound and the second sound.

[0071] Fig.10 It is an exemplary structural diagram of the sound-producing part shown in some embodiments of this specification. Fig.10 The sound generating part 1000 shown in FIG. Figure 5A The structure of the sound generating part 500 shown is substantially the same, except that the acoustic structure is different. Fig.10 As shown, an expanded acoustic structure 1001 may be provided in the first cavity 520 and / or the second cavity 530 of the sound-emitting part 1000. The expanded acoustic structure 1001 may change (for example, expand) the cross-sectional area of ​​the first cavity 520 or the second cavity 530 at different positions on the sound transmission path. When a sound wave propagates in a waveguide (that is, an air waveguide formed by the first cavity 520 or the second cavity 530), if the cross-sectional area of ​​the waveguide at different positions on the sound transmission path changes, the sound wave will be reflected at the position where the cross-sectional area suddenly changes, which means that the equivalent impedance of the medium has changed. Correspondingly, parameters related to the equivalent impedance (such as equivalent sound velocity, equivalent density, etc.) will also change accordingly, thereby causing the phase of the sound wave to change. For example, the effect of the expanded acoustic structure 1001 on the change in the equivalent sound velocity is mainly related to the ratio of the cross-sectional area of ​​the second cavity 530 after expansion by the expanded acoustic structure 1001 to the original cross-sectional area of ​​the second cavity 530. In some embodiments, the actual equivalent sound speed may be obtained through simulation or experimental testing.

[0072] In this embodiment, the expansion acoustic structure 1001 is set in the second cavity 530 as an example for description. Fig.10 As shown, the expansion acoustic structure 1001 can be disposed on two opposite side walls of the second cavity 530, and the expansion acoustic structure 1001 causes a sudden change in the cross-sectional area of ​​the second cavity 530 before and after a specific position on the sound transmission path. In some embodiments, the expansion acoustic structure 1001 can be an expansion cavity. The structural shape of the expansion cavity can be Fig.10 In other embodiments, the cross-sectional area of ​​the expansion acoustic structure 1001 may also be other shapes, such as a triangle, a trapezoid, etc. The structural shape of the expansion cavity may be reasonably set according to the second phase difference between the first sound and the second sound.

[0073] like Fig.10 As shown, the sound waves radiated from the front side of the acoustic driver 510 radiate from the first sound outlet 540 to the outside, and the distance traveled by the sound waves is the first sound path L1 The sound waves radiated from the rear side of the acoustic driver 510 are radiated from the second sound outlet 825 to the outside through the expanded acoustic structure 1001 and the second cavity 530. The distance traveled by the sound waves is the second sound path L 2 Among them, the first sound path L 1 The speed of sound in is the normal speed of sound c, and the second sound path L 2 The sound speed in is the equivalent sound speed c'. The phase delay between the first sound radiated from the first sound outlet 540 and the second sound radiated from the second sound outlet 550 is: Wherein, c represents the normal sound speed, and c' represents the equivalent sound speed in the expanded acoustic structure 1001. Therefore, the second phase offset α between the first sound and the second sound is: α=-2πf·Δt. (14)

[0074] It can be seen from this that the actual output second phase shift α of the first sound and the second sound can be controlled by setting an expanded acoustic structure 1001 in the cavity to control the equivalent sound speed of the sound wave propagating in the cavity.

[0075] In addition, it can be seen in this embodiment that when other parameters (e.g., the first sound path, the second sound path, and the equivalent sound velocity) are the same, the second phase shift between the first sound and the second sound is negatively correlated with the frequency. The higher the frequency, the smaller the second phase shift between the first sound and the second sound; the lower the frequency, the larger the second phase shift between the first sound and the second sound.

