JP2012118335A - Musical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a musical instrument that can generate sound quality different from that in consonance with a shape of a body thereof, while keeping resonance of the body which receives vibration of a vibrating body.SOLUTION: A guitar comprises: a body 10 having a sound hole 12; a converting part 20 for converting strings' vibration transmitted to the body 10 into electric signals for output; a signal processing part 100 for applying signal processing to the output electric signals and changing frequency characteristics of the electric signals; and a speaker 50 that is placed so that a vibration surface is included in an internal space BS of the body 10, converts the electric signals applied with the signal processing into sound, and plays sound to the outside of the body 10 through the sound hole 12. As a result, the guitar can generate sound having quality resembling the resonance characteristics of a body which is larger than the actual body 10.

Description

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

  In a stringed instrument such as a guitar, the vibration of the string is transmitted to the trunk. The transmitted vibration resonates in the internal space of the torso, and the guitar produces sound with a sound quality corresponding to the shape of the torso. If the torso is small, the performer can easily carry the guitar, but the volume of the torso becomes small, so the volume of the low range is reduced. In this way, the phenomenon that the volume of the low frequency is insufficient is not limited to the case where the volume of the body is reduced, but the vibration of the picked string is forcibly transmitted to the body using an exciter to increase the volume. Even in such a configuration, there is a problem. In Patent Document 1 using such a configuration, it is disclosed that a speaker for enhancing the volume of a low frequency band is fitted into the back plate of the body of the guitar.

JP 2002-539479 A

In the technique disclosed in Patent Document 1, sound from a speaker fitted in the back plate is output in the player direction on the back plate side of the trunk. This sound is an electrical signal that picks up the vibration of the string and is output as a sound, so the vibration of the string is converted into sound as it is, and the sound as if playing an electric guitar is output from the speaker. Is done. In addition, the sound generated by the vibration of the front plate can be heard from the sound hole of the torso, while the sound from the speaker can be heard from the back plate side of the torso, and there is little sense of unity of each sound. . Thus, even if a speaker is provided, the sound quality when the trunk is large is greatly different. Furthermore, since this speaker is provided on the back plate of the trunk, it can be visually recognized from the outside. Therefore, it has an aspect that it is not desirable as an appearance of an acoustic guitar.
The present invention has been made in view of the above circumstances, and provides a musical instrument that produces a sound quality different from the sound quality according to the shape of the body while leaving the resonance of the body to which the vibration of the vibrating body is transmitted. The purpose is to do.

  In order to solve the above-described problems, the present invention has a sound hole and an internal space, and a trunk portion to which the vibration of the vibrating body is transmitted, and the vibration transmitted to the trunk portion is converted into an electrical signal and output. A conversion unit; a signal processing unit configured to perform signal processing on the output electric signal to change a frequency characteristic of the electric signal; and a vibration surface, so that the vibration surface is included in the internal space. And a speaker that converts the electric signal subjected to the signal processing into sound by vibration of the vibration surface and emits the sound to the outside of the trunk through the sound hole. To provide a musical instrument.

  Moreover, in another preferable aspect, the speaker is arranged at a position sandwiched between a front plate constituting the trunk portion provided with the sound hole and a back plate constituting the trunk portion. To do.

  In another preferred aspect, the signal processing includes processing for relatively increasing the output level on the low frequency side of the output electric signal as compared with that on the high frequency side.

  Moreover, in another preferable aspect, it further has an enclosure provided so that one surface in the said vibration surface may be enclosed.

  In another preferred embodiment, the enclosure has a port.

  In another preferred aspect, the speaker is arranged such that the sound hole is located in the sound axis direction of the speaker.

  According to the present invention, it is possible to provide a musical instrument that generates sound with a sound quality different from the sound quality corresponding to the shape of the body while leaving the resonance of the body to which the vibration of the vibrating body is transmitted.

