JP6568020B2 - Sound equipment - Google Patents

Description

  The present invention relates to an acoustic device having a connecting member that connects two vibrators.

  A speaker is disclosed in which exciters are respectively fixed to opposing surfaces of a cylinder (see, for example, Patent Document 1). In this Patent Document 1, only the phase of the frequency component in which the first exciter is vibrated and the standing wave in the second acoustic signal is generated based on the signal obtained by inverting only the phase of the frequency component in which the standing wave in the first acoustic signal is generated. It is described that the second exciter is vibrated on the basis of the inverted signal.

JP 2013-172416 A

The conventional configuration is a technique for suppressing vibration corresponding to a standing wave, and the vibration level cannot be positively improved. For this reason, there is a possibility that a sufficient vibration level cannot be obtained.
Therefore, an object of the present invention is to provide an acoustic device capable of improving a vibration level using a connecting member that connects a plurality of vibrators.

  In order to achieve the above object, an acoustic device of the present invention includes a first vibrator, a second vibrator, a connecting member that connects the first vibrator and the second vibrator, A member to be vibrated to which the connecting member is mounted, and a control unit configured to control the first and second vibrators based on a predetermined signal, wherein the control unit includes the first and second vibrations. In a predetermined frequency band in which vibrations excited by the child with respect to the connecting member are attenuated, the phase of a signal input to one of the vibrators is inverted.

In the above configuration, the predetermined frequency band vibrates one of the vibrators in the normal phase and the other vibrator in the reverse phase as compared with the case where the first and second vibrators vibrate in the normal phase. It may be set to a frequency band where the vibration of the connecting member becomes stronger.
In the above configuration, in the frequency band excluding the predetermined frequency band, the signals input to the first and second vibrators may be positive phase.

In the above configuration, the control unit may be configured not to invert the phase of a signal input to the vibrator in a region having a specified frequency or higher.
In the above configuration, the control unit adds, attenuates, and attenuates two types of acoustic signals constituting the predetermined signal as a process of inverting the phase of the signal input to the one transducer. The phase of the signal may be inverted.

  In the above configuration, the two kinds of acoustic signals may constitute stereo sound.

  In the present invention, in the predetermined frequency band in which the first and second vibrators attenuate the vibrations applied to the connecting member that connects the first vibrator and the second vibrator, Since the phase of the signal input to the vibrator is inverted, the vibration level can be improved by using a connecting member that connects a plurality of vibrators.

It is the figure which showed typically the internal structure of the audio equipment concerning embodiment of this invention with a periphery structure. It is a block diagram of a control apparatus. It is the block diagram which showed the control apparatus at the time of an acoustic measurement process with a periphery structure. It is a flowchart of an acoustic measurement process. It is the figure which showed the frequency characteristic of the acoustic signal acquired by step S1 of FIG. It is the figure which showed the frequency characteristic of the acoustic signal acquired by step S2 of FIG. It is the figure which showed the frequency characteristic of the difference acquired by step S4 of FIG. It is the figure which showed the band division of the band division part. It is the figure which showed the processing content of the phase inversion part. It is the figure which showed the modification of the audio equipment. It is the figure which showed typically the internal structure of the other audio equipment.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram schematically showing an internal structure of an acoustic device 10 according to an embodiment of the present invention together with peripheral configurations.
The acoustic device 10 is an on-vehicle acoustic device mounted on a vehicle such as an automobile, and more specifically, vibration, voice guidance, and vibration for a vehicle occupant (user). It functions as an in-vehicle information transmission device capable of transmitting various information such as voice. The acoustic device 10 is detachably attached to the lower portion of the headrest 11 and also serves as a neck pad that supports the occupant's neck. By attaching the acoustic device 10, the information transmission device can be easily added to a vehicle that does not include this type of information transmission device in advance.
The acoustic device 10 may be configured as an installation type that is installed in advance in the vehicle, or may be attached to a moving body other than the vehicle.

  The acoustic device 10 includes two exciters 21R and 21L that function as first and second vibrators, and a shaft member 23 that constitutes a connecting member that connects the exciters 21R and 21L. Furthermore, the acoustic device 10 includes a pad portion 25 that functions as a neck pad to which the shaft member 23 is attached and a member to be vibrated, and a control device (control portion) 30 that controls the exciters 21R and 21L, which will be described later.

