JP5716409B2 - Musical instrument - Google Patents

Description

  The present invention relates to a technique for changing the sound quality of a musical instrument having a diaphragm.

  As a technique for adding an acoustic effect to a musical instrument sound, there is a technique that performs signal processing after the sound is once converted into an electric signal. There is also a technique for mechanically imparting an acoustic effect by attaching an actuator to a piano soundboard or the like. For example, Patent Document 1 describes a technique in which signal processing is performed on a vibration signal of a string detected by a sensor, and a soundboard is vibrated by operating an actuator so as to generate sound from the soundboard.

Japanese Patent Laid-Open No. 5-73039

By the way, the sound quality of a stringed instrument such as a piano is largely due to the vibration characteristics of a diaphragm such as a soundboard that emits sound. Therefore, in order to produce sound with various sound quality in one musical instrument, it is necessary to change the vibration characteristics of the diaphragm. In that case, the diaphragm itself must be replaced, which is not practical. It was.
In the technique described in Patent Document 1 described above, it is possible to produce a sound different from a normal piano sound. However, since the actuator is directly attached to the soundboard, the actuator is generated in itself. While the soundboard is vibrated by the inertial force, the entire actuator is also vibrated in accordance with the vibration of the soundboard. For this reason, the physical vibration characteristics of the soundboard itself hardly change, and the soundboard is practically used as a speaker. Therefore, in the configuration of Patent Document 1, the sound quality of the musical instrument itself is greatly changed by processing the vibration sound of the string and generating a sound from the soundboard, even though a sound different from the normal musical instrument sound can be added. It was not a thing.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to change the sound quality of sound produced by controlling the vibration characteristics of a diaphragm in a musical instrument having a diaphragm.

In order to solve the above-mentioned problem, the present invention is connected to a vibrating string, a string support part that supports the string, and the string support part, and vibration of the string is transmitted through the string support part. A diaphragm, a structure that supports the diaphragm, a force detection sensor that detects a force received from the diaphragm and the string, and outputs a force detection signal indicating a detection result; and a force applied to the diaphragm An actuator that operates to vibrate; a member that is connected to the structure and is more rigid than the diaphragm, and a support member that supports the actuator so that the actuator is connected to the diaphragm; There is provided a musical instrument comprising: a control unit that controls the operation of the actuator so that a force corresponding to the force detection signal is applied to a portion of the diaphragm to which the string support unit is connected. .

  In another preferred aspect, the portion of the diaphragm to which the actuator is connected is a portion to which the string support portion is connected.

In another preferred embodiment, a vibration state of a part of the diaphragm having a physical quantity different from the second actuator that operates to vibrate the diaphragm by applying force to the force detection sensor. And a vibration detection sensor that outputs a vibration detection signal indicating a detection result, and the control unit applies the force corresponding to the vibration detection signal to a part of the diaphragm . The operation of the second actuator is controlled. In another preferred embodiment, a part of the diaphragm is a part connected to the second actuator of the diaphragm. In another preferable aspect, the apparatus further includes a second vibration detection sensor that detects a vibration state of the support member and outputs a second vibration detection signal indicating a detection result, and the control unit includes the vibration detection signal and the vibration detection signal. The operation of the second actuator is controlled so that a force corresponding to the second vibration detection signal is applied to a part of the diaphragm.

The present invention also provides a diaphragm, a structure that supports the diaphragm, a vibration detection sensor that detects a vibration state of a part of the diaphragm and outputs a vibration detection signal indicating a detection result, and the vibration. An actuator that operates to vibrate by applying a force to a plate, and a member that is connected to the structure and has higher rigidity than the diaphragm , and the actuator is connected to the diaphragm so that the actuator is connected to the diaphragm. Provided is a musical instrument comprising: a supporting member to support; and a control unit that controls the operation of the actuator so that a force corresponding to the vibration detection signal is applied to a part of the diaphragm. .

  In another preferred embodiment, a part of the diaphragm is a part connected to the actuator of the diaphragm.

  In another preferable aspect, the apparatus further includes a second vibration detection sensor that detects a vibration state of the support member and outputs a second vibration detection signal indicating a detection result, and the control unit includes the vibration detection signal and the vibration detection signal. The operation of the actuator is controlled so that a force corresponding to the second vibration detection signal is applied to a part of the diaphragm.

  ADVANTAGE OF THE INVENTION According to this invention, in the musical instrument which has a diaphragm, the sound quality produced can be changed by controlling the vibration characteristic of a diaphragm.

