Acoustic system, method for controlling an acoustic system, and method for manufacturing an acoustic system

Abstract

To keep sound propagation within the intended range. [Solution] The acoustic system 100 comprises a vibrating member 110, one or more sound generating devices 121 that generate sound directed toward the vibrating member 110 based on an acoustic signal, one or more vibrators 122 attached to the vibrating member 110 and that vibrate the vibrating member 110, a first signal output device 131 that outputs a first acoustic signal to the sound generating device 121, and a second signal output device 132 that outputs a second acoustic signal to the vibrator 122, which is a corrected version of the first acoustic signal that suppresses sound propagation in a non-propagation region 202 that is outside the region where sound emitted from the sound generating device 121 and passed through the vibrating member 110 is intended to propagate.

Description

Technical Field

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[0001] The present disclosure relates to an acoustic system that limits the sound propagation area, an acoustic system control method, and an acoustic system manufacturing method.

Background Art

[0002] Patent Document 1 describes an acoustic system that prevents sound emitted from speakers other than a predetermined speaker from reaching a person sitting near the predetermined speaker in a situation where different sounds are emitted from a plurality of speakers arranged at different positions, such as in an airplane cabin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is room for improvement in the acoustic system described in Patent Document 1.

[0005] The present disclosure provides an acoustic system, an acoustic system control method, and an acoustic system manufacturing method that enable further improvement.

Means for Solving the Problems

[0006] One of the acoustic systems disclosed herein comprises: a vibrating member; one or more sound generating devices that generate sound directed toward the vibrating member based on an acoustic signal; one or more vibrators attached to the vibrating member and that vibrate the vibrating member; a first signal output device that outputs a first acoustic signal to the sound generating device; and a second signal output device that outputs a second acoustic signal to the vibrator, which is a corrected version of the first acoustic signal that suppresses the propagation of sound in a non-propagation region that is outside the region where sound emitted from the sound generating device 121 and passed through the vibrating member is intended to propagate.

[0007] One of the methods for controlling an acoustic system, as disclosed herein, comprises: a vibrating member; one or more sound generating devices that generate sound directed toward the vibrating member based on an acoustic signal; one or more vibrators attached to the vibrating member and that vibrate the vibrating member; a first signal output device that outputs a first acoustic signal to the sound generating device; and a second signal output device that outputs a second acoustic signal to the vibrator, which is a corrected version of the first acoustic signal that suppresses the propagation of sound in a non-propagation region that is outside the region intended to propagate the sound emitted from the vibrating member based on the first acoustic signal, wherein the second signal output device includes a correction filter that corrects the first acoustic signal and outputs it to the vibrator, and the correction filter controls the sound A method for controlling an acoustic system to set the filter characteristics of a correction filter in an acoustic system having filter characteristics derived based on the transmission characteristics of sound emitted by a sound generator and propagated through a vibrating member, wherein measuring devices are placed at one or more locations within the non-propagation region, and the filter characteristics of the correction filter are set based on a first sound signal measured by the measuring device of sound emitted from the sound generator and propagated through the vibrating member based on the first sound signal, and a first sound pressure transfer function between the first sound signal and the first sound signal, and a second sound pressure transfer function between the second sound signal and the second sound signal and the second sound signal.

[0008] One of the methods for manufacturing an acoustic system, as disclosed herein, comprises: a vibrating member; one or more sound generating devices that generate sound directed toward the vibrating member based on an acoustic signal; one or more vibrators attached to the vibrating member and that vibrate the vibrating member; a first signal output device that outputs a first acoustic signal to the sound generating device; and a second signal output device that outputs a second acoustic signal to the vibrator, which is a corrected version of the first acoustic signal that suppresses the propagation of sound in a non-propagation region that is outside the region intended to propagate the sound emitted from the vibrating member based on the first acoustic signal, wherein the second signal output device includes a correction filter that corrects the first acoustic signal and outputs it to the vibrator, and the correction filter is emitted by the sound generating device. A method for manufacturing an acoustic system, comprising setting the filter characteristics of a correction filter provided in an acoustic system having filter characteristics derived based on the transmission characteristics of sound propagated through the vibrating member, wherein measuring devices are placed at one or more locations within the non-propagation region, and the filter characteristics of the correction filter are set based on a first measurement signal, which is sound emitted from the vibrating member by the excitation force generated by the sound generating device based on the first acoustic signal, measured by the measuring device, and a first sound pressure transfer function between the first acoustic signal and the first acoustic signal, and a second measurement signal, which is sound emitted from the vibrating member by the excitation force generated by the vibrator based on the second acoustic signal, measured by the measuring device, and a second sound pressure transfer function between the second acoustic signal and the second acoustic signal. [Effects of the Invention]

