Low-frequency noise reduction earmuffs, low-frequency noise reduction headphones and low-frequency noise reduction method

Abstract

The present application discloses a low-frequency noise reduction earmuff, a low-frequency noise reduction headset and a low-frequency noise reduction method. The low-frequency noise reduction earmuff comprises: an earmuff leather, the earmuff leather is used to fit the ear of the user; an earmuff sponge, the earmuff sponge is arranged on the lower side of the earmuff leather, and the earmuff sponge is used to support the earmuff leather; an earmuff bracket, the earmuff bracket is arranged on the lower side of the earmuff sponge, the earmuff bracket is provided with a sound guide cavity, the earmuff bracket is provided with at least one sound guide tube, and the sound guide tube is a conductive cavity connected to the sound guide cavity and passes through the earmuff bracket. By setting the sound guide tube, low-frequency sound waves that are prone to generate low-frequency oscillation noise are filtered out, thereby reducing the generation of low-frequency oscillation noise of the earphone.

Description

Technical Field

[0001] The present application relates to the field of earphone technology, and in particular to a low-frequency noise reduction earmuff, a low-frequency noise reduction earphone and a low-frequency noise reduction method. Background Art

[0002] In the related art, due to differences in head size and ear size among users, the acoustic performance of headphones when worn also varies. Therefore, when some users use noise-cancelling headphones, the headphones are prone to generate low-frequency oscillation noise when the noise-cancelling function is turned on due to changes in the noise-cancelling mechanism and acoustic performance. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a low-frequency noise reduction earmuff, which filters out low-frequency sound waves that are prone to generate low-frequency oscillation noise by setting a sound guide tube, thereby reducing the generation of low-frequency oscillation noise of headphones.

[0004] The present application also proposes a low-frequency noise reduction headset having the above-mentioned low-frequency noise reduction earmuffs and a low-frequency noise reduction method applied to the low-frequency noise reduction headset.

[0005] The low-frequency noise reduction earmuff according to the embodiment of the first aspect of the present application includes: an earmuff leather, the earmuff leather is used to fit the ear of the user; an earmuff sponge, the earmuff sponge is arranged on the lower side of the earmuff leather, and the earmuff sponge is used to support the earmuff leather; an earmuff bracket, the earmuff bracket is arranged on the lower side of the earmuff sponge, the earmuff bracket is provided with a sound guide cavity, the earmuff bracket is provided with at least one sound guide tube, and the sound guide tube is a conducting cavity connected to the sound guide cavity and passes through the earmuff bracket.

[0006] The low-frequency noise reduction earmuffs according to the embodiments of the present application have at least the following beneficial effects: by providing a sound guide tube, low-frequency sound waves that are prone to generate low-frequency oscillation noise are filtered out, thereby reducing the generation of low-frequency oscillation noise in the earphones.

[0007] According to some embodiments of the present application, the earmuff skin is provided with a receiving groove, and the receiving groove is used to receive the earmuff sponge.

[0008] According to some embodiments of the present application, the earmuff sponge is ring-shaped, and the accommodating groove is an annular groove.

[0009] According to some embodiments of the present application, a mesh groove is provided at one end of the sound guide tube close to the sound guide cavity, and the mesh groove is used for installing the sound guide mesh.

[0010] According to some embodiments of the present application, the earmuff sponge is made of memory foam.

[0011] According to some embodiments of the present application, the earmuff bracket is provided with four sound guide tubes, and the four sound guide tubes are distributed symmetrically with respect to the center.

[0012] The low-frequency noise reduction earphones according to the second aspect of the present application include: the low-frequency noise reduction earmuffs of the first aspect; an earphone shell, the earphone shell is connected to the earmuff bracket of the low-frequency noise reduction earmuffs, the earphone shell is provided with a sound outlet and a vent, the sound outlet is located at the connection between the earphone shell and the low-frequency noise reduction earmuffs; a speaker, the speaker is accommodated in the earphone shell, the speaker includes a diaphragm, the diaphragm is used to vibrate and make sound; a noise reduction module, the noise reduction module is accommodated in the earphone shell, the noise reduction module is connected to the speaker, and the noise reduction module is used to eliminate noise.