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 block diagram explaining the structure of the signal processing part in embodiment of this invention. It is a figure explaining the difference in the acoustic radiation characteristic by the difference in the magnitude | size of a trunk | drum. It is a figure explaining the difference in the acoustic radiation characteristic by the presence or absence of the sound emission from a speaker in the trunk | drum in embodiment of this invention. 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 VIII-VIII direction shown in FIG. It is sectional drawing of the state in which the sound hole adapter was attached to the trunk | drum of the modification 1. It is a figure explaining the difference in the acoustic radiation characteristic by the presence or absence of a sound hole adapter. FIG. 10 is a cross-sectional view of a state in which a sound hole adapter having a shape different from the shape in FIG. It is a figure explaining the structure of the violin in the modification 3 of this invention. It is sectional drawing of the trunk | drum seen from the arrow XIII-XIII direction shown in FIG. It is explanatory drawing about the case where the speaker and enclosure are attached to the trunk | drum in the modification 4, and the case where it removes.

<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 to the trunk portion 10 through the saddle 14 that contacts the string 2 and the bridge 13 that supports the saddle 14. An operation unit 30 is provided on the side plate 11 c of the body unit 10. The operation unit 30 has an operation panel provided with a rotary switch, operation buttons, and the like. When an operation by the user is accepted, the operation unit 30 outputs information indicating the operation content. The operation unit 30 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.

[Configuration of trunk 10]
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 drawings shown below, description of the strings 2, fingerboards, and the like, which are other components of the guitar 1, is omitted. Further, in order to make it easy to understand the positional relationship of the speaker 50 and the like described below, the description of the sounding bar provided inside the trunk portion 10 is also omitted.

  The trunk | drum 10 has internal space BS enclosed by the front board 11a, the back board 11b, and the side board 11c. A conversion unit 20 is provided in a portion facing the bridge 13 and the saddle 14 on the inner space BS side of the front plate 11a. The conversion unit 20 includes a contact-type piezo pickup and converts the vibration of the string 2 transmitted to the body unit 10 into an electric signal (hereinafter referred to as an audio signal Sa) and outputs the electric signal. Note that the piezo pickup may have an in-bridge configuration provided at a connection portion between the saddle 14 and the bridge 13.

  In the internal space BS of the trunk portion 10, a signal processing unit 100 that supplies an audio signal Sb obtained by performing signal processing on the audio signal Sa output from the conversion unit 20 to the speaker 50, and the supplied audio A speaker 50 that converts the signal Sb into sound by vibration of the vibration surface and emits the sound is provided. The sound emitted from the speaker 50 is generated by the vibration of the vibration surface arranged at a position included in the internal space BS, and is transmitted to the outside of the trunk portion 10 through the sound hole 12. Note that the signal processing unit 100 may be provided not on the internal space BS of the body 10 but on the outside of the body 10.

  The speaker 50 is disposed at a position sandwiched between the front plate 11a and the back plate 11b. By being arranged at this position, the speaker 50 is not visually recognized from the sound hole 12 when viewed from the front direction of the trunk 10, and is difficult to see from the outside of the trunk 10. The direction of the speaker 50 is determined so that the surface (corresponding to the vibration surface) having the sound axis direction AX of the speaker 50 as a normal line is inclined with respect to the surface of the front plate 11a. In this example, the sound axis direction AX of the speaker 50 is configured to be in the direction of the sound hole 12. When the speaker 50 is arranged in such a direction, most of the sound emitted from the speaker 50 reaches the sound hole 12, so that the high frequency characteristics can be improved. Note that the sound axis direction AX of the speaker 50 does not have to face the direction of the sound hole 12.