[0009] Further improvements can be made according to the acoustic system, acoustic system control method, and acoustic system manufacturing method of this disclosure. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing the acoustic system. [Figure 2] Figure 2 is a perspective view showing the acoustic system with a portion of the enclosure omitted. [Figure 3] Figure 3 shows the functional configuration of the acoustic system. [Figure 4]Figure 4 shows the characterization system for the first measurement method. [Figure 5] Figure 5 shows the characterization system for the second measurement method. [Figure 6] Figure 6 shows the characterization system for the third measurement method. [Figure 7] Figure 7 is a perspective view showing another example of an acoustic system. [Figure 8] Figure 8 is a perspective view showing another example of the sound system (Example 2) with part of the enclosure omitted. [Modes for carrying out the invention]

[0011] The embodiments of the acoustic system, acoustic system control method, and acoustic system manufacturing method relating to this disclosure will be described below with reference to the drawings. The following embodiments are provided as examples to illustrate this disclosure and are not intended to limit it. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical formulas, the content of each step in the method, and the order of each step shown in the following embodiments are examples and may include content not described below. Geometric expressions such as parallel and orthogonal may be used, but these expressions do not indicate mathematical rigor and include substantially acceptable errors and deviations. Similarly, expressions such as simultaneous and identical also include substantially acceptable ranges.

[0012] Furthermore, the drawings are schematic diagrams that have been appropriately emphasized, omitted, or had their proportions adjusted to illustrate this disclosure, and do not represent the actual shapes, positions, or proportions.

[0013] Furthermore, in the following, multiple inventions may be described comprehensively as a single embodiment. Also, some of the content described below is described as an optional component relating to this disclosure.

[0014] Figure 1 is a perspective view showing the acoustic system 100. Figure 2 is a perspective view showing a portion of the housing 140 of the acoustic system 100 omitted. Figure 3 is a diagram showing the functional configuration of the acoustic system 100. The acoustic system 100 is a system that can propagate sound within a propagation region 201 (see Figure 3) and suppress sound propagation in a non-propagation region 202 outside the propagation region 201, and comprises a vibrating member 110, a sound generating device 121, a vibrator 122, a first signal output device 131, and a second signal output device 132. In this embodiment, the acoustic system 100 comprises a housing 140 and a fixing member 150.

[0015] The vibrating member 110 is a member to which vibration is applied by the acoustic generating device 121. The material and shape of the vibrating member 110 are not limited. For example, the vibrating member 110 can be exemplified by a rectangular plate-shaped member made of metal, resin, wood, etc. In the case of the present embodiment, the vibrating member 110 is a plate-shaped member in which the propagation speed of the bending wave propagating in the vibrating member 110 does not exceed the speed of sound in normal temperature air within the frequency range of the sound included in the first acoustic signal reproduced by the acoustic system 100. That is, in the vibration frequency range of the vibration applied by the first vibrator 121, the bending rigidity B and the distributed mass M of the vibrating member 110 are adjusted so that the bending wave propagation speed Cp generated in the vibrating member 110 is slower than the speed of sound Cair≒340 m / s of the air which is the medium of the propagation region 201. Thereby, a non-progressive wave that does not propagate to the non-propagation region 202 can be easily generated in the propagation region 201 near the vibrating member 110 by the operations of the first vibrator 121 and the second vibrator 122. Also, it is desirable that the vibrating member 110 is a plate material in which the Young's modulus E, the material density ρ, the Poisson's ratio ν, and the thickness h are uniformly distributed. The vibrating member 110 closes the opening of the rectangular box-shaped housing 140 and is held by the housing 140 so that the inside of the housing 140 becomes a sealed space. The thickness h of the vibrating member 110 is such that, within the frequency range of the audible sound region, at f = 20 kHz where the bending wave propagation speed Cp is the fastest, the bending rigidity B and the distributed mass M = ρh are adjusted under the first condition so that the bending wave propagation speed Cp is slower than the speed of sound Cair≒340 m / s of the air with respect to the Young's modulus E, the material density ρ, and the Poisson's ratio ν of the vibrating member 110.

