Sound cavity structure of earphone and earmuff type earphone

Abstract

The invention relates to the technical field of earphones, in particular to an acoustic cavity structure of an earphone and an earmuff type earphone. The sound cavity structure comprises a shell, an ear pad, a cover plate, a loudspeaker assembly and a printed circuit board, and the shell and the ear pad are configured in a way that the shell and the ear pad jointly form a closed sound cavity space in a wearing state, so that external environment noise is directly isolated, and the physical sound insulation performance is improved. A first rear cavity is defined by the loudspeaker assembly and the shell, a second rear cavity is defined by the cover plate, the outer edge of the loudspeaker assembly and the shell, the printed circuit board is arranged in the second rear cavity, and a front cavity is defined by the ear pad, the shell, the cover plate and the loudspeaker assembly. The first rear cavity, the second rear cavity and the front cavity are communicated with one another through a pressure regulating channel. The loudspeaker diaphragm movement blocking and acoustic performance degradation caused by the abnormal air pressure of the first rear cavity are avoided, and the stability of the loudspeaker effect is ensured. The printed circuit board is arranged in the second rear cavity, so that the printed circuit board is prevented from reflecting and scattering sound waves, and the problem of audio distortion caused by a circuit board arranged in a traditional front cavity is solved.

Description

Technical Field

[0001] This invention relates to the field of headphone technology, and more particularly to a headphone acoustic cavity structure and a headphone. Background Technology

[0002] Noise pollution has become a widespread problem. In complex noisy environments, people urgently need quiet spaces to improve concentration, work efficiency, or protect their hearing. Therefore, personal hearing protection equipment with noise-canceling functions, especially noise-canceling headphones, has become the preferred choice.

[0003] Currently, noise-canceling headphones on the market are mainly divided into two categories: physical noise-canceling (passive noise-canceling) headphones and active noise-canceling headphones. Physical noise-canceling headphones mainly rely on the physical materials and structure of the earcups and ear pads to isolate sound. They are effective at isolating mid-to-high frequency noise, with experiments showing an average reduction of 20-25 dB in high sound pressure level noise. However, their ability to isolate low-frequency noise (such as engine roar and air conditioner noise) is limited, which is an inherent technical bottleneck of the physical noise isolation principle.

[0004] Active noise-canceling headphones were developed to address the aforementioned shortcomings. They use built-in microphones to collect ambient noise, and a processing chip generates out-of-phase sound waves that are output through a speaker, thus canceling out low-frequency noise and achieving superior noise reduction depth and breadth. Common active noise-canceling technologies include feedforward, feedback, and hybrid types. In terms of acoustic design, to ensure proper speaker operation and wearing comfort, active noise-canceling headphones typically employ the following approach: A damping vent (also called a pressure relief vent) is created in the headphone shell to connect the speaker's rear cavity to the external environment, balancing internal and external air pressure and releasing back waves from the speaker, thereby preventing diaphragm movement from being obstructed and improving low-frequency sound quality. To reduce the negative impact of this pressure relief vent on sound insulation performance, damping components (such as porous sponge, acoustic mesh, etc.) are usually added inside or at the vent opening to attenuate some of the noise transmitted through the vent. However, even with added damping components, sound waves cannot be completely blocked, weakening the headphones' passive noise cancellation (physical sound insulation) capability.