It is a figure explaining the external appearance of the guitar in embodiment of this invention. It is a front view of the trunk | drum in embodiment of this invention. It is sectional drawing of the trunk | drum seen from the arrow III-III direction shown in FIG. It is a figure explaining the structure of the actuator vicinity in embodiment of this invention. It is a block diagram explaining the structure of the control part in embodiment of this invention. It is a figure explaining the model of control in the control part in the embodiment of the present invention. It is a figure explaining an example of the difference in the frequency characteristic by the operation presence or absence of the actuator in the control according to an acceleration. It is a figure explaining an example of the difference in the frequency characteristic by the operation presence or absence of the actuator in control according to speed. It is a figure explaining an example of the difference in the frequency characteristic by the operation presence or absence of the actuator in the control according to force. It is a front view of the trunk | drum in the modification 1 of this invention. It is sectional drawing of the trunk | drum seen from the arrow XI-XI direction shown in FIG. It is a front view of the trunk | drum of another aspect in the modification 1 of this invention. It is sectional drawing of the trunk | drum seen from the arrow XIII-XIII direction shown in FIG. It is a front view of the trunk | drum of another aspect in the modification 1 of this invention. It is sectional drawing of the trunk | drum seen from the arrow XV-XV direction shown in FIG. It is a front view of the trunk | drum in the modification 2 of this invention. It is sectional drawing of the trunk | drum seen from the arrow XVII-XVII direction shown in FIG. It is a block diagram explaining the structure of the control part in the modification 2 of this invention. It is a figure explaining the example of application to the grand piano of this invention. It is a figure explaining the example of application to the cajon of this invention. It is sectional drawing of the cajon seen from the arrow XXI-XXI direction shown in FIG. It is a block diagram explaining the structure of the control part in the modification 4 of this invention.

<Embodiment>
[Appearance composition]
FIG. 1 is a diagram illustrating the appearance of a guitar 1 according to an embodiment of the present invention. A guitar 1 which is an example of a musical instrument of the present invention has a trunk portion 10. A sound plate 12, a bridge 13, and a saddle 14 are provided on the front plate 11 a of the body portion 10. The vibration of the string 2 is transmitted from the portion connected to the bridge 13 to the front plate 11 a via the saddle 14 that supports the string 2 and the bridge 13 that supports the saddle 14. The vibration of the front plate 11a is also transmitted to the string 2 through the reverse path. The bridge 13 and the saddle 14 function as a string support portion that supports the string 2 as a whole and is connected to the front plate 11a. When the vibration of the string 2 is transmitted to the front plate 11a, the front plate 11a emits a sound corresponding to the vibration. An acceleration sensor 20 is provided on the bridge 13. In this example, the acceleration sensor 20 is provided at a position where it does not contact the saddle 14.

  The side plate 11c of the trunk portion 10 supports the peripheral portion of the front plate 11a. The operation unit 15 is provided on the side plate 11c. The operation unit 15 has an operation panel provided with a rotary switch, operation buttons, and the like. When an operation by the user is accepted, information indicating the operation content is output. The operation unit 15 may be provided with a display unit that displays a menu screen or the like. The operation panel may further be provided with a slot portion into which a recording medium using a nonvolatile memory is inserted. Further, the side plate 11c may be further provided with an input terminal for receiving an audio signal input from the outside.

  FIG. 2 is a front view of the body 10 in the embodiment of the present invention. FIG. 3 is a cross-sectional view of the trunk as seen from the direction of arrows III-III shown in FIG. FIG. 2 is a diagram showing the body 10 extracted from the guitar 1. In the diagrams shown in FIGS. 2 and 3, the description of the strings 2, fingerboard, and the like, which are other components of the guitar 1, is omitted. Moreover, in order to make the positional relationship of each structure demonstrated below easy to understand, description is abbreviate | omitted also about the sound stick provided in the inside of the trunk | drum 10. FIG.

The trunk | drum 10 has internal space BS enclosed by the front board 11a, the back board 11b, and the side board 11c. As described above, the bridge 13 is connected to the front plate 11a. A force detection sensor 30 is provided between the bridge 13 and the saddle 14. The bridge 13 is provided with an acceleration sensor 20.
An end block 55 is provided on the side plate 11c on the inner space BS side. A support member 50 is connected to the end block 55. The actuator 40 is provided in the internal space BS, and is supported by the support member 50 so as to be connected to the front plate 11a. In this example, the portion connected to the front plate 11a of the actuator 40 indicates the positions of the acceleration sensor 20 and the force detection sensor 30 when viewed from the normal direction of the front plate 11a (the direction in which the actuator applies force). It comes to include. The control unit 100 is provided on the support member 50 and controls the operation of the actuator 40 in accordance with signals from the acceleration sensor 20 and the force detection sensor 30.
Next, the configuration in the vicinity of the actuator 40, which is a characteristic part of the present invention, will be described in detail with reference to FIG.

