Headrest having independent sound zone

Abstract

Provided in the present invention is a headrest having an independent sound zone, the headrest comprising a headrest body and an acoustic radiation system, wherein the acoustic radiation system comprises an acoustic transducer and an acoustic dipole, which are fixed to the headrest body and are arranged independently of each other, the acoustic transducer is used for radiating sound to a designated area, the acoustic dipole comprises a first housing fixed to the headrest body, and a first sound production unit and a second sound production unit, which are fixed in the first housing and are spaced apart opposite each other, the first sound production unit and the second sound production unit each radiate sound in at least two directions, and there is a phase difference between the sound radiated by the first sound production unit and the sound radiated by the second sound production unit. In the present invention, the acoustic transducer and the acoustic dipole cooperate with each other, such that vector superposition can be performed on the sound in a target area other than a designated area, and a sound pressure level difference between the designated area and the target area is maximized, and thus the sound leakage of a headrest speaker is reduced, thereby achieving a relatively good sound zoning or sound isolation effect and improving the user experience.

Description

A type of headrest with independent vocal registers Technical Field

[0001] This invention belongs to the field of automotive parts technology, and in particular relates to an independent sound zone headrest. Background Technology

[0002] Currently, the level and scope of intelligence in car cockpits are increasing, and the audio system, as an important component of in-vehicle entertainment systems, is also gaining importance among consumers. Among these features, headrest speakers are increasingly being equipped in various models. These not only provide better near-field surround sound, but also offer a degree of independent navigation, calling, and voice interaction, especially for the driver's seat passenger. It can be said that headrest speakers are gradually becoming a standard feature in intelligent cockpits.

[0003] In related technologies, one of the original design goals of headrest speakers is to provide passengers with a relatively independent and private sound zone. However, traditional design solutions cannot achieve good sound zoning or sound isolation effects, resulting in a poor user experience.

[0004] Therefore, it is necessary to provide a new headrest with independent vocal registers. Technical issues

[0005] The purpose of this invention is to provide an independent sound zone headrest that can solve the technical problem of poor privacy in vehicle headrests in related technologies. Technical solutions

[0006] The technical solution of the present invention is as follows:

[0007] An independent sound zone headrest includes a headrest body and an acoustic radiation system housed within the headrest body. The acoustic radiation system includes an acoustic transducer and an acoustic dipole fixed to the headrest body and independently disposed therefrom. The acoustic transducer is used to radiate sound to a designated area. The acoustic dipole includes a first outer shell fixed to the headrest body, and a first sound-emitting unit and a second sound-emitting unit fixed within the first outer shell and distributed at relative intervals. Both the first sound-emitting unit and the second sound-emitting unit radiate sound in at least two directions, and the sound radiated by the first sound-emitting unit and the second sound-emitting unit have a phase difference.

[0008] Optionally, the first sound-emitting unit, the second sound-emitting unit, and the first outer shell together enclose a first rear cavity.

[0009] Both the first sound-generating unit and the second sound-generating unit are sound-generating devices, and the vibrations of the first sound-generating unit and the second sound-generating unit have a phase difference; or,

[0010] One of the first sound-generating unit and the second sound-generating unit is a sound-generating device, and the other is a passive radiating diaphragm.

[0011] The first sound-emitting unit and the first outer shell together form a second rear cavity, and the second sound-emitting unit and the first outer shell together form a third rear cavity. The second rear cavity and the third rear cavity are not connected to each other.

[0012] The acoustic transducer includes a second outer shell fixed to the headrest body and a third sound-emitting unit fixed inside the second outer shell. The third sound-emitting unit is used to radiate sound to a designated area.

[0013] The third sound-emitting unit is provided, and the third sound-emitting unit and the second outer shell together form a fourth rear cavity; or...

[0014] The third sound-emitting unit is provided in multiple units, and the multiple third sound-emitting units together with the second outer shell form a fourth rear cavity; or...