[0076] Fig.11 It is an exemplary structural diagram of the sound-producing part shown in some embodiments of this specification. Fig.11 The sound generating part 1100 shown in FIG. Figure 5A The structure of the sound generating part 500 shown is substantially the same, except that the acoustic structure is different. Fig.11 As shown, a sound absorbing structure 1101 may be provided in the first cavity 520 and / or the second cavity 530 of the sound-emitting part 1100. In some embodiments, the sound absorbing structure 1101 may have a resonant frequency. The modulation of the sound near the resonant frequency of the sound absorbing structure 1101 (e.g., phase modulation) may be utilized to control the actual output phase difference of the two sound waves. In some embodiments, the sound absorbing structure 1101 may be a Helmholtz resonant cavity. In some embodiments, the sound absorbing structure 1101 may be a micro-perforated plate resonator. In some embodiments, the sound absorbing structure 1101 may be a 1 / 4 wavelength tube resonator.

[0077] In this embodiment, the sound absorbing structure 1101 is disposed in the second cavity 530 as an example for description. The sound absorbing structure 1101 can be disposed on the side wall of the second cavity 530 and be acoustically connected to the second cavity 530. Taking the Helmholtz resonant cavity as an example, its resonant frequency f 0 Can be:

[0078] Wherein, M represents the acoustic mass (mainly related to the nozzle parameters of the Helmholtz resonator), and C represents the acoustic capacity (mainly related to the cavity parameters at the rear end of the Helmholtz resonator).

[0079] In the embodiment of the present specification, a method for measuring the second phase offset α may be: placing a sound source at the sound entrance of the acoustic structure (e.g., phase tube, sound outlet tube) at the second sound outlet, placing a probe at the second sound outlet, measuring the first phase at the second sound outlet, the first phase being the phase of the sound after passing through the acoustic structure; placing the same sound source at the sound exit of the acoustic structure at the second sound outlet, placing a probe at the second sound outlet to measure the second phase, the second phase being the phase of the sound without passing through the acoustic structure. The second phase offset α caused by the acoustic structure is calculated based on the first phase and the second phase.

[0080] Another measurement method for the second phase offset α can be: taking an acoustic driver (such as a diaphragm) as a sound source, placing a first probe at the first sound outlet, measuring the first phase at the first sound outlet, and taking the first phase plus 180° as the phase when no acoustic structure is set at the second sound outlet and the second cavity; setting a second probe at the second sound outlet, measuring the second phase at the second sound outlet, where the second phase is the phase when an acoustic structure is set in the second sound outlet or in the second cavity, and calculating the difference between the phase value of the first phase plus 180° and the second phase, which is the value of the second phase offset α caused by the acoustic structure.

[0081] By setting an acoustic structure in the sound outlet and / or cavity, the second phase offset α can be adjusted by adjusting the parameters of the acoustic structure to achieve the adjustment of the phase of sounds in different frequency bands, so that the second phase offset α can meet the requirements of different frequencies. In the embodiment of this specification, the target frequency is 3000 Hz, and the range of the second phase offset α caused by the acoustic structure can be 0 to 2π. In some embodiments, the target frequency is 3000 Hz, and the range of the second phase offset α caused by the acoustic structure can be 30° to 180°. In some embodiments, the target frequency is 3000 Hz, and the range of the second phase offset α caused by the acoustic structure can be 60° to 120°.

[0082] According to the above, at the second sound outlet, the phase difference between the third sound and the second sound is 180°+α-β. In order to weaken the sound at the second sound outlet 550 away from the ear canal opening and reduce the sound leakage of the acoustic output device, the second phase shift α can be adjusted by setting an acoustic structure, and the first phase shift β can be adjusted by setting a partition, so that the second sound and the third sound can be superimposed and canceled. That is, by adjusting the range of α-β, the phase difference between the third sound and the second sound is around 180°, so as to weaken the sound at the second sound outlet 550 away from the ear canal opening and reduce the sound leakage of the acoustic output device.

[0083] In some embodiments, by adjusting the parameters of the acoustic structure and the baffle, the range of α-β at the target frequency can be -30° to 30°. Preferably, the range of α-β is -20° to 20°. Preferably, the range of α-β is -10° to 10°. Preferably, the range of α-β is -5° to 5°. Preferably, the value of α-β is 0.