[Configuration near the actuator 40]
FIG. 4 is a diagram illustrating a configuration in the vicinity of the actuator 40 according to the embodiment of the present invention. The acceleration sensor 20 detects the acceleration in the vibration direction (vertical direction in FIG. 4) generated in the acceleration sensor 20 due to the vibration of the front plate 11a. That is, the acceleration sensor 20 detects the acceleration of the portion of the front plate 11a where the sensor is attached. The acceleration sensor 20 outputs an acceleration detection signal Sa indicating the detection result to the control unit 100. The acceleration sensor 20 may use a known configuration such as a semiconductor type, an optical type, or a mechanical type using a MEMS (Micro Electro Mechanical Systems) technology.

  The force detection sensor 30 receives force from the string 2 through the saddle 14 and receives force from the top plate 11 a through the bridge 13. The force detection sensor 30 detects a relative force received from both sides, and outputs a force detection signal Sf indicating the detection result to the control unit 100. This force is a force that the string 2 applies to the front plate 11a in the normal direction (vertical direction in FIG. 4) of the front plate 11a, and is hereinafter referred to as force Fs. The force Fs varies according to the vibration of the string 2 and the vibration of the front plate 11a. The force detection sensor 30 may have a known configuration using, for example, a piezoelectric element, and in this example, has the same configuration as an in-bridge type piezo pickup.

  The actuator 40 operates to apply a force Fa to the front plate 11a in accordance with a drive signal Sp output from the control unit 100 as will be described later. In this example, the actuator 40 is configured to use a voice coil or the like in a speaker. However, any configuration may be used as long as an electrical signal is converted into a mechanical force. Since the actuator 40, the force detection sensor 30, and the acceleration sensor 20 are in the above-described positional relationship, the portion of the front plate 11a to which the force Fa from the actuator 40 is applied is a portion connected to the bridge 13. Therefore, the vibration of the front plate 11 a due to the force Fa from the actuator 40 is directly transmitted to the force detection sensor 30 and the acceleration sensor 20.

Further, since the actuator 40 is supported by the support member 50, the force Fa is applied to the front plate 11a with the support member 50 as a fulcrum. Thus, since the support member 50 is used as a fulcrum by the actuator 40, it is desirable that the support member 50 be a member having higher rigidity than the front plate 11a. Further, it is desirable that the support member 50 is connected to a member that is difficult to transmit the vibration of the front plate 11a. In this example, the support member 50 is connected to a block-shaped end block 55 having a polygonal column shape, and the end block 55 is connected to a side plate 11c extending in a direction substantially perpendicular to the front plate 11a. Therefore, the vibration of the front plate 11a is hardly transmitted to the actuator 40 through the side plate 11c, the end block 55 and the support member 50 as paths.
Next, the configuration of the control unit 100 will be described.

[Configuration of Control Unit 100]
FIG. 5 is a block diagram illustrating the configuration of the control unit 100 according to the embodiment of the present invention. The control unit 100 includes an AD conversion unit 110, a DSP (Digital Signal Processor) 120, a DA conversion unit 130, and an amplification unit 140. The AD conversion unit 110 receives the acceleration detection signal Sa from the acceleration sensor 20, receives the force detection signal Sf from the force detection sensor 30, converts the input signals into digital signals, and outputs the digital signals.

  The DSP 120 uses the acceleration detection signal Sa and the force detection signal Sf input from the AD conversion unit 110 to perform signal processing that performs calculations according to the set parameters, and outputs a calculation signal Sz obtained as a calculation result. . The parameters are set according to an operation signal from the operation unit 15. In this example, a parameter Gf for changing the peak frequency in the acoustic radiation characteristic, a parameter Gq for changing the sharpness of the peak, and a parameter Gp for adjusting the overall level are set as parameters. Note that these parameters may have predetermined values, or any of the values may be “0”.

The DA conversion unit 130 converts the digital calculation signal Sz output by the signal processing in the DSP into an analog signal and outputs the analog signal. The amplifying unit 140 amplifies the calculation signal Sz output from the DA conversion unit 130 and outputs the amplified signal to the actuator 40 as a drive signal Sp. As a result, the actuator 40 applies a force corresponding to the drive signal Sp to the portion connected to the front plate 11a.
Subsequently, signal processing performed in the DSP 120 will be described.

[Contents of signal processing]
The DSP 120 amplifies the acceleration detection signal Sa according to the parameter Gf. The signal (Gf · Sa) thus obtained is referred to as an acceleration calculation signal Sza. The DSP 120 integrates the acceleration detection signal Sa with respect to time to convert it into a speed signal Sv and performs amplification processing according to the parameter Gq. The signal (Gq · Sv) obtained in this way is referred to as a speed calculation signal Szv. The DSP 120 amplifies the force detection signal Sf according to the parameter Gp. The signal (Gp · Sf) thus obtained is referred to as a force calculation signal Szp. The DSP 120 adds and combines the acceleration calculation signal Sza, the speed calculation signal Szv, and the force calculation signal Szp, and outputs the resultant as the calculation signal Sz. Note that when a DC component is present in the acceleration calculation signal Sza, the speed calculation signal Szv, and the force calculation signal Szp, the DC component may be removed using a DC cut filter or the like.