[0005] Meanwhile, the printed circuit boards of traditional over-ear headphones are usually placed directly inside the front cavity. The surface of the board and the messy cable layout can easily cause reflection, scattering and interference of the sound waves emitted by the speaker, which can damage the stability of the acoustic space. In addition, the cables themselves may resonate with the speaker diaphragm, which can cause minor noise and audio distortion, affecting the overall listening experience. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an acoustic cavity structure and headphones, which solves the technical problem that the physical sound insulation (passive noise reduction) capability of traditional active noise-canceling headphones is weakened due to the need to open external pressure relief holes.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] This invention provides an acoustic cavity structure for an earphone. The acoustic cavity structure includes a housing, an ear pad disposed at the front end of the housing, a cover plate disposed within the housing, a speaker assembly, and a printed circuit board. The housing and ear pad are configured such that, in the wearing state, they together form a sealed acoustic cavity space. The speaker assembly and the housing enclose a first rear cavity. The cover plate is disposed between the housing and the ear pad, and together with the outer edge of the speaker assembly and the housing, it encloses a second rear cavity. The printed circuit board is disposed within the second rear cavity. The ear pad, housing, cover plate, and speaker assembly enclose a front cavity. The first rear cavity, the second rear cavity, and the front cavity are interconnected via a voltage regulation channel.

[0011] Preferably, the pressure regulating channel includes: a first pressure regulating channel disposed on the speaker assembly to connect the first rear cavity and the second rear cavity; and a second pressure regulating channel disposed on the cover plate to connect the second rear cavity and the front cavity.

[0012] Preferably, the horn assembly includes a horn mounting base and a horn body disposed on the horn mounting base; the diaphragm of the horn body, the horn mounting base, and the housing enclose a first rear cavity; the circumferential sidewall of the horn mounting base, the housing, and the cover plate enclose a second rear cavity.

[0013] Preferably, the first pressure regulating channel includes at least one pressure relief hole opened on the horn mounting base to connect the second rear cavity and the first rear cavity.

[0014] Preferably, the first pressure regulating channel further includes a damping component disposed on the horn mounting base; the damping component is disposed corresponding to the pressure relief hole, and the damping component includes a first damping plate and a second damping plate; the first damping plate and the second damping plate respectively cover both sides of the pressure relief hole.

[0015] Preferably, the second pressure regulating channel includes at least one through hole formed on the cover plate to connect the front cavity and the second rear cavity.

[0016] Preferably, the second pressure regulating channel further includes a third damping plate; the third damping plate is disposed corresponding to the through hole; the third damping plate is located in the front cavity and covers the through hole.

[0017] Preferably, the diameter of the pressure relief hole and / or through hole is less than 3 mm.

[0018] Preferably, it further includes a sealing element; the sealing element is disposed between the mating surfaces of the cover plate and the housing.

[0019] The present invention also provides an over-ear headphone, including the acoustic cavity structure of the headphone described above.

[0020] (III) Beneficial Effects

[0021] The beneficial effects of this invention are:

[0022] The present invention discloses an acoustic cavity structure for headphones, comprising a housing, an ear pad disposed at the front end of the housing, and a cover plate, a speaker assembly, and a printed circuit board disposed within the housing. The housing and ear pad are configured such that, in the wearing state, they together form a sealed acoustic cavity space. Because the housing and ear pad form a sealed acoustic cavity space, external environmental noise is directly isolated, solving the problem of weakened passive noise cancellation capability caused by external pressure relief holes in traditional headphones, and improving physical sound insulation performance.

[0023] The speaker assembly and housing enclose a first rear cavity. A cover plate is positioned between the housing and the earpad, and together with the outer edge of the speaker assembly and the housing, forms a second rear cavity. A printed circuit board is located within the second rear cavity. The earpad, cover plate, and speaker assembly together form a front cavity. The first, second, and front cavities are interconnected via a pressure regulating channel. The synergistic effect of the front and second rear cavities buffers pressure changes in the first rear cavity caused by temperature differences, preventing abnormal air pressure in the first rear cavity from hindering the speaker diaphragm's movement and degrading acoustic performance, thus ensuring the stability of the speaker's performance. Simultaneously, the hierarchically connected chamber structure allows pressure in the first rear cavity to be gradually transmitted to the front cavity through the second rear cavity, preventing sudden pressure changes from directly affecting the ear and eliminating the need for an external pressure relief port, thus balancing wearing comfort and passive noise cancellation performance.