  The exciters 21R and 21L have a thin vibrator 21A such as a flat plate, and the exciters 21R and 21L vibrate respectively when the vibrator 21A vibrates according to a signal input from the outside. The shaft member 23 is vibrated by the vibrations of the exciters 21R and 21L. Since the pad portion 25 is attached to the shaft member 23, the vibration of the shaft member 23 is transmitted to the occupant via the pad portion 25. As a result, particularly low-frequency vibration and bass are recognized by the occupant via the pad portion 25.

  The exciters 21R and 21L of this configuration further include an air vibration member (not shown) that vibrates air (for example, a speaker diaphragm), and the air vibration member vibrates according to the vibration of the vibrator 21A. As a result, it is possible to output a sound having a wider range than the case of the shaft member 23 alone. In addition, a well-known exciter is widely applicable to each exciter 21R, 21L.

  Each exciter 21R, 21L is arranged at intervals in the left-right direction in the vehicle. The left exciter 21L is used as an exciter for the left channel, and the right exciter 21R is used as an exciter for the right channel. Hereinafter, the pair of left and right exciters 21 </ b> R and 21 </ b> L is referred to as an exciter 21 when it is not necessary to distinguish between them.

The shaft member 23 has one end connected to one exciter 21 and the other end connected to the other exciter 21. The shaft member 23 is formed of a solid metal rod extending in a straight line. By connecting the shaft member 23 to the two exciters, the vibration amount (amplitude) can be increased when the vibration direction of the shaft member 23 due to the vibrations of both exciters 21 is synchronized.
The shaft member 23 is not limited to one and may be a plurality. Various rigid bodies can be widely applied to the shaft member 23. For example, a metal hollow bar or a metal plate may be used, or a material other than metal may be used.

The pad portion 25 constitutes a neck pad that is an abutting portion that abuts an occupant, and includes a cushion portion 25A formed of a cushion material such as urethane and a skin 25B that covers the cushion portion 25A. The shaft member 23 penetrates the inside of the pad portion 25 (cushion portion 25A), and vibrates the entire pad portion 25 by the vibration of the shaft member 23.
Thereby, the shaft member 23 is vibrated by the vibration of each exciter 21, and vibration or the like can be transmitted to the occupant via the pad portion 25. The pad portion 25 also serves as a case that houses the exciter 21, the shaft member 23, and the control device 30.

FIG. 2 is a block diagram of the control device 30.
The control device 30 includes an information processing unit 31, a storage unit 32, a band dividing unit 33, a phase inverting unit 34, a band synthesizing unit 35, and an amplifying unit 36. The information processing unit 31 functions as a computer that controls each unit of the control device 30 and an arithmetic processing unit that performs various arithmetic processes by executing the control program stored in the storage unit 32. In addition to the control program, the storage unit 32 can store various data such as parameter information for determining the contents of the band division process and the phase inversion process.

  The control device 30 is configured to be able to input two-channel acoustic signals SL and SR from the outside. The two-channel acoustic signals SL and SR are signals indicating sound and vibration waveforms corresponding to music, voice guidance, warning, or the like, and are, for example, stereo (L, R) audio signals. Note that the acoustic signals SL and SR are both input as positive phase signals.

The band dividing unit 33 performs a band dividing process for dividing the input acoustic signals SL and SR into predetermined frequency bands. The phase inverting unit 34 performs a phase inverting process for inverting one of the phases of the signal for each frequency band output from the band dividing unit 33.
The band synthesizing unit 35 generates a single left channel acoustic signal SLX by synthesizing the acoustic signals corresponding to the plurality of left channels output from the phase inverting unit 34, and also outputs the plurality of signals output from the phase inverting unit 34. The sound signal corresponding to the right channel is synthesized to generate a single right channel sound signal SRX.

  The amplifying unit 36 amplifies the left channel acoustic signal SLX and outputs it to the left channel exciter 21L, amplifies the right channel acoustic signal SRX, and outputs it to the right channel exciter 21R. Each exciter 21 vibrates according to the waveform of the input acoustic signals SLX and SRX. In this way, the control device 30 generates the acoustic signals SLX and SRX from the input signals (acoustic signals SL and SR), and drives each exciter 21 based on the acoustic signals SLX and SRX.

The contents of the above band division processing and phase inversion processing are set by the information processing section 31 based on the parameter information stored in the storage section 32.
This parameter information is information describing a frequency band (hereinafter, referred to as “attenuation generation frequency band Y”) in which vibrations of the left and right exciters 21 that are vibrated with respect to the shaft member 23 are attenuated. This parameter information is obtained by an acoustic measurement process described later.

