Sound system for seat and seat with built-in speaker

Abstract

The present invention addresses the problem of providing a sound system for a seat and a seat with a built-in speaker that make it difficult for others to listen to sound to be listened. [Solution] In addition to four loudspeakers (141) (SLI1, SLI2, SRI1, SRI2) that emit sounds from the left and right sides of the head toward the inside of a seat (100) with built-in loudspeakers, four loudspeakers (141) (SLE1, SLE2, SRE1, SRE2) that emit sounds from the left and right sides of the head toward the outside of the seat (100) with built-in loudspeakers are provided. The sound field control filter processes the sound to be listened output to each speaker (141). Sound pressure and sound pressure gradient (sound pressure gradient) are as zero as possible at boundary (BS1) of peripheral area (A1) of user seated in seat (100) with built-in speaker, and sound to be listened reaches audiovisual area (A2) around head of user seated in seat (100) with built-in speaker when sound to be listened has natural sound pressure suitable for listening to sound to be listened and in the internal mode, the sound field is controlled.

Description

Technical Field

[0001] This invention relates to a technique for suppressing sound leakage from a speaker output to the surrounding environment in a seat with a built-in speaker. Background Technology

[0002] In seats with built-in speakers, a known technique for suppressing sound leakage from the speakers to the surroundings is as follows: In an audio device having a shape that surrounds the left and right rear sides of the head of a user sitting in the seat, a speaker that emits sound from the left side of the head toward the inside of the seat, a speaker that emits sound from the right side of the head toward the inside of the seat, and a soundproofing component surrounding the left and right rear sides of the user are provided, and the soundproofing component suppresses sound leakage from the speakers to the outside (for example, Patent Document 1).

[0003] In addition, as a technology related to the present invention, the following boundary sound field control technology is known: based on the Kirchhoff-Helmholtz integral equation, the interference sound field at the boundary of the user's area based on the sound of each speaker becomes a sound field with a sound pressure level of 0 for the target sound, and the target sound is output from multiple speakers, thereby minimizing the magnitude of the target sound propagating outside the area (e.g., Patent Document 2, Patent Document 3).

[0004] Existing technical documents:

[0005] Patent documents:

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-103862

[0007] Patent Document 2: Japanese Patent Application Publication No. 2006-74442

[0008] Patent Document 3: Japanese Patent Application Publication No. 2008-252625 Summary of the Invention

[0009] The problem that the invention aims to solve:

[0010] According to the technology described above, which uses a sound device with a shape that surrounds the left and right rear of the head of a user sitting in a seat, sound leakage in the forward direction cannot be suppressed because sound insulation is not performed on the front side of the user.

[0011] Furthermore, it is impossible to suppress sound leakage caused by diffraction in the left, right, and rear directions. Even if this were not the case, it is impossible to expect sufficient suppression of sound leakage by sound insulation components alone when the speaker volume is high.

[0012] Therefore, it is considered to apply the aforementioned boundary sound field control technique in this audio device to suppress sound leakage to areas outside the seat.

[0013] However, when multiple speakers are arranged in a sound device with a shape that surrounds the left and right rear of the user's head and emits sound from the left and right sides of the head toward the inside of the seat, the sound from the speakers that are mainly responsible for eliminating leakage sound arrives only as a low sound pressure caused by diffraction waves at positions further to the left and right rear of the seat. Therefore, at the boundaries of the area, it is not possible to control the sound field in a way that makes the sound pressure and sound pressure gradient approximately zero, which easily leads to the phenomenon that leakage to the outside of the area cannot be adequately suppressed.

[0014] In addition, the length of the audio device in the front-to-back direction needs to be limited to minimize the obstruction of the user's forward field of vision. Therefore, it is not possible to increase the distance between the speakers on the left and right sides. As a result, for the bass range, it is not possible to ensure sufficient phase difference between the speakers at the boundaries of the area. Consequently, it is not possible to control the sound field at the boundaries of the area in a way that makes the sound pressure and sound pressure gradient well zero, and sometimes it is not possible to sufficiently suppress leakage to the outside of the area.

[0015] Therefore, the objective of this invention is to more appropriately suppress the leakage of sound output from the speaker to the surrounding environment in a seat with a built-in speaker.

[0016] Methods used to solve problems:

[0017] To achieve the aforementioned objectives, the present invention provides a sound system for a seat, applicable to a seat having a support member disposed to the side of the head of a seated user, comprising: an inward-facing speaker supported on the support member in a left-right direction of the seat, configured to emit sound toward the inside of the seat; an outward-facing speaker supported on the support member in the left-right direction, configured to emit sound toward the outside of the seat; and a sound field control unit that processes the target sound in a manner that partially reproduces the target sound within a defined area around the seat, and outputs the target sound to the inward-facing speaker and the outward-facing speaker, wherein the target sound is the sound that the user is listening to.