[0084] Figure 12-13 is a schematic diagram of the radiated sound field of the acoustic output device corresponding to the range of α-β shown in some embodiments of this specification. Fig.12 is a schematic diagram of the radiation sound field of the acoustic output device corresponding to 0<α-β≤10, Fig.13 This is a schematic diagram of the radiation sound field of the acoustic output device corresponding to -10≤α-β<0. Fig.12 , when 0<α-β≤10, the radiation sound field diagram of the acoustic output device is similar to a cardioid, without side lobes, and the difference between the sound pressure level of the sound at the first sound outlet and the sound pressure level of the sound at the second sound outlet can be greater than or equal to 20dB, and the acoustic output device has good directivity. Fig.13 When -10≤α-β<0, the radiation sound field diagram of the acoustic output device has side lobes, but it can also ensure that the difference between the sound pressure level of the sound at the first sound outlet and the sound pressure level of the sound at the second sound outlet is greater than or equal to 20dB, and the acoustic output device has good directivity.

[0085] According to the above, at the first sound outlet 540, the phase difference between the fourth sound and the first sound is 180°+α+β. In order to enhance the sound at the first sound outlet 540 pointing to the ear canal opening, the second phase shift α can be adjusted by setting an acoustic structure, and the first phase shift β can be adjusted by setting a partition, so that the first sound and the fourth sound can be superimposed and enhanced. That is, by adjusting the range of α+β, the phase difference between the first sound and the fourth sound is away from 180° (for example, near 0° or 360°), so as to enhance the sound at the first sound outlet 540 facing the ear canal opening and improve the listening effect.

[0086] In some embodiments, by adjusting the parameters of the acoustic structure and the baffle, the range of α+β at the target frequency can be 150° to 210°. Preferably, the range of α+β is 160° to 200°. Preferably, the range of α+β is 170° to 190°. Preferably, the range of α+β is 175° to 185°. Preferably, the value of α+β is 180°.

[0087] In some embodiments, in order to ensure that the sound at the first sound outlet 540 is enhanced and the sound at the second sound outlet 550 is weakened, the range of α+β and the range of α-β can be comprehensively considered. In some embodiments, by adjusting the parameters of the acoustic structure and the baffle, the range of α+β can be 150° to 210°, and the range of α-β can be -30° to 30°. Preferably, by adjusting the parameters of the acoustic structure and the baffle, the range of α+β can be 160° to 200°, and the range of α-β can be -20° to 20°. Preferably, by adjusting the parameters of the acoustic structure and the baffle, the range of α+β can be 170° to 190°, and the range of α-β can be -10° to 10°. Preferably, by adjusting the parameters of the acoustic structure and the baffle, the range of α+β can be 175° to 185°, and the range of α-β can be -5° to 5°. Preferably, by adjusting the parameters of the acoustic structure and the baffle, α=β=90°. Fig.14 1 is a schematic diagram of the radiated sound field of the acoustic output device corresponding to when α=β=90° according to some embodiments of this specification. Fig.14 As shown, when α=β=90°, the radiated sound field of the acoustic output device is cardioid, with better directivity, which can enhance the sound at the sound outlet (such as the first sound outlet 540) pointing to the ear canal opening of the listener, and weaken the sound at the sound outlet (such as the second sound outlet 550) away from the ear canal opening.

[0088] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0089] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0090] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0091] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0092] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0093] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this specification are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the contents of this specification, documents that limit the broadest scope of the claims of this specification (currently or later attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and / or use of terms in this specification shall prevail.

[0094] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. An acoustic output device, characterized in that: include: A sound-producing part, the sound-producing part comprising: Acoustic driver; A shell, the shell having a first cavity and a second cavity acoustically coupled to the acoustic driver, a first sound outlet hole is provided in the first cavity, a second sound outlet hole is provided in the second cavity, and the acoustic driver radiates sound outward through the first sound outlet hole and the second sound outlet hole respectively; wherein, There is a first phase shift in the sound transmitted between the first sound outlet hole and the second sound outlet hole, and an acoustic structure is provided in the first cavity or the second cavity, and the acoustic structure causes the passing sound to produce a second phase shift at a target frequency; the difference between the first phase shift and the second phase shift ranges from -30° to 30°.

