An acoustic amplification device applied to headphones

Abstract

This application mainly relates to a sound amplification device applied to headphones, including a box body, and a contact area for contacting the speaker of the headphones is provided on the box body, so that the vibration generated by the speaker can be transmitted to the box body through the contact area. Through the sound amplification device, this application can increase the contact area between the speaker of the headphones and the air, so as to amplify the mechanical vibration of the headphones through the box body, at least increasing the volume of the sound heard by the user and improving the sound quality.

Description

Technical Field

[0001] This application relates to the technical field of acoustic devices, and specifically relates to a sound amplification device applied to headphones. Background Art

[0002] Bone conduction is a sound conduction method, that is, converting an electrical signal into mechanical vibration, and realizing the transmission of sound waves through the human skull, bony labyrinth, inner ear lymph, spiral organ, auditory nerve, and auditory center of the cerebral cortex. Bone conduction headphones use bone conduction technology to transmit sound signals to users. Sound waves can directly pass through human tissues and bones to the auditory nerve without passing through the external auditory canal and eardrum, which can "liberate" both ears. Summary of the Invention

[0003] An embodiment of this application provides a sound amplification device applied to headphones. Among them, the sound amplification device includes a box body, and a contact area for contacting the speaker of the headphones is provided on the box body, so that the vibration generated by the speaker can be transmitted to the box body through the contact area.

[0004] The beneficial effect of this application is that the sound amplification device provided by this application can be applied to headphones. By the sound amplification device, the contact area between the speaker of the headphones and the air can be increased, so as to amplify the mechanical vibration of the headphones through the box body, at least increasing the volume of the sound heard by the user and improving the sound quality. Brief Description of the Drawings

[0005] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0006] Figure 1 is a schematic structural diagram of an embodiment of the headphones described in this application;

[0007] Figure 2 is a schematic diagram of the principle of air vibration caused by mechanical vibration described in this application;

[0008] Figure 3 is a schematic structural diagram of an embodiment of the sound amplification device provided by this application;

[0009] Figure 4 is Figure 3 the schematic acoustic principle diagram of the sound amplification device in ;

[0010] Figure 5 is Figure 3 the schematic structural diagram of an embodiment of the contact area in ;

[0011] Figure 6 is Figure 5 the frequency response curve corresponding to the contact surface formed between the middle contact area and the skin contact area of the speaker;

[0012] Figure 7 is a schematic structural diagram of another embodiment of the sound amplification device provided by the present application;

[0013] Figure 8 is Figure 7 the schematic diagram of the acoustic principle of the sound amplification device in

[0014] Figure 9 is a schematic structural diagram of yet another embodiment of the sound amplification device provided by the present application;

[0015] Figure 10 is Figure 9 the schematic diagram of the acoustic principle of the sound amplification device in

[0016] Figure 11 is the frequency response curve of the sound amplification device provided by the present application;

[0017] Figure 12 is a schematic structural diagram of still another embodiment of the sound amplification device provided by the present application. Specific embodiments

[0018] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only partial embodiments of the present application rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0019] When "embodiment" is mentioned in the present application, it means that the specific features, structures or characteristics described in combination with the embodiment may be included in at least one embodiment of the present application. Those skilled in the art understand explicitly and implicitly that the embodiments described in the present application may be combined with other embodiments.

[0020] For headphones, the mechanical vibrations generated by their speakers can be mainly transmitted through media such as air, and can also be mainly transmitted through media such as the user's skull. Among them, the former is generally called an air conduction headphone, and the latter is generally called a bone conduction headphone. In addition, since both air conduction headphones and bone conduction headphones have mechanical vibrations, those skilled in the art of this technology can easily think of applying the technical solutions of the present application to air conduction headphones and bone conduction headphones respectively, which will not be elaborated here. Based on this, the present application mainly takes bone conduction headphones as an example for exemplary illustration.