An enclosure 55 is provided on the back side of the speaker 50. In this example, the enclosure 55 and the back plate 11b constitute a space ES. Thus, one surface of the vibration surface of the speaker 50 is surrounded by the enclosure 55 and faces the space ES side, and the other surface faces the outside of the space ES. The enclosure 55 may be configured with a hole or a duct-shaped port. The exit portion of the hole may be present inside the body 10, that is, in the internal space BS, or may be present outside the body 10.
The enclosure 55 is not necessarily provided. However, when the front side of the speaker 50 has a positive pressure, the back side has a negative pressure, and the sound pressure is canceled in the internal space BS of the trunk portion 10. May end up. Therefore, it is desirable that such an enclosure 55 is provided so that sound is efficiently emitted from the sound hole 12.

  It is assumed that the sounding rod, not shown, is provided in the same configuration as that of a general guitar, but may be provided so as to avoid the positions of the speaker 50 and the enclosure 55, or the speaker 50. And the enclosure 55 may be configured to avoid a sounding bar. Further, if the configuration of the enclosure 55 can be used as a sounding bar, the number of sounding bars can be reduced as compared with the case where the enclosure 55 does not exist.

[Configuration of Signal Processing Unit 100]
FIG. 4 is a block diagram illustrating the configuration of the signal processing unit 100 according to the embodiment of the present invention. The signal processing 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 converts the audio signal Sa that is an analog signal input from the conversion unit 20 into a digital signal.

  The DSP 120 subjects the audio signal Sa converted to a digital signal to signal processing for relatively increasing the output level on the low frequency side using a parametric equalizer, a graphic equalizer, and the like, and outputs the result. In this example, the DSP 120 is realized by an IIR (Infinite impulse response) filter having a frequency characteristic that relatively increases the output level on the low frequency side as compared with the high frequency side. The range of the frequency indicated by the low frequency side is determined according to the volume of the internal space BS of the trunk portion 10, but in this example, it is generally in the range of 50 Hz to 180 Hz. This upper limit frequency is determined according to f1 in the acoustic radiation characteristics described later.

The DA converter 130 converts a digital signal that has been subjected to signal processing in the DSP into an analog signal and outputs the analog signal. The amplification unit 140 amplifies the signal output from the DA conversion unit 130 and outputs the amplified signal to the speaker 50.
Note that the signal processing unit 100 may change the content of signal processing performed in the DSP 120, the amplification factor in the amplification unit 140, and the like in accordance with the operation signal output from the operation unit 30. The above is the description of the configuration of the trunk portion 10 in the guitar 1.
Subsequently, the difference in sound quality caused by the difference in the size of the trunk in the guitar will be described using the acoustic radiation characteristics.

[Comparison of acoustic radiation characteristics]
FIG. 5 is a diagram for explaining a difference in acoustic radiation characteristics due to a difference in size of the body portion. The acoustic radiation characteristics shown in FIG. 5 are described with the horizontal axis representing frequency and the vertical axis representing level. The spectrum SB indicates the acoustic radiation characteristics of a guitar having a small trunk (corresponding to the size of the trunk 10 in the present embodiment), and the spectrum LB indicates the acoustic characteristics of a guitar having a large trunk.
The spectrum SB has two peaks (f1S, f2S) characteristic of the low frequency band. Similarly, the spectrum LB has two peaks (f1L, f2L). As shown in FIG. 5, it can be seen that the spectrum SB has a lower sound pressure than the spectrum LB in the low frequency band side, particularly in the frequency band lower than f1S. This is a phenomenon that occurs due to the small volume of the internal space in a small body.

FIG. 6 is a diagram for explaining a difference in acoustic radiation characteristics depending on presence / absence of sound emission from the speaker 50 in the trunk portion 10 according to the embodiment of the present invention. The acoustic radiation characteristics shown in FIG. 6 are described with the horizontal axis as frequency and the vertical axis as level. The spectrum Soff indicates the acoustic radiation characteristic when the speaker 50 does not emit sound in the trunk section 10, and the spectrum Son indicates the acoustic radiation characteristic when the speaker 50 emits sound.
The spectrum Soff has peaks f1 and f2. The frequency of the peak f1 is slightly higher than the peak f1S in the spectrum SB described above. Further, the spectrum Soff has a lower level in the low frequency band than the spectrum SB. This is because the volume of the portion connected to the sound hole 12 in the internal space BS of the trunk portion 10 is reduced by an amount corresponding to the volume of the space ES formed by the enclosure 55.