FIG. 3 is a block diagram showing the control device 30 during the acoustic measurement process together with the peripheral configuration.
As shown in FIG. 3, a sound source unit 37 and a recording unit 38 are connected to the control device 30. The sound source unit 37 is a unit that outputs two measurement signals SL0 and SR0 based on an instruction from the information processing unit 31. In the present embodiment, the sound source unit 37 outputs monaural audio signals having the same left channel and right channel as the measurement signals SL0 and SR0 in phase.

The recording unit 38 is a unit that records an output result (sound or vibration output result) of the control device 30, and outputs an acoustic signal SM indicating the recording result to the control device 30. The recording unit 38 is, for example, a sound collecting microphone, and is installed in the center of the pad unit 25 in order to efficiently record output sound.
Note that the sound source unit 37 and the recording unit 38 are not limited to the configuration provided outside the control device 30, but may be configured within the control device 30.

  FIG. 4 is a flowchart of the acoustic measurement process. As shown in FIG. 4, the sound measurement processing includes monaural sound source reproduction / recording processing (step S1), phase-inverted sound source reproduction / recording processing (step S2), frequency characteristic calculation processing (step S3), and difference calculation. The process (step S4) and the band determination process (step S5) of the phase inversion band Y1 are included.

  As the monaural sound source reproduction / recording process (step S1), the information processing unit 31 causes the sound source unit 37 to output the measurement signals SL0 and SR0, and acquires the acoustic signal SM indicating the output result (recording result). In this case, the band dividing unit 33, the phase inverting unit 34, and the band synthesizing unit 35 do not perform any processing and output the measurement signals SL0 and SR0 as they are.

  The measurement signals SL0 and SR0 are monaural audio signals having the same left channel and right channel, and are generated using M-sequence codes. By using the M-sequence code, an audio signal having a flat signal level and a random phase characteristic over a wide frequency can be obtained. In this case, the acoustic signal SM indicating the output result (recording result) of the monaural audio signals between the positive phases is acquired. When the information processing unit 31 acquires the acoustic signal SM, the information processing unit 31 stores data corresponding to the acoustic signal SM in the storage unit 32.

  The reproduction recording process (step S2) of the phase-inverted sound source is the same as the process in step S1 except that the information processing unit 31 inverts one of the phases of the measurement signals SL0 and SR0 in the phase inversion unit 34. . Thereby, the acoustic signal SM indicating the output result (recording result) of the normal phase and reverse phase monaural audio signals is acquired, and the data corresponding to the acquired acoustic signal SM is stored in the storage unit 32.

Next, as frequency characteristic calculation processing (step S3), the information processing section 31 performs Fourier transform on the data of the acoustic signal SM acquired in steps S1 and S2, and specifies each frequency characteristic.
FIG. 5 shows the frequency characteristic f1 of the acoustic signal SM acquired in step S1. This frequency characteristic f1 is an actual frequency characteristic when each exciter 21 is driven by monophonic audio signals of positive phases.
FIG. 6 shows the frequency characteristic f2 of the acoustic signal SM acquired in step S2. This frequency characteristic f2 is an actual frequency characteristic when each exciter 21 is driven by a monaural audio signal of normal phase and reverse phase. The reason why neither of the frequency characteristics f1 and f2 becomes a flat characteristic is that the natural frequency of each part of the acoustic device 10 and the interference of vibrations from each exciter 21 influence. Also, it is clear from the difference between FIG. 5 and FIG. 6 that the frequency characteristics are different between the case of the in-phase and the case of the opposite phase.

Next, as the difference calculation process (step S4), the information processing section 31 calculates the result of subtracting the frequency characteristic f1 from the frequency characteristic f2 by calculation to obtain the difference frequency characteristic f3.
FIG. 7 shows the frequency characteristic f3 of the difference. From FIG. 5 to FIG. 7, in the case of the in-phase, compared with the case of the opposite phase, particularly the low and low sound ranges are attenuated relatively large, and interference occurs in the piston motion region of the exciter 21. I know that. The piston motion region is a region where the shaft member 23 can move integrally with the exciter 21.