[0021] Refer jointly to Figure 1 andFigure 2 , Figure 1 is a schematic structural diagram of an embodiment of the earphone described in this application, Figure 2 and Figure 1 is a schematic diagram of the circuit structure of the earphone in

[0022] As Figure 1 shown, the earphone 10 may include two speakers 11, two earhook components 12, and a rear hook component 13. Among them, one end of each earhook component 12 is respectively connected to a corresponding speaker 11, and both ends of the rear hook component 13 are respectively connected to the other ends of the two earhook components 12 away from the speakers 11. In other words, the number of speakers 11 may be two, and the rear hook component 13 may be respectively connected to the two speakers 11 through the earhook components 12. Further, both earhook components 12 may be curved to facilitate hanging on the two ears of the user; the rear hook component 13 may also be curved to facilitate winding around the back of the user's head, thereby realizing the use requirement of the user wearing the earphone 10. With such a setting, when the earphone 10 is in a worn state, the two speakers 11 are respectively located on the left and right sides of the user's head; and under the combined action of the two earhook components 12 and the rear hook component 13, the two speakers 11 can clamp the user's head and contact the user's skin, thereby enabling the earphone 10 to transmit sound based on the technology.

[0023] It should be noted that: Figure 1 is only a schematic diagram of the morphological structure of a common bone conduction earphone. Those skilled in the art of this technology can easily know that by using an appropriate method and a sound amplification device to closely cooperate with other forms of earphones, mechanical vibrations can also be amplified, so as to achieve the effect of a passive speaker, and the form of the earphone has no restrictive effect.

[0024] The inventor of this application found in the long-term product R & D process that when the user wears the earphone 10, the unilateral pressing force exerted by the earphone 10 (specifically, the speaker 11) on the user's head can be within the range of 0.3N to 0.4N. At this time, both the comfort of the user wearing the earphone 10 and the acoustic performance of the earphone 10 (such as sound quality, volume, etc.) can be well demonstrated. Further, in combination with Figure 1 , the skin contact area of the speaker 11 described in this application specifically refers to the area where the speaker 11 contacts the user's head skin when the user wears the earphone 10.

[0025] Further, the earphone 10 may also include a main board 14 and a battery 15. Among them, in combination with Figure 2, the main board 14 and the battery 15 can be electrically connected to the two speakers 11 through corresponding wiring structures (such as wires). At this time, the main board 14 can be used to control the sound production of the speakers 11 (mainly converting electrical signals into mechanical vibrations), and the battery 15 can be used to supply power to the earphone 10 (specifically, the two speakers 11). Of course, the earphone 10 described in this application may further include microphones, pickups and other types of microphones, and may further include functional devices such as USB sockets and control buttons. They can also be electrically connected to the main board 14 and the battery 15 through corresponding wiring structures to achieve corresponding functions. For example: the microphone can implement functions such as calls of the earphone 10, the pickup can implement functions such as noise reduction of the earphone 10, the USB socket can implement functions such as wired charging and data transmission of the earphone 10, and the control button can implement functions such as turning on and off and volume adjustment of the earphone 10.

[0026] It should be noted that: in combination with Figure 1 , the main board 14 and the battery 15 can be respectively arranged in the two earhook components 12. Such an arrangement can not only increase the capacity of the battery 15 to improve the battery life of the earphone 10, but also balance the weight of the earphone 10 to improve the wearing comfort of the earphone 10.

[0027] Referring to Figure 2 , Figure 2 is a schematic diagram of the principle of mechanical vibration causing air vibration described in this application. Among them, Figure 2 (a) in it is a schematic diagram of the principle of the earphone directly causing air vibration described in this application, Figure 2 (b) in it is a schematic diagram of the principle of the earphone causing air vibration through a sound amplification device described in this application.