[0024] The sound waves from the speaker assembly enter the front cavity directly, reducing sound wave reflection interference within the cavity. The printed circuit board (PCB) is located in the second rear cavity, away from the acoustic area on the ear side, avoiding sound wave reflection and scattering by the PCB and solving the audio distortion problem caused by the traditional front cavity PCB placement. Simultaneously, the cover plate isolates the PCB in a separate second rear cavity, forming a physical protective barrier. This effectively prevents external dust and moisture from entering the PCB area from the earpad side or shell gaps, providing waterproof and dustproof protection for the PCB, extending its lifespan and the overall reliability of the headphones. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a single-sided earphone in this embodiment;

[0026] Figure 2 for Figure 1 A schematic diagram of the structure where the middle ear pad is separated from the shell;

[0027] Figure 3 for Figure 1 A schematic diagram of the decomposition process;

[0028] Figure 4 for Figure 1 A longitudinal sectional view;

[0029] Figure 5 This is a structural schematic diagram of the cover plate and the horn assembly;

[0030] Figure 6 for Figure 5 A longitudinal sectional view;

[0031] Figure 7 This is a schematic diagram of the structure of an over-ear headphone.

[0032] [Explanation of Labels in the Attached Image]

[0033] 1: Shell;

[0034] 2: Ear pads;

[0035] 3: Speaker assembly; 31: Speaker mounting bracket; 32: Speaker body; 33: First sealing ring; 34: Second sealing ring;

[0036] 4: First pressure regulating channel; 41: Pressure relief hole; 42: Damping assembly; 421: First damping plate; 422: Second damping plate;

[0037] 5: Cover plate;

[0038] 6: Second voltage regulating channel; 61: Connecting hole; 62: Third damping plate;

[0039] 7: Seals;

[0040] 8: Printed circuit boards;

[0041] A: First posterior cavity; B: Second posterior cavity; C: Anterior cavity. Detailed Implementation

[0042] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] like Figures 1-6 As shown, this embodiment provides a sound cavity structure for headphones, such as... Figure 2 As shown, the acoustic cavity structure includes a housing 1, an ear pad 2 disposed at the front end of the housing 1, a cover plate 5 disposed inside the housing 1, a speaker assembly 3, and a printed circuit board 8.

[0045] The shell 1 and ear pad 2 are configured such that, when worn, they together form a sealed acoustic cavity. Because the shell 1 and ear pad 2 form a sealed acoustic cavity, external ambient noise can be directly isolated. Structurally, this avoids the technical defect of traditional headphones where the passive noise reduction capability is weakened due to the external pressure relief hole 41, and significantly improves physical sound isolation performance.

[0046] like Figure 4 As shown, the speaker assembly 3 and the housing 1 enclose a first rear cavity A. A cover plate 5 is positioned between the housing 1 and the ear pad 2, and together with the outer edge of the speaker assembly 3 and the housing 1, forms a second rear cavity B. A printed circuit board 8 is disposed within the second rear cavity B. The ear pad 2, housing 1, cover plate 5, and speaker assembly 3 enclose a front cavity C. The first rear cavity A, the second rear cavity B, and the front cavity C are interconnected via a pressure regulating channel. Through this channel, the front cavity C and the second rear cavity B can collaboratively buffer pressure changes in the first rear cavity A caused by environmental temperature differences, preventing abnormal air pressure in the first rear cavity A from hindering the movement of the speaker diaphragm and degrading acoustic performance, thus ensuring the stability of the speaker effect. Simultaneously, the hierarchically connected chamber structure allows the pressure in the first rear cavity A to be gradually transmitted to the front cavity C through the second rear cavity B, avoiding the pressure shock directly acting on the ear and eliminating the need for an external pressure relief hole 41, thus balancing wearing comfort and passive noise reduction performance.