[0013] According to the low-frequency noise reduction method of the third aspect embodiment of the present application, applied to the low-frequency noise reduction headphones of the second aspect embodiment mentioned above, it includes: obtaining the single-body resonance frequency of the speaker; obtaining the sound quality of the sound guide tube; and obtaining the low-frequency resonance frequency of the low-frequency noise of the headphones based on the single-body resonance frequency and the sound quality.

[0014] According to some embodiments of the present application, the step of obtaining the sound quality of the sound guide tube is specifically: obtaining the radius of the sound outlet hole, the center distance of the sound outlet holes, the length of the sound outlet holes and the number of sound outlet holes; and obtaining the sound quality according to the radius of the sound outlet hole, the center distance of the sound outlet holes, the length of the sound outlet holes and the number of sound outlet holes.

[0015] According to some embodiments of the present application, the step of obtaining the low-frequency resonance frequency of the low-frequency noise of the headphone according to the monomer resonance frequency and the sound mass is specifically: obtaining the air hole compliance, earmuff compliance, speaker compliance and equivalent vibration area of ​​the headphone diaphragm; and obtaining the low-frequency resonance frequency according to the monomer resonance frequency, the sound mass, the air hole compliance, the earmuff compliance, the speaker compliance and the equivalent vibration area.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 An exploded view of an embodiment of the low-frequency noise reduction earmuffs of the present application;

[0019] Figure 2 A cross-sectional view of an embodiment of the earmuff bracket of the present application;

[0020] Figure 3A schematic diagram of an embodiment of the low-frequency noise reduction earphone of the present application;

[0021] Figure 4 This is a flow chart of an embodiment of the low-frequency noise reduction method of the present application;

[0022] Figure 5 for Figure 4 A flowchart of an embodiment of step S200;

[0023] Figure 6 for Figure 4 A flowchart of an embodiment of step S300;

[0024] Figure 7 This is a noise reduction effect diagram of an embodiment of the low-frequency noise reduction earmuffs of the present application.

[0025] Reference numerals:

[0026] Earmuff leather 100, earmuff sponge 200, earmuff bracket 300, sound guide cavity 310, sound guide tube 320, mesh cloth groove 330;

[0027] Low-frequency noise reduction earmuffs 400 and earphone housing 500 . DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0029] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0031] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0032] The low-frequency noise reduction earmuffs of the embodiment of the present application can be used for head-mounted hybrid noise reduction headphones with active noise reduction function. The principle of active noise reduction is to emit sound waves with completely opposite phases according to the specified noise sound waves, so that the two sound waves cancel each other when they meet, thereby eliminating the noise. After years of development, the basic structure of head-mounted hybrid noise reduction headphones has not changed much, but the functions of wearing comfort and appearance structure are constantly being improved. Head-mounted hybrid noise reduction headphones include feedforward noise reduction and feedback noise reduction functions. The front noise reduction microphone is placed outside the headset to pick up and process external medium and high frequency noise. The feedback noise reduction microphone is located between the front cavity of the headset and the earmuff to collect and process low-frequency noise. The collected noise is close to the noise heard by the user. After the noise signal is collected, it will be transmitted to the processor for noise reduction processing. The feedback noise reduction microphone will also continuously detect whether there is residual noise in the sound after the noise reduction processing, and achieve the best noise reduction effect by continuously comparing multiple noise reductions. However, the feedback noise reduction microphone is designed to be placed between the earmuff and the front cavity of the earphone. The earmuff size and head-mounted clamping force designed based on existing specifications are difficult to meet the needs of all users. Therefore, when the head and ear sizes of users differ, the acoustic performance of the earphones will also vary due to the head-mounted clamping force and the leakage resistance of the earmuffs. When some users use head-mounted hybrid noise reduction headphones, the headphones are prone to low-frequency oscillation noise when the active noise reduction function is turned on due to the noise reduction mechanism and changes in the acoustic performance of the headphones.

[0033] Based on this, the present application proposes a low-frequency noise reduction earmuff, a low-frequency noise reduction headphone and a low-frequency noise reduction method, which filters out low-frequency sound waves that are prone to generate low-frequency oscillation noise by setting a sound guide tube, thereby reducing the generation of low-frequency oscillation noise in the headphone.