[0028] Based on the above related descriptions, when the user wears the earphone 10, the user can hear sounds such as music and voice through the earphone 10. When the user takes off the earphone 10, in combination with Figure 2 , this application can also be used in cooperation with a sound amplification device 20 and the earphone 10. That is to say, the sound amplification device 20 described in this application can be applied to the earphone 10 described in this application to amplify the mechanical vibration of the earphone 10 through the sound amplification device 20, at least so that the volume of the sound heard by the user can be increased (that is, the external sound function is realized), and the sound quality can be improved (for example, the sound range becomes wider). In other words, when the earphone 10 is used in cooperation with the sound amplification device 20, the mechanical vibration generated by the speaker 11 can drive the sound amplification device 20 to vibrate together, and then the sound amplification device 20 drives the air to vibrate. At this time, since the contact area between the sound amplification device 20 and the air is relatively large, it is beneficial to drive more air to participate in the vibration, and thus it is beneficial to improve the volume, sound quality, etc. of the sound heard by the user.

[0029] Refer to together Figure 3 andFigure 4 , Figure 3 is a schematic structural diagram of an embodiment of the sound reinforcement device provided by the present application, Figure 4 and Figure 3 is a schematic diagram of the acoustic principle of the sound reinforcement device in

[0030] In this embodiment, the sound reinforcement device 20 may include a box body 21. Based on the above related description, the box body 21 may be in a plate-like structure, a horn-like structure, a cavity structure, etc. The above structures can all increase the contact area between the speaker 11 and the air, thereby improving the volume, sound quality, etc. of the sound heard by the user. Among them, in combination with Figure 3 , this application takes the box body 21 as a cavity structure as an example for exemplary description. Further, a contact area 211 for contacting the speaker 11 of the earphone 10 is provided on the box body 21, so that the vibration generated by the speaker 11 can be transmitted to the box body 21 through the contact area 211. At this time, the box body 21 further converts the above vibration into an air conduction vibration. In other words, the earphone 10 can contact the box body 21 through the contact area 211 provided on the box body 21, so that the mechanical vibration generated by the speaker 11 can drive the box body 21 to vibrate accordingly, and the vibration generated by the box body 21 is transmitted through the air as a medium, thereby forming the propagation of sound.

[0031] As an example, as Figure 3 shown, the box body 21 may include an outer box body 212. Among them, the outer box body 212 may be a structure with a cavity inside, such as a spherical shape or a cylindrical shape. It should be noted that: sharp protrusions and / or depressions should be avoided as much as possible on the inner wall of the outer box body 212 to optimize the acoustic performance of the box body 21. Further, the outer box body 212 can enclose and form a first chamber 2121. Among them, the structural parameters such as the volume and shape of the first chamber 2121 can adjust the acoustic performance of the box body 21. For example: the larger the volume of the first chamber 2121, the better the acoustic performance of the box body 21 in the low frequency band (for example, the frequency is less than 500 Hz); the more regular and round the shape of the first chamber 2121, the better the acoustic performance of the box body 21. At this time, the contact area 211 may be provided on the outer box body 212 so that the outer box body 212 vibrates synchronously with the speaker 11. In combination with Figure 4 , the frequency response curve of the box body 21 can form a peak or a trough.

[0032] In some embodiments, the first chamber 2121 can be a sealed space, that is, the medium (such as air) inside the first chamber 2121 is isolated from the external environment. At this time, during the synchronous vibration of the outer box 212 with the speaker 11, the medium inside the first chamber 2121 undergoes a large pressure change, which in turn reacts on the vibration of the outer box 212. In some other embodiments, the first chamber 2121 can be an open space, that is, the medium (such as air) inside the first chamber 2121 is in communication with the external environment. At this time, during the synchronous vibration of the outer box 212 with the speaker 11, the medium inside the first chamber 2121 undergoes a small pressure change, having a small impact on the vibration of the outer box 212. In other words, by setting the first chamber 2121 as a sealed space or an open space, the acoustic performance of the box 21 can also be adjusted.