[0016] Note that the bending wave propagation speed Cp is obtained by the following formula 1. Cp=(B / M)^(1 / 4)*2^(1 / 2)*(πf)^(1 / 2)…Formula 1

[0017] The first condition is the case where the following formula 2 is satisfied. h<(Cair^2 / πf)*((3*ρ*(1-v^2)) / E)^(1 / 2)…Formula 2

[0018] The bending rigidity B is obtained by the following formula 3. B = h^3 * E / (12 * (-v^2 + 1))... Equation 3 ^ indicates exponentiation, * indicates multiplication, / indicates division, + indicates addition, and - indicates subtraction.

[0019] The acoustic generating device 121 is a device that generates sound toward the vibration member 110 based on the first acoustic signal. The acoustic system 100 may include one or more acoustic generating devices 121. The type of the acoustic generating device 121 is not limited. For example, the acoustic generating device 121 can be exemplified by a speaker unit, an acoustic vibration generator that vibrates an object to emit sound, etc. Also, the acoustic generating device 121 may include a cabinet (enclosure) that houses the speaker unit, a vibration member to which the acoustic vibration generator is attached, etc. Further, the acoustic generating device 121 may include a plurality of speaker units, a plurality of acoustic vibration generators, and may be a multi-way speaker including a plurality of types of speaker units. In the case of this embodiment, the acoustic generating device 121 is a sealed speaker including a cabinet that houses the back surface of the speaker unit in a sealed state. The acoustic generating device 121 is arranged in a state of being housed inside the housing 140.

[0020] The vibrator 122 is an actuator (exciter) attached to the vibrating member 110 that applies vibration to the vibrating member 110 by an excitation force generated based on the second acoustic signal. The vibrator 122 may be of the same type as the vibrator used in the sound generating device 121, or it may be of a different type. The vibrator 122 comprises a second movable part 125 connected to the vibrating member 110, a second base part 126, and a vibration unit (not shown) that generates an excitation force between the second movable part 125 and the second base part 126. The type of vibration unit of the vibrator 122 is not limited, and examples include those using magnets, piezoelectric elements, magnetostrictive elements, etc. The vibrator 122 may also utilize the inertial force generated by the mass effect of the second base part 126, or the structural reaction force generated by connecting one end of the second base part 126 to another structural member, etc. Furthermore, the acoustic system 100 may have one or more vibrators 122. The mounting position of the vibrator 122 is not limited. In this embodiment, the vibrator 122 is mounted on the first surface opposite to the second surface of the vibrating member 110 to which the sound generating device 121 is attached. The acoustic system 100 has one vibrator 122 in the center of the vibrating member 110.

[0021] The first signal output device 131 is a device that outputs the first acoustic signal to the sound generator 121. The first signal output device 131 is not limited, but in this embodiment, it includes a first drive amplifier 133. The first drive amplifier 133 is an amplifier that amplifies the first acoustic signal output from the signal source 200 until it can drive the sound generator 121 to emit sound from the vibrating member 110. The first signal output device 131 may also be equipped with any filters such as a delay filter or a correction filter.

[0022] The second signal output device 132 is a device that outputs a second acoustic signal to the exciter 122, which is a corrected version of the first acoustic signal that suppresses sound propagation in the non-propagation region 202, which is outside the propagation region 201, where sound emitted from the sound generator 121 based on the first acoustic signal and passed through the vibrating member 110 is intended to propagate in the air. The second signal output device 132 is not limited, but in this embodiment it includes a second drive amplifier 134. The second drive amplifier 134 drives the exciter 122 to vibrate the vibrating member 110 and amplifies the second acoustic signal that has been corrected to suppress sound propagation in the non-propagation region 202. In this embodiment, the second drive amplifier 134 amplifies the second acoustic signal that has been corrected by the correction filter 135.