  By the drive signal Sp obtained by amplifying the calculation signal Sz, the actuator 40 operates and vibrates by applying a force Fa to the front plate 11a. The influence on the vibration will be described separately for each element of the acceleration calculation signal Sza, the speed calculation signal Szv, and the force calculation signal Szp in the force Fa.

[Principle explanation]
FIG. 6 is a diagram illustrating a control model in the control unit 100 according to the embodiment of the present invention. When the vibration plate (mainly the front plate 11a and the bridge 13) that vibrates by the force Fs and the force Fa described above is approximated to a primary mass system, a model shown in FIG. 6 is obtained, and an equation of motion of a spring, mass, damper system (the following equation) (1)). Here, m is mass, c is a damper constant, and k is a spring constant.

  Here, in a state where the force Fa from the actuator 40 is not applied, the resonance frequency and admittance in the modeled portion of the diaphragm are represented by the following equations (2) and (3), respectively. These vibration characteristics are characteristics greatly related to the sound quality as a musical instrument.

  First, the influence of the component of the acceleration calculation signal Sza on the vibration of the diaphragm among the force Fa applied to the diaphragm will be described. In this case, the force Fa is expressed as the following equation (4). Therefore, the above-described formula (1) is expressed as the following formulas (5) and (6), and acts so that the mass m is changed by the force Fa.

  Therefore, the resonance frequency and the admittance are expressed by the following formulas (7) and (8), respectively, and the values change depending on the magnitude of the set parameter Gf.

FIG. 7 is a diagram for explaining an example of the difference in frequency characteristics depending on whether or not the actuator 40 is operated in the control according to the acceleration. FIG. 7 shows an example of the spectrum Soff when the actuator 40 is not operated and the spectrum Son_Ap when the actuator 40 is operated regarding the vibration characteristics, where the horizontal axis indicates the frequency and the vertical axis indicates the level. In this example, it is assumed that Gf is a positive value.
In the example shown in FIG. 7, a characteristic resonance frequency peak of the surface plate 11a appears at 310 Hz in the spectrum Soff. On the other hand, by operating the actuator 40, as shown in the spectrum Son_A, the resonance frequency is lowered to 240 Hz. The amount of change in the resonance frequency is determined by the magnitude of the parameter Gf.

  Here, the frequency of all the peaks does not decrease because the peaks at those frequencies are not caused by the resonance of the front plate 11a, or in the vibration mode in which the peaks resonate at the peak frequency, the actuator 40 of the front plate 11a. This is due to the fact that the amplitude is small in the portion where the force can be applied. Although not shown, if Gf is a negative value, the resonance frequency can be increased.

  Next, the influence of the component of the speed calculation signal Szv on the vibration of the diaphragm among the force Fa applied to the diaphragm will be described. In this case, the force Fa is expressed as the following equation (9). Therefore, the above-described equation (1) is expressed as the following equations (10) and (11), and acts so that the damper constant c is changed by the force Fa.

  Therefore, the admittance is expressed by the following expression (12), and the value changes depending on the size of the set parameter Gq. The resonance frequency is the same as that in Equation (2).

FIG. 8 is a diagram for explaining an example of the difference in frequency characteristics depending on whether or not the actuator 40 is operated in the control according to the speed. FIG. 8 shows the spectrum Soff when the actuator 40 is not operated and the spectra Son_Vp and Son_Vm when the actuator 40 is operated, with the horizontal axis indicating the frequency and the vertical axis indicating the level.
In the example shown in FIG. 8, by operating the actuator 40, when the parameter Gq is a positive value, the peak becomes sharper than the spectrum Soff as shown in the spectrum Son_Vp. On the other hand, when the parameter Gq is a negative value, the peak becomes duller than the spectrum Soff as shown in the spectrum Son_Vm.

  Here, the amount of change in sharpness for all peaks is not the same because each peak is not due to resonance of the surface plate 11a, or in the vibration mode in which resonance occurs at the peak frequency, the actuator of the surface plate 11a. This is due to the fact that the portion where force can be applied from 40 has a small amplitude.

  Next, the influence of the component of the force calculation signal Szp on the vibration of the diaphragm among the force Fa applied to the diaphragm will be described. In this case, the force Fa is expressed as the following equation (13). Therefore, the above-described equation (1) is expressed as the following equations (14) and (15), and acts so that the force Fs from the string 2 is changed by the force Fa.