[0033] The inventors of the present application found during the long-term product R & D process that: within a certain range, the greater the stiffness of the contact area 211, the smaller the deformation generated when the structure is stressed, which is also beneficial to the transmission of mechanical vibration. However, if the stiffness of the contact area 211 is too large, during the synchronous vibration of the outer box 212 with the speaker 11, the contact area 211 is prone to relative movement with the skin contact area of the speaker 11, thereby reducing the transmission effect of mechanical vibration and even colliding with the speaker 11 to produce abnormal noise. In this regard, in this embodiment, the elastic modulus of the contact area 211 is set to be less than the elastic modulus of other areas of the outer box 212. In other words, the outer box 212 can be softer in the contact area 211 to ensure the efficiency of the speaker 11 transmitting mechanical vibration to the outer box 212 and avoid abnormal noise. Exemplarily, the elastic modulus of the contact area 211 can be 1 - 3 GPa, and the elastic modulus of other areas of the outer box 212 is 6 - 8 GPa. Based on this, the outer box 212 can adopt a two-color injection molding process. The material of the outer box 212 in the contact area 211 can be polycarbonate, polyamide, acrylonitrile-butadiene-styrene copolymer, etc., and the material of the outer box 212 in other areas can be a mixture of polycarbonate, polyamide, acrylonitrile-butadiene-styrene copolymer, etc. and glass fiber or carbon fiber (for example, adding 20% - 50% of glass fiber to polycarbonate).

[0034] Further, in combination with Figure 1, based on the basic structure of the earphone 10, the number of contact areas 211 can be two, and the two contact areas 211 are symmetrically arranged on opposite sides of the outer box body 212. Such a setting allows the rear hanging component 13 (and the ear hanging component 12) of the earphone 10 to straddle the outer box body 212, and press and fix the two speakers 11 on the corresponding contact areas 211 respectively. In other words, the outer box body 212 is equivalent to the user's head, and the earphone 10 clamping the outer box body 212 can simply be regarded as the user wearing the earphone 10. Therefore, based on the above related description, the pressing force of the speaker 11 on the corresponding contact area 211 can be 0.3 - 0.4N.

[0035] It should be noted that: the contact area 211 can be set in a concave shape, that is, the contact area 211 can have a certain depth to accommodate the speaker 11, thereby increasing the accuracy and reliability of the earphone 10 clamping the outer box body 212. Based on this, the specific position of the contact area 211 on the outer box body 212 can be reasonably designed according to the acoustic performance of the outer box body 212, and no limitation is made here. Further, since the contact area 211 can be set in a concave shape, after the specific position of the contact area 211 on the outer box body 212 is reasonably designed according to the acoustic performance of the outer box body 212, it is determined, and the earphone 10 can be clamped at the same position on the outer box body 212 each time, thereby increasing the consistency in acoustic performance when the outer box body 212 cooperates with the earphone 10.

[0036] Refer jointly to Figure 5 and Figure 6 , Figure 5 is Figure 3 a schematic structural diagram of an embodiment of the contact area in Figure 6 is Figure 5 the frequency response curve corresponding to the contact surface formed between the contact area in

[0037] As Figure 5 shown, the outer box body 212 can also be provided with a plurality of protruding portions 2122 distributed at intervals in the contact area 211. The protruding portions 2122 can mainly be used to adjust the size of the contact surface formed between the contact area 211 of the outer box body 212 and the skin contact area of the speaker 11 (in short, adjust the size of the contact surface formed between the speaker 11 and the outer box body 212), thereby adjusting to a certain extent the strength of the mechanical vibration of the speaker 11 transmitted to the outer box body 212. Specifically, when the two speakers 11 are respectively pressed and fixed on the corresponding contact areas 211, combined with Figure 5, the skin contact area of the speaker 11 (which can be defined as the "vibration surface") contacts the protrusions 2122. Obviously, the more the number of the protrusions 2122, the larger the area of the surface where each protrusion 2122 contacts the speaker 11, and the larger the contact surface formed between the speaker 11 and the outer box 212; correspondingly, the larger the proportion of the contact surface to the vibration surface.