[0015] The third sound-emitting unit is provided in multiple ways, and the multiple third sound-emitting units together with the second shell form multiple fourth rear cavities, which are not interconnected.

[0016] The third sound-emitting unit is provided in multiple units, and the multiple third sound-emitting units are distributed in an array.

[0017] The array shape of the third sound-emitting unit includes any one of the following: long strip, circle, or rectangle.

[0018] The acoustic transducer is provided by one unit, and the acoustic dipoles are provided by two units, with the acoustic transducer positioned between the two acoustic dipoles; or...

[0019] The acoustic transducer is provided in two parts, and the acoustic dipole is provided in one part, with the acoustic dipole located between the two acoustic transducers.

[0020] The headrest body is provided with a first sound outlet, a second sound outlet and a third sound outlet. The first sound outlet is located on the sound-emitting side of the acoustic transducer, the second sound outlet is located on the sound-emitting side of the first sound-emitting unit, and the third sound outlet is located on the sound-emitting side of the second sound-emitting unit. Beneficial effects

[0021] The beneficial effects of this invention are as follows: the acoustic transducer can radiate sound to a designated area, thereby enabling sound to be reproduced within that area; the first and second sound-emitting units of the acoustic dipole radiate sound in at least two directions, allowing the acoustic dipole to radiate sound to a target area outside the designated area. When the directional radiation effect of the acoustic transducer to the designated area is poor, the first and second sound-emitting units can radiate sound to the target area outside the designated area, thereby enabling vector superposition of the sound from the target area outside the designated area, maximizing the sound pressure level difference between the designated area and the target area, reducing sound leakage from the headrest speaker, and thus achieving better sound zoning or sound isolation effects, improving the user experience. Attached Figure Description

[0022] Figure 1 is a schematic diagram of the independent sound zone headrest provided by the present invention installed in the driver's seat of a car;

[0023] Figure 2 is a left view of the independent sound zone headrest provided in an embodiment of the present invention, which is provided with an acoustic transducer and two acoustic dipoles.

[0024] Figure 3 is a cross-sectional view along direction AA in Figure 2;

[0025] Figure 4 is a left view of the independent sound zone headrest provided in the embodiment of the present invention when it is equipped with two acoustic transducers and one acoustic dipole.

[0026] Figure 5 is a cross-sectional view along the BB direction in Figure 4;

[0027] Figure 6 is a schematic diagram of the acoustic dipole structure of the independent vocal range headrest provided in an embodiment of the present invention;

[0028] Figure 7 is a cross-sectional view along the CC direction when the first and second sound generating units in Figure 6 are sound generating devices and share the same rear cavity;

[0029] Figure 8 is a cross-sectional view along the CC direction when the first sound-generating unit in Figure 6 is a sound-generating device, the second sound-generating unit is a passive radiating diaphragm, and they share the same rear cavity.

[0030] Figure 9 is a cross-sectional view along the CC direction when the first and second sound generating units in Figure 6 are sound generating devices and use independent rear cavities;

[0031] Figure 10 is a structural schematic diagram of the acoustic transducer of the independent sound zone headrest provided in an embodiment of the present invention when it is equipped with three third sound-emitting units;

[0032] Figure 11 is a cross-sectional view along the DD direction when the three third sound-producing units in Figure 10 share the same rear cavity;

[0033] Figure 12 is a cross-sectional view along the DD direction when the three third sound-emitting units in Figure 10 use independent rear cavities;

[0034] Figure 13 is a schematic diagram showing the sound radiated by the first sound-generating unit of the acoustic dipole to different locations inside the vehicle.