  In addition, hatching shown in FIG. 7 indicates regions AR1, AR2, and AR3 having signal levels of zero dB or more. These regions AR1 to AR3 are regions in which strong vibration is obtained when one exciter 21 is driven in the normal phase and the other exciter 21 is driven in the reverse phase as compared with the case where the left and right exciters 21 are vibrated in the normal phase. is there. In addition, these areas AR1 to AR3 are frequency bands (attenuation generation frequencies) in which vibrations excited by the left and right exciters 21 with respect to the shaft member 23 are attenuated by interference when the left and right exciters 21 are driven in the normal phase. Equivalent to the band Y).

  As the band determination process (step S5) of the phase inversion band Y1, the information processing section 31 specifies the phase inversion band Y1 based on the result of the difference calculation process (step S4). This phase inversion band Y1 is the attenuation generation frequency band Y, and is one in which one exciter 21 is oscillated in the normal phase and the other exciter 21 is oscillated in the opposite phase as compared with the case where both exciters 21 are oscillated in the normal phase. Is a frequency band where strong vibration is obtained.

  The phase inversion band Y1 is limited to a region up to a specified frequency. The prescribed frequency is the upper limit frequency of the piston motion region of the exciter 21, and is set to 2 kHz, which is the upper limit value of the mid range in this configuration. In addition, 70 Hz is set as a lower limit value at which the exciter 21 can perform sound reproduction and vibration reproduction. For this reason, the information processing section 31 specifies the phase inversion band Y1 within the range of 70 Hz to 2 kHz.

  Accordingly, in the example of FIG. 7, as the phase inversion band Y1, the value A (70 Hz) to the value B (500 Hz) corresponding to the area AR1 and the value C (700 Hz) to the value D (1.7 kHz) corresponding to the area AR2. ) Is specified. Note that the area AR3 exceeds the specified frequency and is not specified as the phase inversion band Y1. Each value indicating the phase inversion band Y1 specified in this way is stored in the storage unit 32 as parameter information.

Next, operation | movement of the control apparatus 30 at the time of sound reproduction is demonstrated. The storage unit 32 has already stored parameter information of the phase inversion band Y1.
When reproducing the two-channel acoustic signals SL and SR, first, the information processing section 31 reads parameter information from the storage section 32 and sets the phase inversion band Y1 in the band division section 33 and the phase inversion section 34.
Hereinafter, a case where a value A (70 Hz) to a value B (500 Hz) corresponding to the area AR1 and a value C (700 Hz) to a value D (1.7 kHz) corresponding to the area AR2 are set as the phase inversion band Y1. This will be described below.

FIG. 8 is a diagram illustrating the band division of the band dividing unit 33.
As shown in FIG. 8, the band dividing unit 33 divides the frequency band of the input stereo audio signals SL and SR into a value B (500 Hz) or less, a value B (500 Hz) to a value C (value B). It is divided into four areas: a division 2 area of 700 Hz), a division 3 area of value C (700 Hz) to a value D (1.7 kHz), and a division 4 of value D (1.7 kHz) or more. In addition, since it is below the lower limit which can reproduce the sound and vibration of the exciter 21, 70 Hz or less is not divided.
As a result, as shown in FIG. 2, the acoustic signals SL and SR are acoustic signals SL1 and SR1 corresponding to the division 1, the acoustic signals SL2 and SR2 corresponding to the division 2, the acoustic signals SL3 and SR3 corresponding to the division 3, And divided into acoustic signals SL4 and SR4 corresponding to division 4.

Based on the setting of the phase inversion band Y1, the phase inversion unit 34 divides the acoustic signals SL, SR into the above four bands, among the signals obtained by dividing the acoustic signals SL1, SR1, and division 3 (corresponding to AR2). The phase is inverted with respect to the acoustic signals SL3 and SR3 (corresponding to AR2).
In this case, as shown in FIG. 9, the phase inverting unit 34 adds the left and right channel acoustic signals SL1 and SR1 by the adding unit 34A and attenuates the added signal by the attenuator 34B. The attenuated signal is output as the acoustic signal SL1A, and the phase is inverted by the inverting unit 34C and output as the acoustic signal SR1A. That is, the left and right channel acoustic signals SL1 and SR1 are added and attenuated, and the left and right channel acoustic signals SL1 and SR1 are added and attenuated and the phase inverted acoustic signal SL2A is output. .

The reason for attenuating the added signal is to match the signal level with the other acoustic signals SL2, SR2, SL4 and SR4.
Further, the phase inverting unit 34 also adds the two types of acoustic signals SL3 and SR3 and attenuates the acoustic signals SL3 and SR3, and the two types of acoustic signals SL3 and SR3, similarly to the acoustic signals SL1 and SR1. SL1 and SR1 are added and attenuated to generate and output an acoustic signal SL23 whose phase is inverted.
In this embodiment, the case where the phase of the right channel is inverted is described. However, the present invention is not limited to this, and the phase of the left channel may be inverted.