2. The acoustic output device according to claim 1, characterized in that: The target frequency is within the range of 500 Hz to 3000 Hz.

3. The acoustic output device according to claim 1, characterized in that: A partition is provided on the outer surface of the shell, one end of the partition is connected to the outer surface of the shell, and the other end of the partition is a free end and extends in a direction away from the shell.

4. The acoustic output device according to claim 3, characterized in that: The height of the partition is less than 2 cm.

5. The acoustic output device according to claim 3, characterized in that: The partition is a retractable structure or a detachable structure.

6. The acoustic output device according to claim 1, characterized in that: The acoustic structure includes a phase tube, and a plurality of grids are arranged on the inner wall of the phase tube, and the number of the grids is greater than or equal to 2.

7. The acoustic output device according to claim 1, characterized in that: The acoustic structure comprises a sound outlet pipe, the inner wall of which is inlaid with a film, and the number of layers of the film is positively correlated with the magnitude of the second phase shift generated by the sound outlet pipe.

8. The acoustic output device according to claim 7, characterized in that: The number of layers of the film is not less than 2.

9. The acoustic output device according to claim 7 or 8, characterized in that: The median mass of the film is 1.9 mg to 4.9 mg.

10. The acoustic output device according to any one of claims 1 to 9, characterized in that: The target frequency is 3000 Hz, and the first phase offset is within the range of 37.8° to 163.8°.

11. The acoustic output device according to any one of claims 1 to 9, characterized in that: The target frequency is 3000 Hz, and the second phase offset ranges from 0 to 180 degrees.

12. The acoustic output device according to claim 1, characterized in that: The sum of the first phase offset and the second phase offset is within a range of 150° to 210°.

13. An acoustic output device, characterized in that: include: A sound-producing part, the sound-producing part comprising: Acoustic driver; A shell, the shell having a first cavity and a second cavity acoustically coupled to the acoustic driver, a first sound outlet hole is provided in the first cavity, a second sound outlet hole is provided in the second cavity, and the acoustic driver radiates sound outward through the first sound outlet hole and the second sound outlet hole respectively; wherein, There is a first phase shift in the sound transmitted between the first sound outlet hole and the second sound outlet hole, and an acoustic structure is provided in the first cavity or the second cavity, and the acoustic structure causes the passing sound to produce a second phase shift at a target frequency; the sum of the first phase shift and the second phase shift is within the range of 150° to 210°.

14. The acoustic output device according to claim 13, characterized in that: The target frequency is within the range of 500 Hz to 3000 Hz.

15. The acoustic output device according to claim 13, characterized in that: A partition is provided on the outer surface of the shell, one end of the partition is connected to the outer surface of the shell, and the other end of the partition is a free end and extends in a direction away from the shell.

16. The acoustic output device according to claim 15, characterized in that: The height of the partition is less than 2 cm.

17. The acoustic output device according to claim 15, characterized in that: The partition is a retractable structure or a detachable structure.

18. The acoustic output device according to claim 13, characterized in that: The acoustic structure includes a phase tube, and a plurality of grids are arranged on the inner wall of the phase tube, and the number of the grids is greater than or equal to 2.

19. The acoustic output device according to claim 13, characterized in that: The acoustic structure comprises a sound outlet pipe, the inner wall of which is inlaid with a film, and the number of layers of the film is positively correlated with the magnitude of the second phase shift generated by the sound outlet pipe.

20. The acoustic output device according to claim 19, characterized in that The number of layers of the film is not less than 2.

21. The acoustic output device according to claim 19 or 20, characterized in that: The median mass of the film is 1.9 mg to 4.9 mg.

22. The acoustic output device according to any one of claims 13 to 21, characterized in that: The target frequency is 3000 Hz, and the first phase offset is within the range of 37.8° to 163.8°.

23. The acoustic output device according to any one of claims 13 to 21, characterized in that: The target frequency is 3000 Hz, and the second phase offset is within the range of 0 to 180 degrees.

24. The acoustic output device according to claim 13, characterized in that The difference between the first phase offset and the second phase offset is in the range of -30° to 30°.

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