[0035] Figure 14 is a schematic diagram showing the second sound-emitting unit of the acoustic dipole radiating sound to different locations inside the vehicle. Embodiments of the present invention

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Referring to Figure 1, the independent sound zone headrest 10 provided by this invention can be applied to the seats of a car 20, and the independent sound zone headrest 10 can be installed in the driver's seat. The independent sound zone headrest 10 can radiate sound to a designated area, or it can radiate sound to a target area outside the designated area; wherein, in a specific example, the designated area is the driver's seat, and the target area is the passenger seat, the left rear seat, and the right rear seat, etc.

[0038] Please refer to Figures 2 to 12. The present invention provides an independent sound zone headrest 10, including a headrest body 1 and a sound radiation system 2 housed within the headrest body 1. The sound radiation system 2 includes an acoustic transducer 21 fixed to the headrest body 1 and independently arranged with each other, and an acoustic dipole 22. The acoustic transducer 21 is used to radiate sound to a designated area. The acoustic dipole 22 includes a first outer shell 221 fixed to the headrest body 1, and a first sound-emitting unit 222 and a second sound-emitting unit 223 fixed within the first outer shell 221 and relatively spaced apart. The first sound-emitting unit 222 and the second sound-emitting unit 223 both radiate sound in at least two directions, and the sound radiated by the first sound-emitting unit 222 and the second sound-emitting unit 223 have a phase difference.

[0039] The acoustic transducer 21 can radiate sound to a designated area, thereby enabling sound to be reproduced within that area. The first sound-emitting unit 222 and the second sound-emitting unit 223 of the acoustic dipole 22 both radiate sound in at least two directions, allowing the acoustic dipole 22 to radiate sound to a target area outside the designated area. When the directional radiation effect of the acoustic transducer 21 to the designated area is poor, the first sound-emitting unit 222 and the second sound-emitting unit 223 can radiate sound to the target area outside the designated area. This allows for vector superposition of the sound from the target area outside the designated area, maximizing the sound pressure level difference between the designated area and the target area, reducing sound leakage from the headrest speaker, and thus achieving better sound zoning or sound isolation effects, improving the user experience.

[0040] It should be noted that the acoustic transducer 21 is used to control the directionality of sound, enabling directional sound radiation of the acoustic transducer 21 to the target area. The directional control effect of the acoustic transducer 21 is related to the frequency of the sound; the higher the frequency, the better the directional control effect and the more concentrated the sound energy radiation; the lower the frequency, the worse the directional control effect and the more diffuse the sound energy radiation. When the acoustic transducer 21 cannot achieve a good directional sound radiation effect through directional control, an acoustic dipole 22 is used to perform vector superposition control on the sound radiated to the target area outside the designated area. This maximizes the sound pressure level difference between different areas, thereby achieving full-frequency domain sound reproduction in the designated area and reducing sound leakage from the headrest speakers.

[0041] Please refer to Figures 6 to 9. In this embodiment of the invention, the acoustic dipole 22 may include one first sound-emitting unit 222 and one second sound-emitting unit 223, or it may include multiple first sound-emitting units 222 and multiple second sound-emitting units 223. The first sound-emitting unit 222 and the second sound-emitting unit 223 are arranged facing each other and are relatively close. The phase difference between the sound radiated by the first sound-emitting unit 222 and the second sound-emitting unit 223 may be due to a certain difference in the vibration phase of the sound-emitting device itself, for example, the input signals input to the first sound-emitting unit 222 and the second sound-emitting unit 223 may have a certain phase difference or delay; or it may be a passive implementation method using physical structure design, for example, setting an anisotropic front cavity, a rear cavity phase inverter, a passive radiating diaphragm, an acoustic waveguide, etc. The first sound-emitting unit 222 and the second sound-emitting unit 223 may share the same rear cavity, or they may use independent rear cavities.

[0042] Please refer to Figures 7 and 8. In some embodiments, the first sound-emitting unit 222, the second sound-emitting unit 223, and the first housing 221 together enclose the first rear cavity 2211, that is, the first sound-emitting unit 222 and the second sound-emitting unit 223 share the same rear cavity, and the structure of the acoustic dipole 22 is relatively simple. The first sound-emitting unit 222 and the second sound-emitting unit 223 can be sound-emitting devices, such as dynamic loudspeakers, electrostatic loudspeakers, MEMS loudspeakers, or loudspeaker modules.