  Accordingly, the admittance is expressed by the following equation (16), and the value changes depending on the size of the set parameter Gp. The resonance frequency is the same as that in Equation (2).

FIG. 9 is a diagram for explaining an example of the difference in frequency characteristics depending on whether or not the actuator 40 is operated in the control according to the force. FIG. 9 shows the spectrum Soff when the actuator 40 is not operated, and the spectra Son_Fp and Son_Fm when the actuator 40 is operated, with the horizontal axis indicating the frequency and the vertical axis indicating the level.
In the example shown in FIG. 9, by operating the actuator 40, when the parameter Gp is a positive value, the level is generally higher than the spectrum Soff as indicated by the spectrum Son_Fp. On the other hand, when the parameter Gp is a negative value, the level is lower than the spectrum Soff as shown in the spectrum Son_Fm.
Here, the amount of change in level for each frequency component is not the same because of vibration characteristics of the front plate 11a.

  The above is an explanation of the influence of the force Fa of the actuator 40 on the vibration of the front plate 11a divided into the elements of the acceleration calculation signal Sza, the speed calculation signal Szv, and the force calculation signal Szp. As described above, the force Fa applied to the front plate 11a of the actuator 40 is determined by adding and combining the elements of the acceleration calculation signal Sza, the speed calculation signal Szv, and the force calculation signal Szp. Therefore, the force Fa applied from the actuator 40 to the diaphragm is expressed by the following equation (17). The resonance frequency and admittance are expressed by the following equations (18) and (19), respectively.

  In this way, the control unit 100 outputs the drive signal Sp based on the parameters Gf, Gq, and Gp using the acceleration detection signal Sa and the force detection signal Sf, and operates the actuator 40. As a result, not only the vibration based on the vibration transmitted from the string 2 but also the actuator 40 is vibrated, so that the vibration characteristic is substantially changed according to the set parameters. . At this time, since the actuator 40 applies a force to the front plate 11a with the support member 50 as a fulcrum, a state in which the vibration characteristic of the front plate 11a is forcibly changed can be created. Therefore, the guitar 1 according to the embodiment of the present invention can produce sound with varying sound quality by substantially changing the vibration characteristics of the front plate 11a.

<Modification>
As mentioned above, although embodiment of this invention was described, this invention can be implemented in various aspects as follows.
[Modification 1]
In the embodiment described above, one end of the support member 50 is connected to the end block 55 and the other end supports the actuator 40. However, the support member 50 may be configured in another manner. Hereinafter, a plurality of examples will be described.

  FIG. 10 is a front view of the trunk portion 10A in the first modification of the present invention. FIG. 11 is a cross-sectional view of the trunk portion 10A viewed from the direction of arrows XI-XI shown in FIG. In this example, the support member 50 </ b> A has one end connected to the end block 55 and the other end connected to the neck block 56 as in the embodiment. By configuring the support member 50A that supports the actuator 40 in this way, the support member 50A is more difficult to transmit the vibration of the front plate 11a. The above is the description of the first example.

  FIG. 12 is a front view of a trunk portion 10B of another aspect in the first modification of the present invention. 13 is a cross-sectional view of the body portion 10B as seen from the direction of arrows XIII-XIII shown in FIG. In this example, the support member 50B includes a first support member 50B-1, a second support member 50B-2, a third support member 50B-3, a fourth support member 50B-4, and a fifth support member 50B-5. Have. The first support member 50 </ b> B- 1 is a member that supports the actuator 40.

The second support member 50B-2 connects a boundary portion 11ac between the side plate 11c and the front plate 11a and one end of the first support member 50B-1. The third support member 50B-3 connects the boundary portion 11ac between the side plate 11c and the front plate 11a and the other end of the first support member 50B-1. The fourth support member 50B-4 connects the boundary portion 11bc between the side plate 11c and the back plate 11b and one end of the first support member 50B-1. The fifth support member 50B-5 connects the boundary portion 11bc between the side plate 11c and the back plate 11b and the other end of the first support member 50B-1.
The first support member 50B-1 may be configured to be directly connected to the side plate 11c, but the second support member 50B-2, the third support member 50B-3, the fourth support member 50B-4, and the fifth. By being connected to the boundary portions 11ac and 11bc via the support member 50B-5, the vibration of the front plate 11a is less likely to be transmitted. The above is the description of the second example.

  FIG. 14 is a front view of a trunk portion 10C according to another aspect of the first modification of the present invention. FIG. 15 is a cross-sectional view of the trunk portion 10 </ b> C viewed from the direction of arrows XV-XV shown in FIG. 14. In this example, the support member 50C is a block-shaped member and is connected to the back plate 11b. This is suitable when the vibration of the front plate 11a is not easily transmitted to the back plate 11b via the side plate 11c, and when the rigidity of the back plate 11b is higher than that of the front plate 11a.