[0034] Some embodiments, see Figure 1 The low-frequency noise reduction earmuff includes: an earmuff leather 100, an earmuff sponge 200 and an earmuff bracket 300, the earmuff leather 100 is used to fit the user's ear; the earmuff sponge 200 is arranged on the lower side of the earmuff leather 100, and the earmuff sponge 200 is used to support the earmuff leather 100; the earmuff bracket 300 is arranged on the lower side of the earmuff sponge 200, the earmuff bracket 300 is provided with a sound guide cavity 310, and the earmuff bracket 300 is provided with at least one sound guide tube 320, which is a conducting cavity connected to the sound guide cavity 310 and passes through the earmuff bracket 300.

[0035] The earmuff sponge 200 is wrapped in the earmuff leather 100 and fixed on the earmuff bracket 300 by glue. The earmuff sponge 200 is used to reduce the pressure on the user's ears and improve the comfort of the user when using the earphone. The sound guide cavity 310 is a cavity that conducts sound waves when the user uses the earphone, and is usually located in the center of the earmuff. The sound guide tube 320 is a conductive cavity that connects the sound guide cavity 310 and passes through the earmuff bracket 300, which connects the sound guide cavity 310 with the outside of the earphone, so as to filter out some low-frequency sound waves in the earphone that are prone to low-frequency oscillation noise. The cross-sectional area and length of the sound guide tube 320 can be adjusted according to the volume of the sound guide cavity 310 and the speaker parameters.

[0036] The low-frequency noise reduction earmuffs of the embodiment of the present application have at least the following beneficial effects: by providing the sound guide tube 320, low-frequency sound waves that are prone to generate low-frequency oscillation noise are filtered out, thereby reducing the generation of low-frequency oscillation noise of the earphones.

[0037] In some embodiments, the earmuff leather 100 is provided with a receiving groove, and the receiving groove is used to receive the earmuff sponge 200. The earmuff sponge 200 is usually not a flat sponge, but a conductive cavity is provided in the middle, and the conductive cavity is connected to the sound guide cavity 310 of the earphone bracket for conducting sound waves. It can be understood that the earmuff leather 100 is not a flat leather layer, but only wraps the surrounding parts of the earmuff sponge 200 to form a concave groove.

[0038] In some embodiments, the earmuff sponge 200 is annular, and the receiving groove is an annular groove. In the relevant market, earmuffs are usually annular or elliptical, which can fit the user's ears well without causing too much pressure. In one embodiment, the earmuff sponge 200 can also be a cylinder, and in this case, the earmuff leather 100 is also a flat leather layer.

[0039] Some embodiments, see Figure 1 and Figure 2 The end of the sound guide tube 320 close to the sound guide cavity 310 is provided with a mesh groove 330, and the mesh groove 330 is used to install the sound guide mesh. Because the sound guide tube 320 connects the sound guide cavity 310 with the outside of the earphone, dust in the outside air can easily enter the sound guide cavity 310 through the sound guide tube 320, making the sound quality of the earphone worse and more noise is easily generated. Therefore, a sound guide mesh is set at one end of the sound guide tube 320 to prevent dust from entering the inside of the earmuff. At the same time, the thickness and density of the sound guide mesh can be set and different materials can be selected to adjust the low-frequency sensitivity of the earphone.

[0040] In some embodiments, the earmuff sponge 200 is made of memory sponge. Memory sponge refers to a polyether polyurethane foam sponge with slow rebound mechanical properties, which is a characteristic sponge. Memory sponge has leading performance in mechanical aspects such as absorbing impact force, reducing vibration, and releasing low rebound force. In addition, memory sponge provides uniform surface pressure distribution, adapts to the surface shape of external pressure through stress relaxation, and reduces the pressure at the highest point to the minimum, thereby avoiding the discomfort caused by microcirculation compression. In this embodiment, memory sponge is selected as the earmuff sponge 200, which can reduce the pressure on the user's ears caused by the clamping force of the earphone, so that the user will not feel discomfort even after using it for a long time.