[0043] The following example illustrates how the sound radiated by the first sound unit 222 and the second sound unit 223 has a phase difference:

[0044] Please refer to Figure 7. In a specific example, the phase difference in the sound radiated by the first sound unit 222 and the second sound unit 223 may be due to a certain difference in the vibration phase of the sound-emitting devices themselves. For example, since both the first sound unit 222 and the second sound unit 223 are sound-emitting devices, the input signals input to the first sound unit 222 and the second sound unit 223 have a certain phase difference or delay, which causes the vibration of the first sound unit 222 and the second sound unit 223 to have a phase difference.

[0045] Referring to Figure 8, in a specific example, the phase difference between the sounds radiated by the first sound-emitting unit 222 and the second sound-emitting unit 223 can be achieved passively through physical structural design. For example, one of the first sound-emitting unit 222 and the second sound-emitting unit 223 can be a sound-emitting device, and the other can be a passive radiating diaphragm. Specifically, the first sound-emitting unit 222 can be a sound-emitting device, and the second sound-emitting unit 223 can be a passive radiating diaphragm. The sound-emitting device and the passive radiating diaphragm share the same rear cavity, and the passive radiating diaphragm cannot actively emit sound. When the first sound-emitting unit 222 vibrates, the air compression force through the first rear cavity 2211 causes the second sound-emitting unit 223 to passively vibrate and radiate sound outwards simultaneously. This physical structural design allows the sounds radiated outwards by the first sound-emitting unit 222 and the second sound-emitting unit 223 to be out of phase.

[0046] Referring to Figure 9, in some embodiments, the first sound-emitting unit 222 and the first housing 221 together enclose a second rear cavity 2212, and the second sound-emitting unit 223 and the first housing 221 together enclose a third rear cavity 2213. The second rear cavity 2212 and the third rear cavity 2213 are not connected to each other, that is, the first sound-emitting unit 222 and the second sound-emitting unit 223 use independent rear cavities. The vibration characteristics of the first sound-emitting unit 222 and the second sound-emitting unit 223 will not interfere with each other. Moreover, the vibration phase of the first sound-emitting unit 222 and the second sound-emitting unit 223 can be controlled separately, which is beneficial for accurately adjusting the phase difference of the sound radiated outward by the first sound-emitting unit 222 and the second sound-emitting unit 223. The first sound-emitting unit 222 and the second sound-emitting unit 223 can be sound-emitting devices, such as dynamic loudspeakers, electrostatic loudspeakers, MEMS loudspeakers, or loudspeaker modules.

[0047] It should be noted that, regardless of whether the acoustic dipole 22 uses an independent rear cavity or shares the same rear cavity, the first front cavity 2221 of the acoustic dipole 22 can be formed by the first sound-emitting unit 222 and the first outer shell 221 together, as shown in Figures 3 and 5, or it can be formed by the first sound-emitting unit 222, the first outer shell 221 and the headrest body 1 together; the second front cavity 2231 of the acoustic dipole 22 can be formed by the second sound-emitting unit 223 and the first outer shell 221 together, as shown in Figures 3 and 5, or it can be formed by the second sound-emitting unit 223, the first outer shell 221 and the headrest body 1 together.

[0048] Please refer to Figures 10, 11, and 12. The acoustic transducer 21 includes a second housing 211 fixed to the headrest body 1 and a third sound-emitting unit 212 fixed within the second housing 211. The third sound-emitting unit 212 is used to radiate sound to a designated area. The third sound-emitting unit 212 can be a transducer that converts electrical signals into sound signals for radiation, such as a moving-coil loudspeaker, an electrostatic loudspeaker, a MEMS loudspeaker, or a loudspeaker module. One or more third sound-emitting units 212 can be provided. When the transducer itself has strong directional characteristics, only one third sound-emitting unit 212 can be provided. When the transducer itself has poor directional characteristics, multiple third sound-emitting units 212 can be used, and the multiple third sound-emitting units 212 can be arranged in an array. The array shape of the third sound-emitting units 212 includes any one of the following: elongated, circular, or rectangular.