[0038] During the long-term product R & D process, the inventors of this application found that: as Figure 6 shown, for different proportions of the contact surface to the vibration surface, the overall trend of the frequency response curve is generally the same, which indicates that the size of the contact surface formed between the outer box 212 in the contact area 211 and the skin contact area of the speaker 11 has little effect on the sound quality. Further, as the proportion of the contact surface to the vibration surface gradually increases, the frequency response curve tends to a greater vibration intensity, that is, the corresponding volume is larger. Preferably, the proportion of the contact surface to the vibration surface is not less than 50%, that is, the contact surface formed between the contact area 211 and the skin contact area of the speaker 11 is not less than 50% of the area of the skin contact area of the speaker 11. It should be noted that: for the low-frequency band below 400 Hz, the difference in volume between the case where the proportion of the contact surface to the vibration surface is 25% and the case where the proportion is 100% is about 12 dB, which indicates that the coincidence of the contact surface and the vibration surface is beneficial to maximizing the volume.

[0039] It should be noted that: arranging the protrusions 2122 in the contact area 211 can adjust the size of the contact surface formed between the speaker 11 and the outer box 212, and arranging depressions (structurally opposite to the protrusions 2122) in the contact area 211 can also adjust the size of the contact surface formed between the speaker 11 and the outer box 212. Further, whether it is the protrusions 2122 or the depressions, they can all be an integrally formed structure with the contact area 211.

[0040] Refer jointly to Figures 7 to 10 , Figure 7 is a schematic structural diagram of another embodiment of the sound amplification device provided by this application, Figure 8 is Figure 7 the schematic diagram of the acoustic principle of the sound amplification device in Figure 9 is a schematic structural diagram of yet another embodiment of the sound amplification device provided by this application, Figure 10 is Figure 9 the schematic diagram of the acoustic principle of the sound amplification device in

[0041] The main difference from the above embodiment is that: in this embodiment, as Figure 7 or Figure 9As shown, the box 21 may further include an inner box 213. The inner box 213 is disposed in the first chamber 2121 and may be surrounded to form a second chamber 2131. In this way, the inner box 213 may be mainly used to form resonance with the outer box 212, so as to increase the bandwidth (that is, the frequency band width) of the box 21 and optimize the sound quality of the box 21. In other words, Figure 3 The box 21 shown can be simply regarded as a single-cavity structure, which can achieve the effect of amplifying the sound of a narrow frequency band; Figure 7 or Figure 9 The box 21 shown can be simply regarded as a double-cavity structure, which is easier to achieve a wider frequency band sound amplification effect than a single-cavity structure. Theoretically, the more cavities the box 21 has, the easier it is to achieve a wider frequency band sound amplification effect, and the more conducive to optimizing sound quality.

[0042] It should be noted that: Figure 7 , Figure 9 and Figure 3 , since the inner box body 213 can be disposed in the outer box body 212, the second chamber 2131 can be simply regarded as a part of the first chamber 2121. In other words, combined with Figure 7 , Figure 9 The first chamber 2121 is divided into two relatively independent spaces by the inner box body 213 , one of the spaces being the second chamber 2131 .

[0043] Similarly, the inner box 213 may be in a spherical or columnar structure. Further, the inner box 213 avoids sharp protrusions and / or depressions as much as possible to optimize the acoustic performance of the box 21 .

[0044] In some embodiments, in combination Figure 7 , the second chamber 2131 can be a closed space, that is, the medium (such as air) in the second chamber 2131 is isolated from the external environment. At this time, when the box 21 vibrates synchronously with the speaker 11, the medium in the first chamber 2121 and the medium in the second chamber 2131 will undergo a large pressure change, which will then react to the vibration of the outer box 212 and the inner box 213, that is, it will have a greater impact on the vibration of the box 21. At this time, combined with Figure 8 , the box body 21 can be divided into three parts; accordingly, the box body 21 can form three peaks or troughs.