[0023] The correction filter 135 is a filter that outputs a second sound signal to the exciter 122, which is a corrected version of the first sound signal, allowing the sound emitted by the vibrating member 110 vibrated by the sound generator 121 to propagate within the propagation region 201 where propagation is intended, and suppressing sound propagation in the non-propagation region 202 where propagation is not intended. The propagation region 201 is located near the vibrating member 110, and the non-propagation region 202 is the region adjacent to the vibrating member 110 at a greater distance than the propagation region 201. The correction filter 135 has filter characteristics G specific to the sound system 100. The filter characteristics G of the correction filter 135 are derived based on the transmission characteristics of the sound emitted and propagated by the exciter 122 vibrating the vibrating member 110.

[0024] Next, a characteristic creation system 300 that can set the filter characteristics G of the correction filter 135 provided in the acoustic system 100 will be described. Figure 4 shows the characteristic creation system 300 in the first measurement mode. Figure 5 shows the characteristic creation system 300 in the second measurement mode. The characteristic creation system 300 is a system for creating the filter characteristics G of the correction filter 135 provided in the acoustic system 100, and comprises an acoustic system 100 in which the filter characteristics G has not been set, a characteristic creation unit 340, and a measuring device 350. In this embodiment, the acoustic system 100 is equipped with a first changeover switch 371, a second changeover switch 372, and a third changeover switch 373.

[0025] The filter characteristics G are created based on a first acoustic signal for measurement. Examples of the first acoustic signal for measurement include a predetermined acoustic signal, a sine wave signal, a sweep sine signal, an impulse signal, a random noise signal, a colored noise signal, an M-sequence signal, and a TSP (time-stretched pulse) signal.

[0026] The measuring device 350 is a device that measures the sound generated by the acoustic system 100. A microphone can be used as an example of the measuring device 350 for measuring sound. Alternatively, a displacement sensor, velocity sensor, acceleration sensor, etc., may be used as the measuring device 350.

[0027] The characteristic creation unit 340 places measuring devices 350 at one or more locations within the non-propagation region 202 and creates the filter characteristics G of the correction filter 135 based on a first sound pressure transfer function H1 between the first sound signal and the first measurement signal P1, which is the sound emitted from the sound generator 121 based on the first sound signal and passed through the vibrating member 110, measured by the measuring device 350, and a second sound pressure transfer function H2 between the second sound signal and the second measurement signal P2, which is the sound emitted from the vibrating member 110 due to the excitation force generated by the exciter 122 based on the first sound signal, measured by the measuring device 350, and a second sound pressure transfer function H2 between the second sound signal and the second measurement signal. In this embodiment, the characteristic creation unit 340 derives the filter characteristics G using a Fourier transform. The specific derivation method will be described later. The characteristic creation unit 340 is a processing unit that is realized by having a processor in a dedicated or general-purpose computer execute a characteristic creation program.

[0028] Next, a method for manufacturing the acoustic system 100 using the characteristic creation system 300 will be described. As shown in Figure 4, the acoustic system 100 is placed in a predetermined location. In addition, a measuring device 350 is placed at the boundary between the propagation region 201 and the non-propagation region 202.

[0029] Based on the first acoustic signal S1, the first changeover switch 371 and the second changeover switch 372 are switched to generate sound using the sound generator 121 (see Figure 4). At this time, the third changeover switch 373 is switched so that the vibrator 122 is short-circuited.

[0030] The sound generated from the sound generator 121 and passing through the vibrating member 110 is measured by the measuring device 350 to obtain the first measurement signal P1. The characteristic creation unit 340 derives the first sound pressure transfer function H1 between the first sound signal S1 and the first measurement signal P1.

[0031] Next, the first changeover switch 371 and the third changeover switch 373 are switched so that the exciter 122 generates sound based on the second acoustic signal S2 (see Figure 5). At this time, the second changeover switch 372 may also be switched so that the sound generator 121 is short-circuited. The second acoustic signal S2 is the uncorrected first acoustic signal S1. In other words, the second acoustic signal S2 is identical to the first acoustic signal S1.

[0032] Without changing the position of the measuring device 350 that measured the first measurement signal P1, the sound generated by the vibrator 122 vibrating the vibrating member 110 based on the second acoustic signal S2 is measured by the measuring device 350 to measure the second measurement signal P2. The characteristic creation unit 340 derives the second sound pressure transfer function H2 between the second acoustic signal S2 and the second measurement signal P2, and together with the first sound pressure transfer function H1 derived earlier, derives the filter characteristics G of the correction filter 135.