[0049] The following example illustrates the configuration of the acoustic transducer 21:

[0050] In a specific example, the third sound-emitting unit 212 is provided, and the third sound-emitting unit 212 and the second outer shell 211 together form a fourth rear cavity 2111. At this time, the transducer of the third sound-emitting unit 212 has a strong directional characteristic.

[0051] Please refer to Figure 11. In a specific example, there are multiple third sound-emitting units 212. The multiple third sound-emitting units 212 and the second shell 211 together enclose the fourth rear cavity 2111, that is, the acoustic transducers 21 share the same rear cavity, which is simple in structure. For example, there are three third sound-emitting units 212. The three third sound-emitting units 212 and the second shell 211 together enclose the fourth rear cavity 2111, and the three third sound-emitting units 212 are in a long strip array.

[0052] Please refer to Figure 12. In a specific example, there are multiple third sound-emitting units 212. The multiple third sound-emitting units 212 and the second shell 211 together enclose multiple fourth rear cavities 2111. The multiple fourth rear cavities 2111 are not connected to each other. That is, the three third sound-emitting units 212 of the acoustic transducer 21 adopt independent rear cavities, and the vibration characteristics of the three third sound-emitting units 212 will not interfere with each other. For example, there are three third sound-emitting units 212. The three third sound-emitting units 212 and the second shell 211 together enclose three fourth rear cavities 2111. The three fourth rear cavities 2111 are not connected to each other, and the three third sound-emitting units 212 are in a long strip array.

[0053] It should be noted that, regardless of whether the acoustic transducer 21 uses an independent rear cavity or shares the same rear cavity, its rear cavity can be formed by the third sound-emitting unit 212 and the second outer shell 211, as shown in Figures 3 and 5, or it can be formed by the third sound-emitting unit 212, the second outer shell 211 and the headrest body 1 together. Moreover, the third front cavity 213 of the acoustic transducer 21 can be formed by the third sound-emitting unit 212 and the second outer shell 211, as shown in Figures 3 and 5, or it can be formed by the third sound-emitting unit 212, the second outer shell 211 and the headrest body 1 together. No specific restrictions are made here.

[0054] Please refer to Figures 2 to 5. In this embodiment of the invention, the arrangement of the acoustic transducer 21 and the acoustic dipole 22 on the headrest body 1 can be adjusted according to the actual design, for example:

[0055] Please refer to Figures 2 and 3. In a specific example, there is one acoustic transducer 21 and two acoustic dipoles 22, with the acoustic transducer 21 positioned between the two acoustic dipoles 22.

[0056] Please refer to Figures 4 and 5. In a specific example, there are two acoustic transducers 21 and one acoustic dipole 22, which is located between the two acoustic transducers 21.

[0057] Please refer to Figures 2 and 3. The headrest body 1 is provided with a first sound outlet 31, a second sound outlet 41, and a third sound outlet 51. The first sound outlet 31 is located on the sound-emitting side of the acoustic transducer 21, so that the acoustic transducer 21 can radiate sound outward through the first sound outlet 31. The second sound outlet 41 is located on the sound-emitting side of the first sound-emitting unit 222, so that the first sound-emitting unit 222 can radiate sound outward through the second sound outlet 41. The third sound outlet 51 is located on the sound-emitting side of the second sound-emitting unit 223, so that the second sound-emitting unit 223 can radiate sound outward through the third sound outlet 51. The sound-emitting sides of the first sound-emitting unit 222 and the second sound-emitting unit 223 are located on opposite sides of the headrest body 1.