[Modification 2]
In the embodiment described above, there is one actuator 40, but a plurality of actuators may be provided. In this case, for each actuator 40, the force detection sensor 30, the acceleration sensor 20, and the control unit 100 may be provided. As the support member 50 that supports each actuator 40, one support member 50 may be used in common, or a support member 50 may be provided for each actuator 40. A case where there are two actuators 40, one actuator operates based on the force detection signal Sf, and the other actuator operates based on the acceleration detection signal Sa, is used with reference to FIGS. explain.

  FIG. 16 is a front view of the body portion 10D according to Modification 2 of the present invention. 17 is a cross-sectional view of the body portion 10D viewed from the direction of the arrow XVII-XVII shown in FIG. The bridge 13 is not provided with the acceleration sensor 20, but the acceleration sensor 20D is provided in the central portion (near the sound hole 12) of the front plate 11a. The actuator 40D-1 is supported by a support member 50D-1 connected to the end block 55, similarly to the configuration in the embodiment. On the other hand, the actuator 40D-2 is supported by a support member 50D-2 connected to the neck block 56, and is connected to the surface plate 11a of the portion where the acceleration sensor 20D is provided. The position of the front plate 11a to which the actuator 40D-2 is connected may be a position where the amplitude becomes large in a specific vibration mode in which vibration is to be controlled, and is preferably close to a position where the maximum amplitude is obtained.

  The support member 50D-1 is provided with a control unit 100D-1, and the support member 50D-2 is provided with a control unit 100D-2. The control unit 100D-1 operates the actuator 40D-1 based on the force detection signal Sf, and the control unit 100D-2 is configured to operate the actuator 40D-2 based on the acceleration detection signal Sa.

  FIG. 18 is a block diagram illustrating the configuration of the control units 100D-1 (FIG. 18A) and 100D-2 (FIG. 18B) according to the second modification of the present invention. As shown in FIG. 18A, the control unit 100D-1 is different from the control unit 100 in the embodiment in that the acceleration detection signal Sa from the acceleration sensor 20 is not input. Therefore, in the control unit 100D-1, the DSP 120D-1 performs an operation according to the force Fs to control the operation of the actuator 40D-1. Further, as shown in FIG. 18B, the control unit 100D-2 is different from the control unit 100 in the embodiment in that the force detection signal Sf from the force detection sensor 30 is not input. Accordingly, in the control unit 100D-2, the DSP 120D-2 performs calculation according to the acceleration detected by the acceleration sensor 20D, and controls the operation of the actuator 40D-2.

  It should be noted that the control of the operation of the actuator that applies a force to the front plate 11a has been described with respect to a configuration that includes both what is performed according to the detection result of the force detection sensor and what is performed according to the acceleration sensor. However, the structure performed according to the detection result of either sensor may be sufficient. That is, a configuration in which one of the actuator 40D-1 or the actuator 40D-2 does not exist may be employed. In the case where the actuator 40D-1 does not exist, the force detection sensor 30, the support member 50D-1, and the control unit 100D-1 do not exist. On the other hand, when the actuator 40D-2 does not exist, the acceleration sensor 20D, the support member 50D-2, and the control unit 100D-2 do not exist.

[Modification 3]
In the above-described embodiment, the application example of the present invention in the guitar has been described. However, the present invention may be applied to other musical instruments such as a violin. In addition to the above, applicable musical instruments may be configured to have a diaphragm that radiates sound. For example, in the case of an acoustic piano, the sound board functions as a diaphragm.

  FIG. 19 is a diagram for explaining an application example of the present invention to the grand piano 1E. In FIG. 19, it is a figure which shows the part in which the sound board of the grand piano was provided. The grand piano 1E has a soundboard 11Ea and a straight column 55E connected to the side plate 11Ec. The soundboard 11Ea is connected to a bridge 13E that supports the string 2E.

As shown in FIG. 19A, an acceleration sensor 20E1 is provided in the vicinity of the bridge 13E on the soundboard 11Ea. Further, a force detection sensor 30E is provided in part between the soundboard 11Ea and the bridge 13E. The force detection sensor 30E detects a force from the string 2E to the soundboard 11Ea, that is, a force corresponding to the force Fs in the embodiment. The actuator 40E is supported by a support member 50E connected to the straight column 55E. The actuator 40E is connected to the portion of the soundboard 11Ea to which the bridge 13E (force detection sensor 30E) is connected.
Similar to the control unit 100 in the embodiment, the control unit 100E1 controls the operation of the actuator 40E according to the acceleration detection signal Sa from the acceleration sensor 20E1 and the force detection signal Sf from the force detection sensor 30E. By this control, the actuator 40E applies a force to the soundboard 11Ea with the support member 50E as a fulcrum.