[0041] Some embodiments, see Figure 2 The earmuff bracket 300 is provided with four sound guide tubes 320, and the four sound guide tubes 320 are distributed symmetrically around the center. The four sound guide tubes 320 are evenly distributed around the sound guide cavity 310, and the adjacent sound guide tubes 320 are perpendicular to each other. Such a structural design can evenly and effectively filter out low-frequency sound waves that are prone to generate low-frequency oscillation noise. In an illustrative embodiment, the sound guide tubes 320 can also be set to eight, and the eight sound guide tubes 320 are distributed symmetrically with respect to the sound guide cavity 310.

[0042] Some embodiments, see Figure 3 The low-frequency noise reduction earphones include: a low-frequency noise reduction earmuff 400 of any of the above-mentioned embodiments, an earphone shell 500, a speaker and a noise reduction module, the earphone shell 500 is connected to the earmuff bracket 300 of the low-frequency noise reduction earmuff 400, the earphone shell 500 is provided with a sound outlet and a vent, and the sound outlet is located at the connection between the earphone shell 500 and the low-frequency noise reduction earmuff 400; the speaker is accommodated in the earphone shell 500, the speaker includes a diaphragm, and the diaphragm is used to vibrate and make sound; the noise reduction module is accommodated in the earphone shell 500, the noise reduction module is connected to the speaker, and the noise reduction module is used to eliminate noise.

[0043] It should be noted that the headset also includes a control circuit board, which includes many circuit modules, such as a charging module, an audio conversion module, a user interaction module, a processing module, etc. Among them, the noise reduction module is also arranged on the control circuit board and connected with other modules to realize the noise reduction function and enhance the user experience.

[0044] Some embodiments, see Figure 4 The low-frequency noise reduction method is applied to the low-frequency noise reduction headphones of the above embodiment, and the low-frequency noise reduction method includes:

[0045] S100, obtaining a single-body resonance frequency of the speaker;

[0046] S200, obtaining the sound quality of the sound guide tube;

[0047] S300, obtaining a low-frequency resonance frequency of the earphone low-frequency noise according to the monomer resonance frequency and the sound quality.

[0048] For step S100, the speaker, as a sound-generating device in the earphone, also has resonance. Before the speaker is installed in the earphone, its resonance frequency is the single-unit resonance frequency. After the speaker is installed in the earphone, its resonance frequency is the resonance frequency of the earphone, that is, the low-frequency resonance frequency. The sound waves at the low-frequency resonance frequency point will resonate to produce low-frequency oscillation noise. The frequency value of the low-frequency resonance frequency will change with the change of the earphone structure and material, but it is always related to the single-unit resonance frequency of the speaker.

[0049] For step S200, the acoustic mass of the sound guide tube 320 refers to the mass of the medium gas that is accelerated through the sound guide tube 320 under static force but without significant compression. Acoustic mass is a type of acoustic impedance, which refers to the complex ratio of the pressure of the medium on a certain area of ​​the wavefront to the volume velocity passing through this area. Generally, in acoustic analysis, the characteristic impedance of air is used to represent the acoustic impedance. Acoustic impedance is a complex number with a real part and an imaginary part, which can be compared with electrical impedance. Applying this analogy, the real part of the acoustic impedance is called acoustic resistance, and the imaginary part is called acoustic reactance. Therefore, the circuit theory method can be used to analyze acoustic problems. At this time, the sound pressure is usually regarded as an analogy of voltage, and the volume velocity is regarded as an analogy of current. In this way, the various parts of the acoustic circuit can directly establish an analogy relationship with the electrical quantities corresponding to them. Acoustic resistance is related to the energy loss caused by the viscous motion of the medium gas in the pipeline, so the acoustic resistance is analogous to the resistance. Acoustic mass is the mass of the part of the medium gas that is accelerated and displaced under static force but without significant compression. Acoustic mass acts as an inductor. Acoustic compliance is related to the volume of the dielectric gas that is statically compressed without significant average displacement of its center of gravity, and acts as a capacitor. Acoustic mass and acoustic compliance are both acoustic reactances, analogous to inductance and capacitance, respectively.