[0033] The sound system 100 can be manufactured by setting the filter characteristics G of the correction filter 135 created by the characteristic creation unit 340 to the correction filter 135 provided in the sound system 100.

[0034] It should be noted that the present invention is not limited to the embodiments described above. For example, other embodiments of the present invention may be realized by arbitrarily combining the components described herein, or by excluding some of the components. Furthermore, modifications obtained by applying various modifications to the above embodiments that a person skilled in the art could conceive of without departing from the spirit of the present invention, that is, the meaning indicated by the wording in the claims, are also included in the present invention.

[0035] For example, the case described above involves measuring the first measurement signal P1 and the second measurement signal P2 in one location using a measuring device 350, and deriving the filter characteristics G for the correction filter 135. However, as shown in Figure 6, it is also possible to measure multiple first measurement signals P1 and multiple second measurement signals P2 by arranging multiple measuring devices 350 in multiple locations, or by changing the position of the measuring devices 350, and derive the filter characteristics G. In this case, the filter characteristics G of the correction filter may be derived based on the first sound pressure transfer function H1 between the first processed signal obtained by statistically processing the first measurement signal P1 measured at a number of locations different from the number of sound generators 121 attached to the vibrating member 110 and the first sound signal S1, and the second sound pressure transfer function H2 between the second processed signal obtained by statistically processing the second measurement signal P2 measured at a number of locations different from the number of exciters 122 attached to the vibrating member 110 and the second sound signal S2.

[0036] Furthermore, as shown in Figure 7, multiple vibrators 122 may be attached to the vibrating member 110. Also, the vibrators 122 may be attached to the second surface of the vibrating member 110, which is the surface facing the sound generating device 121.

[0037] Furthermore, although an example was given of manufacturing the acoustic system 100 by setting the filter characteristics G derived from the measurement results based on the characteristic creation system 300 to the correction filter 135, it is also acceptable to derive the filter characteristics G of the correction filter 135 by numerical analysis simulation such as FEM (finite element method) or LEM (equivalent circuit analysis method using lumped elements) and set it to the correction filter 135 of the acoustic system 100.

[0038] Furthermore, although the characteristic creation system 300 was described in the case where the second changeover switch 372 and the third changeover switch 373 are placed on the output terminal side of the first drive amplifier 133 and the second drive amplifier 134, they may also be placed on the input terminal side. In this case, if a voltage-driven amplifier with a sufficiently low output impedance is used as the measurement amplifier, the same effect as short-circuiting the changeover switch placed on the output terminal side can be obtained by short-circuiting the input terminal of the measurement amplifier to ground potential.

[0039] Alternatively, as shown in Figure 8, the second base portion 126 of the vibrator 122 may be connected to the fixing member 150.

[0040] (summary) The acoustic system 100 of the first embodiment includes a vibrating member 110, one or more sound generating devices 121 that generate sound directed toward the vibrating member 110 based on an acoustic signal, one or more vibrators 122 attached to the vibrating member 110 and that vibrate the vibrating member 110, a first signal output device 131 that outputs a first acoustic signal to the sound generating device 121, and a second signal output device 132 that outputs a second acoustic signal to the vibrators 122, which is a corrected version of the first acoustic signal that suppresses sound propagation in a non-propagation region 202 that is outside the region where sound emitted from the sound generating device 121 and passed through the vibrating member 110 is intended to propagate.

[0041] According to the first embodiment, sound can be propagated to the propagation region 201, which is the intended area near the vibrating member 110, while suppressing sound propagation in the non-propagation region 202, which is an area where sound propagation is difficult to suppress with conventional devices and methods. Therefore, it is possible to arbitrarily create a space where sound is delivered only to people within the propagation region 201 near the sound system 100, and where sound is less likely to reach people outside the propagation region 201. Such a space can be created, for example, in the cabin of an airplane or inside a car, where sound is delivered to people sitting in designated seats, while people sitting in other seats can listen to other sounds or enjoy conversations.

[0042] The acoustic system 100 of the second embodiment includes the first embodiment, wherein the vibrating member 110 is plate-shaped such that the propagation speed of the bending wave does not exceed the speed of sound in room temperature air within the frequency range of the sound included in the first acoustic signal.