  As another aspect, as shown in FIG. 19 (b), the actuator 40E may be connected to a portion other than the portion where the bridge 13E (force detection sensor 30E) of the soundboard 11Ea is connected. In this case, the acceleration sensor 20E2 may be provided in a portion of the soundboard 11Ea to which the actuator 40E is connected. The control unit 100E2 that controls the actuator 40E controls the operation of the actuator 40E according to the acceleration detection signal Sa from the acceleration sensor 20E2, similarly to the control unit 100D-2 in Modification 2 described above. In addition, although the supporting member 50E was connected to the straight support | pillar 55E, if it is except the sound board 11Ea, you may be connected to another place of the structure which comprises the housing | casing of a musical instrument.

  Further, the present invention is not limited to a stringed instrument having a diaphragm that transmits vibration from a vibrating body such as a string like an acoustic piano, and the present invention is also applied to a body sound instrument in which a striking surface of a cajon or the like functions as a diaphragm. Is possible. A configuration when applied to a cajon will be described with reference to FIGS.

  FIG. 20 is a diagram for explaining an application example of the present invention to the cajon 1F. 21 is a cross-sectional view of the cajon 1F viewed from the direction of the arrow XXI-XXI shown in FIG. The cajon 1F in this example includes a front plate (hitting surface) 11Fa corresponding to the front plate 11a in the embodiment, a back plate (rear surface) 11Fb corresponding to the back plate 11b, and four side plates (2) corresponding to the side plate 11c. 11Fc, and the six plate-like members constitute a rectangular parallelepiped. A sound hole 12F is provided in the back plate 11b. An acceleration sensor 20F is provided on the front plate 11Fa. The actuator 40F is supported by a support member 50F connected to the side plate (bottom surface, seat surface) 11Fc so as to be connected to a portion of the front plate 11Fa where the acceleration sensor 20F is provided. The control unit 100F controls the operation of the actuator 40F according to the acceleration detection signal Sa from the acceleration sensor 20F, similarly to the above-described control unit 100E2.

  As described above, the present invention can be applied not only to a guitar but also to any musical instrument as long as it has a diaphragm that emits sound by vibration of a front plate, a soundboard, and the like.

[Modification 4]
In the above-described embodiment, the DSP 120 may perform correction according to the vibration of the support member 50 when calculating the calculation signal. In this case, the configuration is as follows.

  FIG. 22 is a block diagram illustrating the configuration of the control unit 100G in the fourth modification of the present invention. The control unit 100G includes a correction sensor 150 in addition to the control unit 100 in the embodiment. The correction sensor 150 is attached to the support member 50, detects acceleration generated by vibration of the support member 50, and outputs a correction acceleration detection signal Sc indicating the detection result. The AD conversion unit 110G further converts the correction acceleration detection signal Sc output as an analog signal into a digital signal. The DSP 120G corrects the calculation signal Sz using the correction acceleration detection signal Sc.

  When the support member 50 vibrates, the fulcrum when the actuator 40 applies a force to the front plate 11a vibrates, and thus the force actually applied to the front plate 11a may be different from the force Fa to be applied originally. . For this reason, the DSP 120G performs the correction process so that the force actually applied from the actuator 40 to the front plate 11a approaches the force Fa to be originally applied. Although there are various calculation methods for specific correction processing, any calculation method using the result of detecting the vibration state of the support member 50 may be used.

[Modification 5]
In the above-described embodiment, the acceleration sensor 20 is used. However, the sensor is not limited to the acceleration sensor, and may be any sensor (vibration detection sensor) that detects the vibration state of the front plate 11a, such as a speed sensor or a displacement sensor. A simple sensor may be used. These sensors may use a known configuration that detects speed and displacement by, for example, an optical method, a magnetic method, a sound wave method, and the like. When a speed sensor is used, the acceleration may be calculated by differentiation with respect to speed time. When a displacement sensor is used, the acceleration may be calculated as a second-order derivative with respect to the displacement time, and the speed may be calculated as a first-order derivative with respect to the displacement time. In addition, about a displacement sensor, you may make it detect the variation | change_quantity from the distance used as a reference | standard as a displacement using the distance sensor which detects the distance of the supporting member 50 and the surface board 11a.