[0050] For step S300, when the sound frequency is below the low-frequency resonance frequency, the acoustic compliance of the front cavity of the earphone is proportional to the cavity volume. Usually, the volume of the front cavity of the earphone is very small, and at this time, the acoustic resistance of the front cavity of the earphone is very large, which can be approximated to an open circuit state in electricity, and can filter out more sound. The acoustic impedance of the sound outlet of the front cavity of the earphone is proportional to the sound frequency, and the sound quality of the sound outlet is inversely proportional to its area. Usually, the area of ​​the sound outlet of the front cavity of the earphone is relatively large, so the acoustic impedance of the sound outlet is very small at low frequencies, which is approximated to a short circuit state in electricity, and can better conduct sound. The sound quality of the sound guide tube 320 is inversely proportional to the low-frequency resonance frequency. Therefore, the greater the sound quality of the sound guide tube 320, the lower the low-frequency resonance frequency, and the lower the cutoff frequency of the low-frequency noise.

[0051] Some embodiments, see Figure 5 , the steps of obtaining the sound quality of the sound guide tube 320 are specifically as follows:

[0052] S210, obtaining the radius of the sound outlet hole, the center distance of the sound outlet hole, the length of the sound outlet hole, and the number of the sound outlet holes;

[0053] S220, obtaining sound quality according to the radius of the sound outlet hole, the center distance of the sound outlet hole, the length of the sound outlet hole, and the number of sound outlet holes.

[0054] For step S210, in this embodiment, the sound outlet hole is a circular hole. The center distance of the sound outlet hole is the distance between the centers of two adjacent holes, and the length of the sound outlet hole is related to the thickness of the earphone housing 500. In an exemplary embodiment, the sound outlet hole can also be a square hole.

[0055] For step S220, if the radius a of the sound outlet satisfies Wherein f represents the sound frequency passing through the sound outlet hole. When the number of the sound outlet hole is one, the sound quality calculation formula of the sound guide tube 320 is:

[0056]

[0057] In formula (1), M d is the sound quality of the sound guide tube 320, ρ is the air density, L is the length of the birth hole, and a is the radius of the sound outlet hole.

[0058] When there are multiple birth holes, the sound quality calculation formula of the sound guide tube 320 is:

[0059]

[0060] In formula (2), M d is the sound mass of the sound guide tube 320, ρ is the air density, L is the length of the sound hole, a is the radius of the sound hole, N is the number of the sound holes, b is the center distance of the sound holes and b>2a.

[0061] Some embodiments, see Figure 6 , the steps of obtaining the low-frequency resonance frequency of the earphone low-frequency noise according to the monomer resonance frequency and the sound quality are specifically as follows:

[0062] S310, obtaining the acoustic compliance of the vent hole, the acoustic compliance of the earmuff, the acoustic compliance of the speaker, and the equivalent vibration area of ​​the diaphragm of the earphone;

[0063] S320, obtaining a low-frequency resonance frequency according to the monomer resonance frequency, the sound quality, the acoustic compliance of the vent hole, the acoustic compliance of the earmuff, the acoustic compliance of the speaker, and the equivalent vibration area.

[0064] For step S310 and step S320, the calculation formula of the low-frequency resonance frequency is:

[0065]

[0066] In formula (3), f lis the low-frequency resonance frequency of the earphone after the speaker is installed in the earphone, f g is the single resonance frequency of the speaker, M d is the sound quality of the sound guide tube 320, C ah For the vent sound compliance, C ar For earmuffs, C m is the acoustic compliance of the speaker, and S is the equivalent vibration area of ​​the speaker diaphragm. It should be noted that the acoustic compliance of the vent hole refers to the equivalent acoustic compliance from the vent hole to the back cavity of the earphone.

[0067] For specific examples, see Figure 7 After using the earmuffs provided with the sound guide tube 320, the sound waves with a frequency below 100 Hz will be significantly weakened by the earphones, and the lower the sound wave frequency, the stronger the weakening effect. Usually, the frequency of the audio that users need to listen to when using earphones is much greater than 100 Hz, so setting the sound guide tube 320 to filter out low-frequency noise will hardly affect the listening effect.