[0047] The sound waves from the speaker assembly 3 enter the front cavity C directly, reducing sound wave reflection and refraction interference within the cavity and ensuring the purity of the acoustic signal. The printed circuit board 8 is located in the second rear cavity B, away from the acoustic area on the ear side, avoiding the reflection and scattering of sound waves by the printed circuit board 8 and its surface components, thus solving the audio distortion problem caused by the traditional circuit board placement in the front cavity B. At the same time, the cover plate 5 isolates the printed circuit board 8 in an independent second rear cavity B, forming a physical protective barrier. This effectively prevents external dust and moisture from entering the area of ​​the printed circuit board 8 from the ear pad 2 side or the gap in the shell 1, achieving waterproof and dustproof protection for the printed circuit board 8, extending the lifespan of the circuit board and the overall reliability of the headphones.

[0048] like Figure 5 As shown, the horn assembly 3 is provided with a first pressure regulating channel 4 that connects the first rear cavity A and the second rear cavity B, and the cover plate 5 is provided with a second pressure regulating channel 6 that connects the second rear cavity B and the front cavity C. The cooperation of these two pressure regulating channels further optimizes the air pressure balance effect.

[0049] like Figure 5 As shown, the speaker assembly 3 includes a speaker mounting base 31 and a speaker body 32 fixed thereon, as... Figure 4 As shown, the diaphragm of the speaker body 32 in the speaker assembly 3 divides the internal space of the sealed acoustic cavity into two independent front cavities B and a first rear cavity A. The front cavity B is located in front of the diaphragm, i.e., close to the ear, while the first rear cavity A is located behind the diaphragm.

[0050] like Figure 3 and Figure 5 As shown, in a preferred embodiment, the speaker assembly 3 further includes a first sealing ring 33 and a second sealing ring 34. The first sealing ring 33 is located between the speaker mounting base 31 and the speaker body 32 to achieve a sealed connection between the two. The second sealing ring 34 is located between the speaker mounting base 31 and the housing 1 to achieve a seal between the two. In this embodiment, the speaker mounting base 31 and the cover plate 5 in the speaker assembly 3 are integrally formed. The speaker mounting base 31 protrudes from the middle area of ​​the cover plate 5. The speaker body 32 is disposed on the speaker mounting base 31. The diaphragm of the speaker body 32, the speaker mounting base 31, and the housing 1 enclose to form a first rear cavity A. The circumferential sidewall of the speaker mounting base 31, the housing 1, and the cover plate 5 enclose to form a second rear cavity B. That is, the sound waves of the diaphragm of the speaker body 32 directly enter the front cavity C. The first voltage regulating channel 4 is integrated on the speaker mounting base 31.

[0051] like Figure 5 As shown, the first pressure regulating channel 4 includes a pressure relief hole 41 and a damping assembly 42. At least one pressure relief hole 41 is formed on the speaker mounting base 31 to connect the second rear cavity B and the first rear cavity A. The pressure relief hole 41 serves as the basic structure of the first pressure regulating channel 4, featuring a simple design and low processing difficulty, effectively reducing manufacturing costs. The number and diameter of the pressure relief holes 41 can be adjusted according to actual acoustic requirements, flexibly adapting to the air pressure balance needs of different headphone models.

[0052] like Figure 3 and Figure 6 As shown, the damping assembly 42 is mounted on the speaker mounting base 31 and corresponds one-to-one with the pressure relief hole 41. The damping assembly 42 includes a first damping plate 421 and a second damping plate 422, which respectively cover both sides of the pressure relief hole 41. The two damping plates covering both sides of the pressure relief hole 41 form a bidirectional damping effect. Whether the gas flows from the first rear cavity A to the front cavity B or vice versa, stable damping adjustment can be obtained, ensuring the stability of the air pressure balance and avoiding additional noise generated by airflow impact. The first damping plate 421 and the second damping plate 422 can be made of acoustic damping materials such as tuning paper, tuning mesh, and waterproof and breathable membrane.