[Modification 6]
In the above-described embodiment, the positional relationship between the actuator 40 and the acceleration sensor 20 or the force detection sensor 30 is such that the portion connected to the front plate 11a of the actuator 40 is viewed from the normal direction of the front plate 11a. Although the acceleration sensor 20 and the force detection sensor 30 are attached, the portions are included, but may not be included. As the portion connected to the surface plate 11a of the actuator 40 and the portion to which each sensor is attached are shifted, a force is indirectly applied to the portion to which the sensor is attached. The change is different from the control mode (peak frequency change control, peak sharpness control, level control). Even in such a case, the sound quality different from that of the embodiment can be changed depending on whether the actuator 40 is not operated or operated. As described above, the position of the front plate 11a to which the actuator 40 is connected is preferably a position where the amplitude is increased in a specific vibration mode in which vibration is desired to be controlled, and is preferably close to a position where the maximum amplitude is obtained.

[Modification 7]
In the above-described embodiment, the DSP 120 performs the calculation according to the acceleration and the speed of the front plate 11a, but may perform the calculation according to the displacement. In other words, the calculation may be performed by converting the velocity signal Sv into the displacement signal Sx by integrating the time signal Sv. Then, the calculation result according to the set parameter Gk may be combined with the calculation signal Sz.
When the control according to the displacement is performed, the spring constant k substantially changes. Therefore, similarly to the control according to the acceleration, both the resonance frequency and the admittance can be changed.

DESCRIPTION OF SYMBOLS 1 ... Guitar, 1E ... Grand piano, 1F ... Cajon, 2, 2E ... String, 10, 10A, 10B, 10C, 10D ... Trunk, 11a, 11Fa ... Front board, 11Ea ... Sound board, 11b, 11Fb ... Back board 11c, 11Ec, 11Fc ... side plate, 12, 12F ... sound hole, 13, 13E ... bridge, 14 ... saddle, 15 ... operation part, 20, 20D, 20E1, 20E2, 20F ... acceleration sensor, 30, 30E ... force detection Sensor, 40, 40D-1, 40D-2, 40E, 40F ... Actuator, 50, 50A, 50B, 50C, 50D-1, 50D-2, 50E, 50F ... Support member, 55 ... End block, 55E ... Straight support 56 ... Neck block, 100, 100D-1, 100D-2, 100E1, 100E2, 100F, 100G ... Control unit, 110, 110D 1,110D-2,110G ... AD conversion unit, 120,120D-1,120D-2,120G ... DSP, 130 ... DA conversion section, 140 ... amplifier unit

Claims (8)

A vibrating string,
A string support portion for supporting the string;
A diaphragm that is connected to the string support portion, and vibrations of the string are transmitted through the string support portion;
A structure that supports the diaphragm;
A force detection sensor that detects a force received from the diaphragm and the string and outputs a force detection signal indicating a detection result;
An actuator that operates to vibrate by applying force to the diaphragm;
A member connected to the structure and having a higher rigidity than the diaphragm, and a support member that supports the actuator so that the actuator is connected to the diaphragm;
A musical instrument comprising: a control unit that controls the operation of the actuator so that a force according to the force detection signal is applied to a portion of the diaphragm to which the string support unit is connected. The musical instrument according to claim 1, wherein a portion of the diaphragm connected to the actuator is a portion connected to the string support portion. A second actuator that operates to vibrate by applying force to the diaphragm;
A vibration detection sensor that detects a vibration state of a part of the diaphragm that is a physical quantity different from the force detected by the force detection sensor and outputs a vibration detection signal indicating a detection result;
The said control part controls operation | movement of a said 2nd actuator so that the force according to the said vibration detection signal is added to a part of said diaphragm. The Claim 1 or Claim 2 characterized by the above-mentioned. Musical instruments. A part of the diaphragm is a part connected to the second actuator of the diaphragm.
The musical instrument according to claim 3.
A second vibration detection sensor that detects a vibration state of the support member and outputs a second vibration detection signal indicating a detection result;
The control unit controls the operation of the second actuator so that a force corresponding to the vibration detection signal and the second vibration detection signal is applied to a part of the diaphragm.
The musical instrument according to claim 3 or 4, characterized by the above. A diaphragm,
A structure that supports the diaphragm;
A vibration detection sensor that detects a vibration state of a part of the diaphragm and outputs a vibration detection signal indicating a detection result;
An actuator that operates to vibrate by applying force to the diaphragm;
A member connected to the structure and having a higher rigidity than the diaphragm, and a support member that supports the actuator so that the actuator is connected to the diaphragm;
A musical instrument comprising: a control unit that controls the operation of the actuator such that a force corresponding to the vibration detection signal is applied to a part of the diaphragm. The musical instrument according to claim 6 , wherein a part of the diaphragm is a part connected to the actuator of the diaphragm. A second vibration detection sensor that detects a vibration state of the support member and outputs a second vibration detection signal indicating a detection result;
Wherein the control unit, said response to the vibration detection signal and the second vibration detection signal force, the to be added to a portion of the diaphragm, according to claim 6 or, characterized in that for controlling the operation of said actuator The musical instrument according to claim 7 .

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