[0018] Furthermore, to achieve the aforementioned objectives, the present invention provides a sound system for a seat, which is applied to a seat having a left support member disposed to the left of the head of a seated user and a right support member disposed to the right of the head. The sound system for the seat comprises: n or more (wherein n≥1) left-facing inward speakers, configured to emit sound toward the inside of the seat in the left-right direction, supported on the left support member; m or more (wherein m≥1) left-facing outward speakers, configured to emit sound toward the outside of the seat in the left-right direction, supported on the left support member; and p or more (wherein p≥1) left-facing outward speakers. A right inward-facing speaker, configured to emit sound toward the inside of the seat in the left-right direction, is supported on the right support member; q or more (where q≥1) right outward-facing speakers, configured to emit sound toward the outside of the seat in the left-right direction, are supported on the right support member; and a sound field control unit, which processes the listening object sound in such a way that it partially reproduces the listening object sound inside a defined area around the seat, and outputs it to the left inward-facing speaker, the left outward-facing speaker, the right inward-facing speaker, and the right outward-facing speaker, wherein the listening object sound is the sound of the object being listened to by the user.

[0019] Here, the seat audio system can also be configured such that the sound field control unit convolves the target sound with a signal obtained by converting the signal into the transfer function corresponding to each of the left inward-facing speaker, the left outward-facing speaker, the right inward-facing speaker, and the right outward-facing speaker, respectively, and outputs each signal as an output signal to a speaker corresponding to the transfer function convolved in the output signal. The transfer function corresponding to each speaker is set such that the sound pressure level and sound pressure gradient of the target sound are as close to zero as possible at the boundaries of the region.

[0020] In addition, in this case, it is preferable that the transfer function corresponding to each of the speakers is set such that the target sound can be heard well in the area around the head of the person sitting in the seat.

[0021] In addition, the present invention also provides a speaker-integrated seat, a seat audio system having the seat and above, wherein the sound field control unit is integrated into the seat.

[0022] According to the above-described seat audio system, the seat with built-in speakers, in addition to four speakers that emit sound from the side of the head toward the inside of the seat, there are also speakers that emit sound from the side toward the outside of the seat. Therefore, even at positions further to the side and rear of the seat, the speaker that emits sound from the outside can deliver the speaker sound responsible for eliminating leakage sound as a direct sound to these positions. As a result, leakage of the listening object sound from the surrounding area of ​​the seat can be suppressed more appropriately.

[0023] Invention effects:

[0024] As described above, according to the present invention, in a seat with a built-in speaker, it is possible to more appropriately suppress the leakage of sound output from the speaker to the surroundings. Attached Figure Description

[0025] Figure 1 This is a block diagram illustrating the structure of a seat audio system according to an embodiment of the present invention.

[0026] Figure 2 This is a diagram illustrating the configuration of the loudspeakers according to an embodiment of the present invention.

[0027] Figure 3 This diagram illustrates an example of the boundaries when controlling sound pressure and sound pressure gradient using a seat audio system according to an embodiment of the present invention.

[0028] Figure 4 This is a diagram showing the structure of the seat audio system according to an embodiment of the present invention when the filter coefficients are set.

[0029] Figure 5 This diagram illustrates the configuration of the audio sensors when the filter coefficients of the seat audio system according to an embodiment of the present invention are set.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1… Seat audio system, 2… Audio source, 3… Audio sensor, 4… Filter characteristic setting unit, 11… Audio receiver, 12… Sound field control processing unit, 13… Amplifier group, 14… Speaker group, 100… Speaker built into the seat, 101… Left ear outer panel, 102… Right ear outer panel, 121… Sound field control filter, 131… Amplifier, 141… Speaker. Detailed Implementation

[0032] The embodiments of the present invention will be described below.

[0033] Figure 1 This describes the structure of the seat audio system in this embodiment.

[0034] This seat audio system is a system built into a seat with built-in speakers, i.e., a speaker-in-seat system. It is a system that controls the sound field in a way that allows the user sitting in the speaker-in-seat to hear the specified target sound well, while making it difficult for others outside the area around the speaker-in-seat to hear it.

[0035] As shown in the figure, the seat audio system 1 includes an audio receiver 11, a sound field control and processing unit 12, an amplifier group 13, and a speaker group 14.

[0036] The speaker group 14 has eight speakers 141: SLI1, SLI2, SRI1, SRI2, SLE1, SLE2, SRE1, and SRE2.