[0053] like Figure 6As shown, the second pressure regulating channel 6 is integrated into the cover plate 5. The second pressure regulating channel 6 includes a through hole and a third damping plate 62. At least one through hole is formed on the cover plate 5 to connect the front cavity C and the second rear cavity B. The third damping plate 62 is correspondingly arranged with the second pressure regulating channel 6. The third damping plate 62 is located in the front cavity C and completely covers the through hole. The third damping plate 62 is an acoustic damping material such as tuning paper, tuning mesh, or waterproof and breathable membrane, preferably a waterproof and breathable membrane. The waterproof and breathable membrane can achieve air pressure communication between the chambers while effectively blocking external moisture from entering the acoustic cavity from the ear pad 2 side, realizing the waterproof function of the acoustic cavity structure and preventing the internal precision components from being affected by moisture. At the same time, the third damping plate 62 dampens and adjusts the gas flow between the front cavity C and the second rear cavity B, controls the airflow speed, avoids additional noise caused by airflow impact, and improves the purity of sound quality.

[0054] In this embodiment, the first pressure regulating channel 4 is provided with a pressure relief hole 41 and the second pressure regulating channel 6 is provided with a through hole, the diameter of which is less than 3mm. This hole diameter design can ensure effective air pressure communication between the chambers while avoiding significant weakening of the air spring effect in the chamber, thus ensuring the stability of the speaker's low-frequency response.

[0055] like Figure 3 As shown, the acoustic cavity structure also includes a sealing element 7, which is disposed between the mating surfaces of the cover plate 5 and the housing 1. The sealing element 7 can fill the gap between the cover plate 5 and the housing 1, ensuring the sealing between the front cavity C and the second rear cavity B, preventing air leakage, and further enhancing the overall dustproof and moisture-proof capabilities. The sealing element 7 can be a ring or a sealant.

[0056] To further verify the noise reduction effect of the acoustic cavity structure in this embodiment, the noise reduction amount at different frequency points was tested for headphones using the acoustic cavity structure (internal opening) of this invention and those using a traditional external opening structure, respectively, under physical noise reduction and active noise reduction scenarios. The test data are shown in the table below:

[0057] Table 1. Noise reduction at different frequencies for different types of cavities (unit: dB)

[0058]

[0059] In physical noise reduction scenarios: The acoustic cavity structure (internal opening) in this embodiment has significantly higher noise reduction at all frequency points than the traditional external opening structure, especially in the mid-low frequency range of 250Hz-1000Hz, where the noise reduction is improved by 11dB-17.7dB, which fully demonstrates the enhanced effect of the closed acoustic cavity space on passive sound insulation performance.

[0060] In active noise cancellation scenarios: The acoustic cavity structure (internal opening) in this embodiment has significantly better noise reduction in the mid-to-high frequency band of 1000Hz-2000Hz than the traditional external opening structure (improvement of about 6.7dB-10dB).

[0061] The test data above further proves that the acoustic cavity structure of this embodiment effectively improves the noise reduction performance of the headphones while ensuring wearing comfort, and solves the technical defects of the traditional external opening structure.

[0062] Example 2

[0063] like Figure 7 As shown, this embodiment provides an over-ear headphone, which includes the acoustic cavity structure in Embodiment 1. The over-ear headphone with the above-mentioned acoustic cavity structure does not require an external pressure relief hole 41, and can simultaneously achieve excellent passive noise isolation performance and good wearing comfort.

[0064] These over-ear headphones can be flexibly adapted to active noise cancellation or physical noise cancellation applications according to actual needs. In active noise cancellation scenarios, they can simultaneously achieve excellent passive noise isolation performance and good wearing comfort. In physical noise cancellation scenarios, they can effectively prevent speaker diaphragm deformation, improving wearing comfort and sound quality stability.