[0043] The third embodiment of the acoustic system 100 includes the first or second embodiment and comprises a housing 140 that holds a vibrating member 110 and together with the vibrating member 110 forms a sealed space, and the sound generating device 121 is arranged inside the housing 140.

[0044] According to the third embodiment, sound can be strongly propagated in a predetermined direction.

[0045] The fourth embodiment of the acoustic system 100 includes any of the first to third embodiments and comprises a fixing member 150 that fixes the portion of the exciter 122 opposite to the vibrating member 110.

[0046] According to the fourth embodiment, by connecting the second base portion 126 of the vibrator 122 to the fixing member 150, the vibrating member 110 can be vibrated using structural reaction forces. Therefore, even if the vibrator 122 is lightweight, for example, the excitation force can be effectively transmitted to the vibrating member 110, and the propagation of sound in the non-propagation region 202 can be effectively suppressed.

[0047] The fifth embodiment of the acoustic system 100 includes any of the first to fourth embodiments, and the second signal output device 132 includes a correction filter 135 that corrects the first acoustic signal and outputs it to the exciter 122, and the correction filter 135 includes filter characteristics G derived based on the transmission characteristics of sound emitted by the sound generator 121 and propagated through the vibrating member 110.

[0048] The sixth embodiment of the sound system control method is a method for setting the filter characteristics G of a correction filter 135 provided in the sound system 100 of the fifth embodiment, wherein measuring devices 350 are placed at one or more locations within the non-propagation region 202, and the filter characteristics G of the correction filter 135 are set based on a first sound pressure transfer function between the first sound signal and a first measurement signal measured by the measuring device 350 of sound emitted from the sound generator 121 and propagating through the vibrating member 110 based on a first sound signal, and a second sound pressure transfer function between the second sound signal and a second measurement signal measured by the measuring device 350 of sound emitted from the vibrating member 110 due to the excitation force generated by the exciter 122 based on a second sound signal, and a second sound pressure transfer function between the second sound signal.

[0049] The seventh embodiment of the method for manufacturing an acoustic system is a method for manufacturing an acoustic system 100 by setting the filter characteristics G of a correction filter 135 provided in the acoustic system 100 of the fifth embodiment, wherein measuring devices 350 are placed at one or more locations within the non-propagation region 202, and the filter characteristics G of the correction filter 135 are set based on a first sound pressure transfer function between the first sound signal and a first measurement signal measured by the measuring device 350 of sound emitted from the vibrating member 110 due to the excitation force generated by the sound generator 121 based on a first acoustic signal, and a second sound pressure transfer function between the second sound signal and a second measurement signal measured by the measuring device 350 of sound emitted from the vibrating member 110 due to the excitation force generated by the vibrator 122 based on a second acoustic signal, and a second sound pressure transfer function between the second sound signal.

[0050] According to the sixth and seventh embodiments, the filter characteristics G of the correction filter 135 corresponding to the sound system 100 can be appropriately set. This allows sound emitted from the sound generator 121 to propagate in the propagation region 201, which is the intended region, while suppressing sound propagation to the non-propagation region 202.

[0051] The eighth embodiment of the method for manufacturing an acoustic system includes the seventh embodiment, wherein a first measurement signal is acquired with the vibrator 122 in a short-circuited state.

[0052] The ninth embodiment of the method for manufacturing an acoustic system includes the seventh embodiment, wherein a second measurement signal is acquired when the acoustic generator 121 is short-circuited.

[0053] According to the eighth and ninth embodiments, the influence of an undriven vibrator 122 or sound generator 121 on the measurement can be suppressed.

[0054] The tenth embodiment of the acoustic system manufacturing method includes any of the seventh to ninth embodiments, and sets the filter characteristics G of the correction filter 135 based on a first sound pressure transfer function between a first processed signal and a first acoustic signal obtained by statistically processing a first measurement signal measured at a number of positions different from the number of positions of the sound generating device 121, and a second sound pressure transfer function between a second processed signal and a second acoustic signal obtained by statistically processing a second measurement signal measured at a number of positions different from the number of positions of the exciters 122 attached to the vibrating member 110.