[0037] The amplifier group 13 includes eight amplifiers 131 corresponding to the speakers 141, and the sound field control processing unit 12 includes eight sound field control filters 121 corresponding to the speakers 141.

[0038] The audio receiver 11 receives the reproduced sound of the audio content from the audio source 2 that reproduces the audio content via wireless communication or the like as the listening target sound, and outputs it to each sound field control filter 121.

[0039] Each sound field control filter 121 is, for example, an FIR filter, and each sound field control filter 121 has filter coefficients (transfer characteristics) preset for performing specified sound field control. Each sound field control filter 121 convolves the target sound input from the audio receiver 11 based on the transfer characteristics of the preset filter coefficients, and outputs the filtered target sound as the target sound to the corresponding speaker 141 via the same amplifier 131. Each amplifier 131 amplifies the filtered target sound input from the sound field control filter 121 and outputs it to the corresponding speaker 141.

[0040] here, Figure 2 This indicates the configuration of the eight speakers 141: SLI1, SLI2, SRI1, SRI2, SLE1, SLE2, SRE1, and SRE2.

[0041] Figure 2 'a' represents the right side view of the speaker-built seat 100. Figure 2 The 'b' indicates the front view. Figure 2 The 'c' represents the left side view. Figure 2 The 'd' indicates the back view. Figure 2 The 'e' represents the diagram above. Figure 2 f is a magnification representation Figure 2 A portion of the diagram of e.

[0042] As shown in the figure, the speaker-in-seat 100 has a left ear plate 101 extending forward from the left side of the headrest to the left side of the head of the user sitting in the speaker-in-seat 100, and a right ear plate 102 extending forward from the right side of the headrest to the right side of the head of the user sitting in the speaker-in-seat 100, as components for supporting each speaker 141.

[0043] Furthermore, among the eight speakers 141, SLI1 and SLI2 are arranged in a front-to-back direction on the right side of the left ear outer panel 101 (inner side of the seat) and emit sound towards the right side (inner side of the seat); SRI1 and SRI2 are arranged in a front-to-back direction on the left side of the right ear outer panel 102 (inner side of the seat) and emit sound towards the left side (inner side of the seat); SRE1 and SRE2 are arranged in a front-to-back direction on the left side of the left ear outer panel 101 (outer side of the seat) and emit sound towards the left side (outer side of the seat); and SRE1 and SRE2 are arranged in a front-to-back direction on the right side of the right ear outer panel 102 (outer side of the seat) and emit sound towards the right side (outer side of the seat).

[0044] Next, Figure 3 Examples of sound field control of the listening object sound implemented by the various sound field control filters 121 are shown in a and b.

[0045] As in Figure 3 Figure a shows the view from the side. Figure 3 As shown in diagram b, which is viewed from above, the sound field control implemented by each sound field control filter 121 is performed in such a way that the sound pressure and sound pressure gradient (sound pressure tilt) of the target sound are minimized to zero at the boundary BS1 of the peripheral region A1 of the user seated in the speaker-built seat 100. By performing this boundary sound field control, the leakage of the target sound to the outside of the boundary BS1 is minimized, and the target sound is locally reproduced in the peripheral region A1. In addition, setting the sound pressure gradient (sound pressure tilt) to 0 is equivalent to setting the particle velocity to 0.

[0046] Furthermore, the sound field control implemented by each sound field control filter 121 is performed in such a way that the sound of the listening object reaches the audiovisual area A2 around the head of the user sitting in the speaker-built seat 100 with a natural sound pressure level suitable for listening to the sound of the listening object.

[0047] Furthermore, the audiovisual area A2 becomes part of the surrounding area A1. Additionally, the surrounding area A1 is, for example, defined as the area within 1m to 1.5m of the user seated in the speaker-integrated seat 100.

[0048] With such sound field control, the user seated in the speaker-in-speaker seat 100 can hear the target sound well and minimize the target sound that leaks out of the user's surrounding area A1.

[0049] In this embodiment, in addition to the four speakers SLI1, SLI2, SRI1, and SRI2 that emit sound from the left and right sides of the head toward the inside of the speaker-built seat 100, four other speakers SLE1, SLE2, SRE1, and SRE2 that are respectively arranged on the left and right sides and emit sound toward the outside of the speaker-built seat 100 are also provided as speakers for sound field control as described above.

[0050] Therefore, even in a position further to the left or right rear of the seat, the speaker sound responsible for eliminating leakage can be delivered directly from the four speakers 141 (SLE1, SLE2, SRE1, SRE2) that emit sound outwards to that position. As a result, leakage of the listening target sound from the surrounding area A1 of the speaker-built seat 100 can be more appropriately suppressed.