[0058] As shown in Figures 2 to 5, the surface of the headrest body 1 is provided with a first mesh cover 3, a second mesh cover 4, and a third mesh cover 5, according to actual needs. The first mesh cover 3 is located on the sound-emitting side of the acoustic transducer 21, and the first sound outlet 31 is located on the first mesh cover 3; the second mesh cover 4 is located on the sound-emitting side of the first sound-emitting unit 222, and the second sound outlet 41 is located on the second mesh cover 4; the third mesh cover 5 is located on the sound-emitting side of the second sound-emitting unit 223, and the third sound outlet 51 is located on the third mesh cover 5.

[0059] It should be understood that the acoustic transducer 21 is used for directional sound control, so that the sound emitted by the acoustic transducer 21 is directionally radiated to the user in the driver's seat. The sound radiation characteristics after directional control of the acoustic transducer 21 in the xy plane are explained below. The sound radiation energy is minimal in the x-axis direction, moderate in the direction between the x and y axes, and maximum in the y-axis direction. Since the user is located in the y-axis direction of the independent sound zone headrest 10, directional control of the acoustic transducer 21 concentrates its radiated sound primarily in the y-axis direction, achieving directional sound radiation and thus enabling sound reproduction in a designated area.

[0060] The acoustic dipole 22 can radiate sound to the driver's seat, the front passenger seat, the left rear seat, and the right rear seat, as shown in Figure 13. Figure 13 is a schematic diagram of the first sound-emitting unit 222 of the acoustic dipole 22 in the independent sound zone headrest 10 radiating sound to different positions inside the vehicle. Taking the acoustic dipole 22 located on the left side as an example, the sound-emitting side of its first sound-emitting unit 222 faces the inside of the independent sound zone headrest 10, and the sound radiated by the sound-emitting side of the first sound-emitting unit 222 to the four positions inside the vehicle are respectively... The sound at time t can then be represented in the following form:

[0061] Where A1 represents the sound intensity emitted by the sound-emitting side of acoustic dipole 22; φ1 represents the sound propagation distance from the sound-emitting side of the acoustic dipole 22 to the driver's seat, passenger seat, left rear seat, and right rear seat in the vehicle, respectively; ω represents the angular frequency of the radiated sound; k represents the wave number of the radiated sound, k = ω / c, where c represents the speed of sound; φ1 represents the initial phase of the sound radiated outward by the first sound-emitting unit 222 in the left acoustic dipole 22; e represents the natural constant; and j represents the imaginary number.

[0062] Continuing with the example of the acoustic dipole 22 located on the left, as shown in Figure 14, Figure 14 is a schematic diagram of the sound radiated by the second sound-emitting unit 223 of the acoustic dipole 22 in the independent sound zone headrest 10 to different positions inside the vehicle. The sound-emitting side of the second sound-emitting unit 223 faces the outer side of the independent sound zone headrest 10. Due to the obstruction of the independent sound zone headrest 10, the sound emitted by the second sound-emitting unit 223 to the driver's position is much smaller than the sound emitted by the first sound-emitting unit 222 to the driver's position. Furthermore, the driver's position is very close to the sound-emitting side of the first sound-emitting unit 222. Therefore, the sound at the driver's position is mainly affected by the sound radiated by the first sound-emitting unit 222. Thus, the sound radiated by the second sound-emitting unit 223 to each position inside the vehicle is... Then, the sound at a certain moment can be represented in the following form:

[0063] Wherein, A2 represents the sound intensity emitted from the sound-emitting side of the second sound-emitting unit 223; φ1 represents the sound propagation distance from the sound-emitting side of the second sound-emitting unit 223 to the passenger seat, the left rear seat, and the right rear seat; φ2 represents the initial phase of the sound radiated outward by the second sound-emitting unit 223 in the left acoustic dipole 22.