[0045] In some other embodiments, in combination Figure 9, the second chamber 2131 can be an open space, that is, the medium (such as air) inside the second chamber 2131 communicates with the external environment. At this time, during the synchronous vibration of the box body 21 with the speaker 11, the medium in the first chamber 2121 undergoes a relatively large pressure change, while the medium in the second chamber 2131 undergoes a relatively small pressure change, which also reacts on the vibration of the outer box body 212 and the inner box body 213, that is, has a greater impact on the vibration of the box body 21. At this time, combined with Figure 10 , the box body 21 can be split into two parts; correspondingly, the box body 21 can form two peaks or troughs.

[0046] Refer to Figure 11 , Figure 11 is the frequency response curve of the sound reinforcement device provided by this application. It should be noted that: Figure 11 The described sound reinforcement device can correspond to Figure 7 or Figure 9 the double-chamber structure shown. Among them, for the convenience of research, both cavities corresponding to the double-chamber structure are based on the sphere model, that is, the outer box body 212 (and the first chamber 2121 formed by it) and the inner box body 213 (and the second chamber 2131 formed by it) are both spheres. Based on this, according to the volume calculation formula of the sphere, the ratio between the volume of the second chamber 2131 and the volume of the first chamber 2121 can be converted into the ratio between the radius of the second chamber 2131 and the radius of the first chamber 2121 (abbreviated as "the ratio of the inner and outer cavity radii"). Of course, in some other embodiments, the above cavities can also be regular structures such as ellipsoids, cylinders, prisms, etc., or other irregular structures. In this regard, those skilled in the art can also obtain similar test results.

[0047] The inventor of this application found during the long-term product R & D process that: as Figure 11 shown, for different ratios between the volume of the second chamber 2131 and the volume of the first chamber 2121, the larger the ratio of the volume of the second chamber 2131 to the volume of the first chamber 2121, the higher the frequency corresponding to the resonance peak in the low-frequency band (such as the frequency less than 500 Hz) and the lower the corresponding intensity, which indicates that the performance of the bass is greatly affected by the ratio of the inner and outer cavity radii. Preferably, the ratio between the volume of the second chamber 2131 and the volume of the first chamber 2121 can be within the range of 1:10 to 1:3. Further, the frequency response curves almost coincide in the 200 - 2500 Hz frequency band, which indicates that the performance of the midrange is less affected by the ratio of the inner and outer cavity radii.

[0048] Refer to Figure 12 , Figure 12 is the structural schematic diagram of another embodiment of the sound reinforcement device provided by this application.

[0049] The main difference from any of the above embodiments is that in this embodiment, as Figure 12 shown, the sound amplification device 20 may further include a first wireless charging module 22 disposed on the outer box body 212. Among them, the first wireless charging module 22 may be based on wireless charging protocols such as Qi standard, PMA standard, A4WP standard, etc. At this time, the first wireless charging module 22 is configured to be able to wirelessly charge the earphone 10 through the second wireless charging module of the earphone 10. Correspondingly, the second wireless charging module may be based on wireless charging protocols such as Qi standard, PMA standard, A4WP standard, etc. Further, the sound amplification device 20 may further include a first wireless communication module 23 and a control module 24 disposed on the outer box body 212. Among them, the first wireless communication module 23 may be based on wireless communication technologies such as Bluetooth, ZigBee, NFC, etc., and the control module 24 may be based on physical buttons exposed on the outer box body 212. At this time, the control module 24 is configured to be able to send a control signal to the earphone 10 through the wireless communication connection between the first wireless communication module 23 and the second wireless communication module of the earphone 10. Correspondingly, the second wireless communication module may be based on wireless communication technologies such as Bluetooth, ZigBee, NFC, etc., and may be integrated on the main board 14. In other words, when the sound amplification device 20 is used in cooperation with the earphone 10, it can not only realize the function of external sound through the cooperation between the box body 21 and the speaker 11, but also realize the wireless charging function through the cooperation between the first wireless charging module 22 and the second wireless charging module, and can also establish a wireless communication connection through the first wireless communication module 23 and the second wireless communication to realize functions such as music playing and voice call control.