[0068] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments" or "specific examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. Low frequency noise reduction method, It is characterized in that The invention is applied to low-frequency noise reduction headphones, and the low-frequency noise reduction headphones include: low-frequency noise reduction earmuffs, and the low-frequency noise reduction earmuffs include: earmuff leather, and the earmuff leather is used to fit the ear of the user; earmuff sponge, and the earmuff sponge is arranged on the lower side of the earmuff leather, and the earmuff sponge is used to support the earmuff leather; an earmuff bracket, and the earmuff bracket is arranged on the lower side of the earmuff sponge, and the earmuff bracket is provided with a sound guide cavity, and the earmuff bracket is provided with at least one sound guide tube, and the sound guide tube is a conducting cavity connected to the sound guide cavity and passes through the earmuff bracket, and the sound guide tube is provided by setting the guide tube. The sound tube filters out low-frequency sound waves that generate low-frequency oscillation noise; an earphone shell, the earphone shell is connected to the earmuff bracket of the low-frequency noise reduction earmuff, the earphone shell is provided with a sound outlet and a vent, the sound outlet is located at the connection between the earphone shell and the low-frequency noise reduction earmuff; a speaker, the speaker is accommodated in the earphone shell, the speaker includes a diaphragm, and the diaphragm is used to vibrate and sound; a noise reduction module, the noise reduction module is accommodated in the earphone shell, the noise reduction module is connected to the speaker, and the noise reduction module is used to eliminate noise, the method includes: Get the single-unit resonance frequency of the speaker; Obtain the sound quality of the sound guide tube; Obtaining a low-frequency resonance frequency of the earphone low-frequency noise according to the monomer resonance frequency and the sound quality; The step of obtaining the sound quality of the sound guide tube specifically includes: Obtain the radius of the sound hole, the center distance of the sound hole, the length of the sound hole and the number of the sound holes; the center distance of the sound hole is the distance between the centers of two adjacent holes; The sound quality is obtained according to the sound hole radius, the sound hole center distance, the sound hole length and the number of sound holes. If the radius of the sound hole satisfy , f represents the sound frequency passing through the sound outlet. When the number of the sound outlet is one, the calculation formula of the sound quality is: in, is the sound quality, is the air density, is the length of the sound outlet; When there are multiple sound outlets, the sound quality calculation formula is: in, is the number of sound holes, b is the center distance of the sound holes, and b>2a; The step of obtaining the low-frequency resonance frequency of the earphone low-frequency noise according to the monomer resonance frequency and the sound quality specifically includes: Obtain the acoustic compliance of the vent hole, the acoustic compliance of the earmuff, the acoustic compliance of the speaker, and the equivalent vibration area of ​​the diaphragm of the earphone, wherein the acoustic compliance of the vent hole refers to the equivalent acoustic compliance from the vent hole to the rear cavity of the earphone; The low-frequency resonance frequency is obtained according to the monomer resonance frequency, the sound mass, the air vent compliance, the earmuff compliance, the speaker compliance and the equivalent vibration area, and the calculation formula of the low-frequency resonance frequency is: in, is the low frequency resonance frequency, is the monomer resonance frequency, For the air vent sound compliance, For the earmuff sound compliance, is the acoustic compliance of the speaker, and S is the equivalent vibration area.

2. The low-frequency noise reduction method according to claim 1, It is characterized in that The earmuff leather is provided with a receiving groove, and the receiving groove is used to receive the earmuff sponge.

3. The low-frequency noise reduction method according to claim 2, It is characterized in that The earmuff sponge is annular, and the containing groove is an annular groove.

4. The low-frequency noise reduction method according to claim 1, It is characterized in that One end of the sound guide tube close to the sound guide cavity is provided with a mesh cloth groove, and the mesh cloth groove is used for installing the sound guide mesh cloth.

5. The low-frequency noise reduction method according to claim 1, It is characterized in that The earmuff sponge is made of memory sponge.

6. The low-frequency noise reduction method according to claim 1, It is characterized in that The earmuff bracket is provided with four sound guide tubes, and the four sound guide tubes are distributed symmetrically in the center.

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