[0064] It should be understood that by controlling different sound signals fed to the first sound-producing unit 222 and the second sound-producing unit 223 of the left acoustic dipole 22, A1, A2, φ1, and φ2 can be controlled, so that... The optimal solution that satisfies normal listening needs while meeting the following conditions:

[0065] Where | represents the modulus value calculation, it should be understood that when the optimal solution that meets the conditions of the above example is met, the sound in the full frequency domain can be reproduced in the driver's seat, and the sound leakage to the passenger seat, the left rear seat and the right rear seat can be reduced.

[0066] It should be noted that the sound radiation principle of the acoustic dipole 22 on the right is the same as that of the acoustic dipole 22 on the left, and will not be repeated here.

[0067] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A headrest with independent sound zones, comprising a headrest body and an acoustic radiation system housed within the headrest body, the acoustic radiation system comprising an acoustic transducer and an acoustic dipole fixed to the headrest body and independently disposed thereof, the acoustic transducer being used to radiate sound to a designated area, characterized in that, The acoustic dipole includes a first outer shell fixed to the headrest body, and a first sound-emitting unit and a second sound-emitting unit fixed inside the first outer shell and distributed relatively at intervals. The first sound-emitting unit and the second sound-emitting unit radiate sound in at least two directions, and the sound radiated by the first sound-emitting unit and the second sound-emitting unit have a phase difference.

2. The independent vocal range headrest according to claim 1, characterized in that, The first sound-emitting unit, the second sound-emitting unit, and the first outer shell together form the first rear cavity.

3. The independent vocal range headrest according to claim 2, characterized in that, Both the first sound-generating unit and the second sound-generating unit are sound-generating devices, and the vibrations of the first sound-generating unit and the second sound-generating unit have a phase difference; or, One of the first sound-generating unit and the second sound-generating unit is a sound-generating device, and the other is a passive radiating diaphragm.

4. The independent vocal range headrest according to claim 1, characterized in that, The first sound-emitting unit and the first outer shell together form a second rear cavity, and the second sound-emitting unit and the first outer shell together form a third rear cavity. The second rear cavity and the third rear cavity are not connected to each other.

5. The independent vocal range headrest according to claim 1, characterized in that, The acoustic transducer includes a second outer shell fixed to the headrest body and a third sound-emitting unit fixed inside the second outer shell. The third sound-emitting unit is used to radiate sound to a designated area.

6. The independent vocal range headrest according to claim 5, characterized in that, The third sound-emitting unit is provided, and the third sound-emitting unit and the second outer shell together form a fourth rear cavity; or... The third sound-emitting unit is provided in multiple units, and the multiple third sound-emitting units together with the second outer shell form a fourth rear cavity; or... The third sound-emitting unit is provided in multiple ways, and the multiple third sound-emitting units together with the second shell form multiple fourth rear cavities, which are not interconnected.

7. The independent vocal range headrest according to claim 5, characterized in that, The third sound-emitting unit is provided in multiple units, and the multiple third sound-emitting units are distributed in an array.

8. The independent vocal range headrest according to claim 7, characterized in that, The array shape of the third sound-emitting unit includes any one of the following: long strip, circle, or rectangle.

9. The independent vocal range headrest according to claim 1, characterized in that, The acoustic transducer is provided by one unit, and the acoustic dipoles are provided by two units, with the acoustic transducer positioned between the two acoustic dipoles; or... The acoustic transducer is provided in two parts, and the acoustic dipole is provided in one part, with the acoustic dipole located between the two acoustic transducers.

10. The independent vocal range headrest according to claim 1, characterized in that, The headrest body is provided with a first sound outlet, a second sound outlet and a third sound outlet. The first sound outlet is located on the sound-emitting side of the acoustic transducer, the second sound outlet is located on the sound-emitting side of the first sound-emitting unit, and the third sound outlet is located on the sound-emitting side of the second sound-emitting unit.

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