[0051] Here, the settings of each sound field control filter 121 can be configured. Figure 4 This is done beforehand in the structure shown.

[0052] As shown in the figure, this structure becomes... Figure 1 The seat audio system 1 shown is a structure consisting of multiple audio sensors 3, such as a microphone, microphone array, sound pressure sensor, and sound pressure gradient sensor, and a filter characteristic setting unit 4.

[0053] As in Figure 5 Figure a shows the view from the side. Figure 5 As shown in diagram b, which is viewed from above, the sound sensors 3 are respectively arranged at multiple locations (control points) on the boundary BS1 of the peripheral area A1, and at standard locations (control points) for the left and right ears of the user seated in the speaker-integrated seat 100.

[0054] Then, based on the target sound and the output of each audio sensor 3, the transfer function from each speaker 141 to each control point is calculated. Based on the calculated transfer function, the filter coefficients of the sound field control filter 121, which aims to achieve the desired response at each control point, are calculated and set for each sound field control filter 121. Here, the desired response at the control point is a response where the sound pressure and sound pressure gradient (sound pressure tilt) are zero at multiple locations on the boundary BS1, i.e., the control points. Regarding the control points, which are the standard positions of the left and right ears of the seated user, the desired response at the control point is essentially a response where the sound volume follows the target sound. Here, the response where the sound volume follows the target sound also includes sound that imparts acoustic characteristics to the target sound that enhance the user's listening experience.

[0055] The embodiments of the present invention have been described above.

[0056] In addition, the parts of the seat audio system 1 in the above embodiments, other than the speaker group 14, can also be located outside the speaker-in-seat 100.

[0057] Furthermore, in the above description, two speakers 141 are respectively arranged on the inner and outer sides of the left ear outer plate 101 and the inner and outer sides of the right ear outer plate 102. However, the number of speakers 141 arranged on each part can be arbitrary, and the number of speakers on each part can also be different.

Claims

1. A sound system for a seat applied to a seat provided with a support member configured to the side of a head of a user seated, characterized by, has: an inward-facing speaker supported by the support member in a left-right direction of the seat in a configuration that emits sound toward an inner side of the seat; an outward-facing speaker supported by the support member in the left-right direction in a configuration that emits sound toward an outer side of the seat; and a sound field control unit that, after signal processing the sound to be heard by the user as an object of hearing in a manner that causes the sound to be heard to be reproduced locally on an inner side of a prescribed region around the seat, outputs the sound to the inward-facing speaker and the outward-facing speaker. The seat audio system has:

2. A sound system for a seat, applied to a seat provided with a left support member arranged at a left side of a head of a user seated and a right support member arranged at a right side of the head, characterized by comprising: a left speaker arranged in the left support member; a right speaker arranged in the right support member; and a control unit configured to control the left speaker and the right speaker, wherein the control unit is configured to control the left speaker and the right speaker so that a sound output from the left speaker and a sound output from the right speaker are different from each other. n or more left inward-facing speakers supported by the left support member in a left-right direction of the seat in a configuration that emits sound toward an inner side of the seat, where n ≥ 1; m or more left outward-facing speakers supported by the left support member in the left-right direction in a configuration that emits sound toward an outer side of the seat, where m ≥ 1; p or more right inward-facing speakers supported by the right support member in the left-right direction of the seat in a configuration that emits sound toward an inner side of the seat, where p ≥ 1; q or more right outward-facing speakers supported by the right support member in the left-right direction in a configuration that emits sound toward an outer side of the seat, where q ≥ 1; and a sound field control unit that, after signal processing the sound to be heard by the user as an object of hearing in a manner that causes the sound to be heard to be reproduced locally on an inner side of a prescribed region around the seat, outputs the sound to the left inward-facing speakers, the left outward-facing speakers, the right inward-facing speakers, and the right outward-facing speakers.

3. The seat audio system according to claim 2, wherein the sound field control unit convolves the sound to be heard with a transfer function respectively corresponding to each of the left inward-facing speakers, the left outward-facing speakers, the right inward-facing speakers, and the right outward-facing speakers, which is set so that a sound pressure and a sound pressure gradient of the sound to be heard are as close to 0 as possible at a boundary of the region, and outputs the resulting signals as output signals to the speakers corresponding to the transfer functions convolved into the output signals.

4. The seat audio system according to claim 3, wherein the transfer function respectively corresponding to each of the speakers is set so that the sound to be heard can be heard and seen well in a region around a head of a person seated on the seat.

5. A speaker-embedded seat, comprising: the seat and the seat audio system according to any one of claims 1 to 4, the sound field control unit is embedded in the seat. ​

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