Next, the band synthesizer 35 synthesizes the divided and phase-inverted signals of the respective bands, and outputs the acoustic signal SLX output to the left channel exciter 21L and the acoustic signal SRX output to the right channel exciter 21R, respectively. Generated and output to each exciter 21 via the amplifier 36.
In this case, the acoustic signal SLX is a signal obtained by synthesizing the left channel acoustic signals SL1A, SL2, SL3A, and SL4, and the acoustic signal SRX is a signal obtained by synthesizing the right channel acoustic signals SR1A, SR2, SR3A, and SR4. . Thereby, each exciter 21 is driven by each of the acoustic signals SLX and SRX, and the corresponding vibration and sound are output. The above is the sound reproduction operation of the sound signals SL and SR.

  As described above, in the present embodiment, during sound reproduction, the phase of the signal input to one of the left and right exciters 21 is inverted in the frequency band corresponding to the phase inversion band Y1. The phase inversion band Y1 is a frequency band (corresponding to the attenuation generation frequency band Y) in which vibrations generated by the left and right exciters 21 being vibrated with respect to the shaft member 23 are attenuated. As a result, attenuation due to vibration interference can be suppressed, and the vibration level (also referred to as amplitude) of the shaft member 23 can be improved. In this case, since attenuation in a specific frequency band is suppressed, it becomes easy to perform highly accurate vibration reproduction in a wide frequency band.

  Further, in this configuration, in the phase inversion band Y1, when the left and right exciters 21 are vibrated in the normal phase, it is more effective to vibrate one exciter 21 in the normal phase and the other exciter 21 in the reverse phase. The frequency band where the vibration of the member 23 is strong is set. Thereby, a vibration level can be improved efficiently. Therefore, even if a small exciter is used as the exciter 21, it is easy to ensure a sufficient vibration level, and it is easy to ensure the vibration amount and volume.

Furthermore, in this configuration, in the frequency band excluding the phase inversion band Y1, since the signals input to the left and right exciters 21 are in the normal phase, it is possible to suppress a sense of discomfort in the audibility that may occur due to the reverse phase. it can.
Further, in this configuration, the phase input to the exciter 21 is not inverted in a region of a specified frequency or higher. As a result, the phase can be reversed only in a predetermined operating range of the exciter 21, for example, only in the piston motion region. Accordingly, the divided vibration region of the exciter 21 can be vibrated in the normal phase, and a sense of incongruity due to the reverse phase in the divided vibration region can be avoided.

Furthermore, in this configuration, as a process of inverting the phase of the signal input to one exciter 21, two types of acoustic signals SL1 and SR1 (same for SL3 and SR3) are added and attenuated, and the phase of the attenuated signal is added. Is reversed. Thereby, the vibration corresponding to both of two types of acoustic signals can be output from one exciter 21, and this can also improve the vibration level.
Further, in this configuration, the other exciter 21 also adds and attenuates two types of acoustic signals SL1 and SR1 (same for SL3 and SR3), and outputs a vibration corresponding to the attenuated signal. The vibration level can be improved.

  Here, if the two types of acoustic signals SL1 and SR1 (same for SL3 and SR3) constituting stereo sound are added, the stereo effect may be difficult to obtain. However, the exciter 21, which is the vibrator of this configuration, In addition, it reproduces low-frequency vibrations that are difficult for humans to recognize the stereo effect. For this reason, it is not disadvantageous for vibration reproduction in the low sound range. Further, in this configuration, since the phase input to the exciter 21 is not inverted in a region above the specified frequency, stereo presence can be maintained in a region above the specified frequency, for example, in the middle sound range and the high sound range.

  Also, as a process of inverting the phase, instead of the above process, the phase of either one of the acoustic signals SL1 and SR1 (same for SL3 and SR3) is inverted and only the inverted signal is input to one exciter 21. May be. Also, the other exciter 21 may be input with the other of the acoustic signals SL1 and SR1 (same for SL3 and SR3) as it is.

The above-described embodiments are merely illustrative of one embodiment of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the exciter 21 is used as the vibrator of the acoustic device 10 has been described. However, the present invention is not limited to this, and known vibrators can be widely applied.