[0050] It should be noted that: in addition to being able to wirelessly charge the earphone 10, the first wireless charging module 22 can also wirelessly charge electronic devices such as mobile phones and wireless earphones. Further, the sound amplification device 20 may further be provided with a fast charging module ( Figure 12 not shown in the figure) for fast charging of electronic devices such as mobile phones and tablet computers. Among them, corresponding interfaces such as type-C interfaces are provided on the sound amplification device 20.

[0051] As an example, in combination with Figure 12 , the first wireless charging module 22 may be independent of the outer box body 212. For example, the sound amplification device 20 is additionally provided with a base 25, the base 25 is connected to the outer box body 212, and the first wireless charging module 22, the first wireless communication module 23 and the above-mentioned fast charging module may all be disposed in the base 25. Such a setting can avoid a greater impact on the acoustic performance of the box body 21 after the sound amplification device 20 integrates too many functional modules.

[0052] As an example, in combination with Figure 12, multifunctional buttons, volume up buttons, and volume down buttons may be exposed on the outer box body 212 to control the earphone 10 to implement operations such as playing, pausing, song switching, and volume adjustment. Among them, pressing the multifunctional button once briefly can implement the play and pause functions, and pressing it twice quickly and continuously can implement the song switching function; pressing the volume up button briefly can implement the volume increase function, and pressing it long can implement the continuous and rapid volume increase function; pressing the volume down button briefly can implement the volume decrease function, and pressing it long can implement the rapid volume decrease function.

[0053] The above are only some embodiments of the present application, and thus do not limit the protection scope of the present application. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. An acoustic amplification device applied to headphones, characterized in that, The earphone is an air conduction earphone or a bone conduction earphone. The earphone includes two speakers and a rear hanger assembly connecting the two speakers. The sound amplification device includes a box body. The contact area between the box body and the air is larger than the contact area between the speaker and the air. The box body includes an outer box body which encloses and forms a first chamber. The outer box body is provided with two contact areas for respectively contacting the two speakers. The two contact areas are symmetrically arranged on opposite sides of the outer box body to allow the rear hanger assembly to be straddled on the outer box body and press and fix the two speakers on the corresponding contact areas respectively, so that the vibration generated by the speakers can be transmitted to the box body through the contact areas. The pressing force of the speaker on the corresponding contact area and the unilateral pressing force on the user's head when the earphone is worn on the user's head are both 0.3 - 0.4N. The box body further converts the vibration generated by the speakers into air conduction vibration.

2. The sound reinforcement device according to claim 1, wherein The box body further includes an inner box body which is arranged in the first chamber and encloses and forms a second chamber. The inner box body is used to resonate with the outer box body.

3. The sound reinforcement device according to claim 2, characterized in that, The ratio of the volume of the second chamber to the volume of the first chamber is within the range of 1:10 to 1:

3.

4. The sound reinforcement device according to claim 1, characterized in that, The contact area is arranged in a concave shape to accommodate the speaker.

5. The sound reinforcement device according to claim 1, characterized in that, The elastic modulus of the contact area is set to be less than the elastic modulus of other areas of the outer box body.

6. The sound reinforcement device according to claim 5, wherein The elastic modulus of the contact area is 1 - 3GPa, and the elastic modulus of other areas of the outer box body is 6 - 8GPa.

7. The sound reinforcement device according to claim 1, wherein, The contact surface formed between the contact area and the skin contact area of the speaker is not less than 50% of the area of the skin contact area of the speaker.

8. The public address device according to claim 1, characterized in that, The sound amplification device further includes a first wireless charging module arranged on the outer box body.

9. The sound reinforcement device according to claim 1, characterized in that The sound amplification device further includes a first wireless communication module and a control module arranged on the outer box body.

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