[0065] Furthermore, in the over-ear headphones, the sound waves from the speaker assembly 3 directly enter the front cavity C, reducing the interference of sound wave reflection and refraction within the cavity. The printed circuit board 8 is located in the second rear cavity B, away from the acoustic area on the ear side, avoiding the reflection and scattering of sound waves by the printed circuit board 8, thus solving the audio distortion problem caused by the traditional front cavity B circuit board placement. At the same time, the cover plate 5 isolates the printed circuit board 8 in an independent second rear cavity B, forming a physical protective barrier, which can effectively prevent external dust and moisture from entering the area of ​​the printed circuit board 8 from the ear pad 2 side or the gap of the shell 1, achieving waterproof and dustproof protection for the printed circuit board 8, extending the service life of the circuit board and the overall reliability of the headphones.

[0066] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0067] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0068] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0069] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0070] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A sound cavity structure for an earphone, characterized in that, The acoustic cavity structure includes a housing (1), an ear pad (2) disposed at the front end of the housing (1), a cover plate (5), a speaker assembly (3), and a printed circuit board (8) disposed inside the housing (1). The housing (1) and the ear pad (2) are configured such that, when worn, they together form a sealed acoustic cavity space; The speaker assembly (3) and the housing (1) enclose to form a first rear cavity (A), the cover plate (5) is disposed between the housing (1) and the ear pad (2), and together with the outer edge of the speaker assembly (3) and the housing (1) to form a second rear cavity (B), the printed circuit board (8) is disposed in the second rear cavity (B), and the ear pad (2), the housing (1), the cover plate (5) and the speaker assembly (3) enclose to form a front cavity (C); The first rear cavity (A), the second rear cavity (B), and the front cavity (C) are interconnected via a pressure regulating channel.

2. The acoustic cavity structure of the earphone as described in claim 1, characterized in that: The voltage regulating channel includes: A first pressure regulating channel (4) is provided on the speaker assembly (3) to connect the first rear cavity (A) and the second rear cavity (B). A second pressure regulating channel (6) is provided on the cover plate (5) to connect the second rear cavity (B) and the front cavity (C) to each other.

3. The acoustic cavity structure of the headphones as described in claim 2, characterized in that: The speaker assembly (3) includes a speaker mounting base (31) and a speaker body (32) disposed on the speaker mounting base (31). The diaphragm of the speaker body (32), the speaker mounting base (31) and the housing (1) enclose the first rear cavity (A). The circumferential sidewall of the horn mounting base (31), the housing (1), and the cover plate (5) enclose the second rear cavity (B).

4. The acoustic cavity structure of the headphones as described in claim 3, characterized in that: The first pressure regulating channel (4) includes at least one pressure relief hole (41) opened on the horn mounting base (31) to connect the second rear cavity (B) and the first rear cavity (A).

5. The acoustic cavity structure of the headphones as described in claim 4, characterized in that: The first voltage regulating channel (4) also includes a damping component (42) disposed on the horn mounting base (31); The damping component (42) is provided corresponding to the pressure relief hole (41), and the damping component (42) includes a first damping plate (421) and a second damping plate (422). The first damping plate (421) and the second damping plate (422) respectively cover both sides of the pressure relief hole (41).

6. The acoustic cavity structure of the earphone as described in any one of claims 4-5, characterized in that: The second pressure regulating channel (6) includes at least one through hole (61) opened on the cover plate (5) to connect the front cavity (C) and the second rear cavity (B).

7. The acoustic cavity structure of the headphones as described in claim 6, characterized in that: The second voltage regulating channel (6) also includes a third damping plate (62); The third damping plate (62) is provided correspondingly to the through hole (61); The third damping plate (62) is located in the front cavity (C) and covers the through hole (61).

8. The acoustic cavity structure of the headphones as described in claim 6, characterized in that: The diameter of the pressure relief hole (41) and / or the through hole (61) is less than 3 mm.

9. The acoustic cavity structure of the earphone as described in any one of claims 1-8, characterized in that: It also includes a seal (7); The sealing element (7) is disposed between the mating surfaces of the cover plate (5) and the housing (1).

10. An over-ear headphone, characterized in that, The acoustic cavity structure of the headphones as described in any one of claims 1-9.

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