[0055] If the number of measurement signals (number of measurement positions) matches the number of sound generators 121 or vibrators 122 driven during measurement, the derived filter characteristic G is uniquely determined, which may result in the creation of unintended processing signals. On the other hand, according to the tenth embodiment, by making the number of measurement signals (number of measurement positions) and the number of vibrators not match, a robust control filter can be calculated without creating unintended processing signals. [Industrial applicability]

[0056] This disclosure can be used in sound systems installed in spaces where multiple people gather closely, such as airplane cabins, car interiors, offices, and restaurants. [Explanation of symbols]

[0057] 100 Sound Systems 110 Vibrating member 121 Sound Generator 122 Vibrator 125 Second moving part 126 Second base 131 First signal output device 132 Second signal output device 133 First drive amplifier 134 Second drive amplifier 135 Correction Filter 140 cabinets 150 Fixing member 200 signal source 201 Propagation Region 202 Non-propagation region 300 Characteristic Creation System 340 Characterization Section 350 measuring devices 371 First changeover switch 372 Second changeover switch 373 Third changeover switch

Claims

1. Vibrating member and One or more sound generating devices that generate sound directed toward the vibrating member based on an acoustic signal, One or more vibrators attached to the vibrating member and applied vibration to the vibrating member, The sound generating device includes a first signal output device that outputs a first sound signal, A second signal output device outputs a second acoustic signal to the vibrator, which is a corrected version of the first acoustic signal obtained by modifying the first acoustic signal to suppress the propagation of sound in a non-propagation region that is outside the region where sound emitted from the sound generating device based on the first acoustic signal and passed through the vibrating member is intended to propagate. An acoustic system equipped with [unspecified features].

2. The vibrating member is Within the frequency range of the sound contained in the first acoustic signal, the bending wave propagation speed does not exceed the speed of sound in room temperature air, and the plate is shaped accordingly. The acoustic system according to claim 1.

3. The housing includes a structure that holds the vibrating member and forms a sealed space together with the vibrating member, The sound generating device is arranged inside the housing. The acoustic system according to claim 1 or 2.

4. The vibrator is equipped with a fixing member that secures the portion of the vibrator opposite to the vibrating member. The acoustic system according to claim 1 or 2.

5. The second signal output device is, The system includes a correction filter that corrects the first acoustic signal and outputs it to the vibrator, The aforementioned correction filter is The filter characteristics are derived based on the transmission characteristics of the sound emitted by the sound generating device and propagated through the vibrating member. The acoustic system according to claim 1 or 2.

6. A method for controlling an acoustic system to set the filter characteristics of a correction filter provided in the acoustic system described in claim 5, Measuring devices are placed at one or more locations within the non-propagation region. A first sound pressure transfer function between the first acoustic signal and the sound emitted from the sound generating device and propagated through the vibrating member, measured by the measuring device, and the first acoustic signal, A second sound pressure transfer function between the second acoustic signal and the second sound pressure transfer function, which is a second measurement signal obtained by measuring the sound emitted from the vibrating member by the excitation force generated by the vibrator based on the second acoustic signal, and the second acoustic signal, The filter characteristics of the correction filter are set based on this. A method for controlling an acoustic system.

7. A method for manufacturing an acoustic system, comprising setting the filter characteristics of a correction filter included in the acoustic system described in claim 5, Measuring devices are placed at one or more locations within the non-propagation region. Based on the first acoustic signal, the sound emitted from the vibrating member by the excitation force generated by the sound generating device is measured by the measuring device as a first measurement signal, The first sound pressure transfer function between the first acoustic signal and the first sound signal, The second measurement signal is the sound emitted from the vibrating member by the excitation force generated by the vibrator based on the second acoustic signal, measured by the measuring device. The second sound pressure transfer function between the second acoustic signal and the second sound signal, The filter characteristics of the correction filter are set based on this. Method for manufacturing an acoustic system.

8. The first measurement signal is acquired when the vibrator is short-circuited. The method for manufacturing an acoustic system according to claim 7.

9. The second measurement signal is acquired when the sound generating device is short-circuited. The method for manufacturing an acoustic system according to claim 7.

10. A first sound pressure transfer function between the first processed signal obtained by statistically processing the first measurement signals measured at a number of positions different from the number of sound generating devices, and the first sound signal, The filter characteristics of the correction filter are set based on the second sound pressure transfer function between the second processed signal, which is obtained by statistically processing the second measurement signals measured at a number of positions different from the number of vibrators attached to the vibrating member, and the second acoustic signal. The method for manufacturing an acoustic system according to claim 7.

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