  Moreover, although embodiment mentioned above demonstrated the case where the audio apparatus 10 shared a neck pad, it is not restricted to this. For example, as shown in FIG. 10, the acoustic device 10 may be configured to also serve as a cushion that supports the occupant's waist. FIG. 10 is a perspective view of the occupant seat 40 as viewed obliquely from behind, and the acoustic device 10 is disposed so as to be in close contact with a boundary portion formed by the seating portion 41 and the backrest 42 of the occupant seat 40. . Further, from this acoustic device 10, a belt-like portion 27 extends, and this portion 27 is pushed into the gap between the seating portion 41 and the backrest 42, whereby the acoustic device 10 has a passenger seat 40. Dropping is prevented.

FIG. 11 is a diagram schematically showing the internal structure of another acoustic device 100.
This acoustic device 100 is different from the embodiment shown in FIG. 1 in that the shaft member 23 connecting the exciters 21R and 21L is separated at the center. That is, the shaft member 23 includes a first shaft member 23R extending from the left exciter 21R toward the right exciter 21L, and a second shaft member 23L extending from the right exciter 21L toward the left exciter 21R. .

  With this configuration, the vibration transmitted from the right exciter 21R to the occupant via the first shaft member 23R and the vibration transmitted from the left exciter 21L to the occupant via the second shaft member 23L are separated from each other left and right. Can be generated. Thereby, the vibration can be divided into left and right, and vibration coming from the left side and vibration coming from the right side can be realized. As a result, various vibration variations can be realized.

  The pad portion 25 of the acoustic device 100 shown in FIG. 11 includes left and right sides that cover both the left and right sides of the cushion portion 25A in addition to the cushion portion 25A that functions as a cushion that supports the occupant's waist and the skin 25B that covers the cushion portion 25A. It has a pair of cover parts 29R and 29L. The cushion portion 25A has a pair of left and right recessed portions 25K that are recessed inward from both left and right ends, and the exciters 21R and 21L are respectively disposed in the recessed portions 25K. The pair of left and right cover portions 29R and 29L covers the respective recessed portions 25K, thereby restricting the exposure of the exciters 21R and 21L to the outside.

  The cover portions 29R and 29L may also serve as a protective member that covers the sound from the exciters 21R and 21R so that the sound can be output to the outside, that is, the speaker cover. In addition, by making the pad portion 25 into a neck pad shape, the acoustic device 100 can also be used as a neck pad.

  Furthermore, a combination of both the neck pad type acoustic device 10 shown in FIG. 1 and the waist pad type acoustic device 100 shown in FIG. 11 can realize various variations of vibration.

10, 100 Acoustic device 11 Headrest device (sound collecting device)
21, 21R, 21L exciter (first vibrator, second vibrator)
23 Shaft member (connection member)
25 Pad part (vibrated member) speaker 30 Control device (control part)
31 Information Processing Unit 32 Storage Unit 33 Band Division Unit 34 Phase Inversion Unit 35 Band Synthesis Unit 36 Amplification Unit 37 Sound Source Unit 38 Recording Unit

Claims (6)

A first vibrator,
A second vibrator,
A connecting member for connecting the first vibrator and the second vibrator;
A to-be-vibrated member to which the connecting member is attached;
A control unit for controlling the first and second vibrators based on a predetermined signal,
The control unit reverses the phase of a signal input to one of the vibrators in a predetermined frequency band in which vibrations of the first and second vibrators that vibrate the connection member are attenuated. An acoustic device characterized by the above.   Compared with the case where the first and second vibrators vibrate in the normal phase, the predetermined frequency band is obtained by vibrating one of the vibrators in the normal phase and the other vibrator in the reverse phase. The acoustic device according to claim 1, wherein the acoustic device is set to a frequency band in which vibration of the connecting member is strong.   3. The acoustic device according to claim 1, wherein in a frequency band excluding the predetermined frequency band, signals input to the first and second vibrators are in a positive phase.   4. The acoustic device according to claim 1, wherein the control unit does not invert a phase of a signal input to the vibrator in a region having a specified frequency or higher. 5. The control unit as a process of inverting the phase of the signal input to the one vibrator,
The acoustic apparatus according to claim 1, wherein two kinds of acoustic signals constituting the predetermined signal are added and attenuated, and the phase of the attenuated signal is inverted.   The acoustic device according to claim 5, wherein the two types of acoustic signals constitute stereo sound.

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