When the sound is emitted from the speaker 50, as shown in the spectrum Son, the level of the frequency band lower than the peak f1 becomes high, while the frequency band higher than the peak f1 does not change much. The increase in sound pressure in the low frequency band is an effect obtained by the influence of signal processing in the signal processing unit 100. On the other hand, there is little change in the high frequency band because the speaker 50 emits sound in the internal space BS of the trunk section 10 in addition to the influence of the signal processing section 100 and is affected by the resonance characteristics of the trunk section 10. by.
As described above, the guitar 1 according to the embodiment of the present invention can generate sound with a sound quality close to that of a guitar using a trunk having a volume larger than the trunk 10 due to an increase in sound pressure in a frequency band lower than the peak f1. it can. Moreover, in this guitar 1, since the change of the acoustic radiation characteristic in a frequency band higher than the peak f1 is small, it is possible to produce sound with a sound quality that leaves a sense of resonance of the trunk portion 10.

<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, the direction of the speaker 50 is configured such that the vibration surface of the speaker 50 is inclined with respect to the surface of the surface plate 11 a, and the sound axis direction AX of the speaker 50 is in the direction of the sound hole 12. However, it is not necessarily limited to this configuration.

  FIG. 7 is a front view of the trunk portion 10A in the first modification of the present invention. FIG. 8 is a cross-sectional view of the trunk portion 10A viewed from the direction of arrows VIII-VIII shown in FIG. 7 and FIG. 8, illustration of a part of the configuration described in the embodiment such as the signal processing unit 100 is omitted (the same applies to the following drawings). The speaker 50 </ b> A according to Modification 1 is configured so that the surface of the front plate 11 a and the vibration surface of the speaker 50 are parallel to each other. Therefore, the sound axis direction AX of the speaker 50 does not face the direction of the sound hole 12. With this configuration, the diameter of the speaker 50 can be increased regardless of the distance between the front plate 11a and the back plate 11Ab, and the low frequency characteristics can be improved. Therefore, the diameter of the speaker 50A arranged in this way is desirably longer than the distance between the front plate 11a and the back plate 11Ab.

  In the first modification, a part of the enclosure 55A protrudes outward from a portion opened in the back plate 11Ab. Therefore, the shape of the trunk portion 10A of the first modification is a shape having the protruding portion. The protruding portion is provided with a hole 57A. The hole 57A may be constituted by a port or may not exist. Moreover, the enclosure 55A does not need to have the part which protruded outside 10 A of trunk | drums similarly to the enclosure 55 in embodiment. In this case, the shape of the trunk portion 10A is the same as the shape of the trunk portion 10A in the embodiment.

  Moreover, the direction of the speaker 50 may face another direction. For example, the vibration surface of the speaker 50 may be in a direction intersecting with the surface of the front plate 11a at a right angle, or the sound axis direction AX of the speaker 50 may be directed to the back plate 11b.

[Modification 2]
In the embodiment described above and Modification 1, the hole diameter of the sound hole 12 may be reduced. For example, you may provide the sound hole adapter which attaches to the sound hole 12 in the trunk | drum 10, 10A, and makes a hole diameter small. Hereinafter, the case where the sound hole adapter is attached to the trunk portion 10A in the first modification will be described.

  FIG. 9 is a cross-sectional view of a state in which the sound hole adapter 92 is attached to the body portion 10A of the first modification. As shown in FIG. 9, the sound hole adapter 92 is attached to the sound hole 12 from the outside of the body part 10A, thereby reducing the area of the hole that leads from the internal space BS of the body part 10A to the space outside the body part 10A. To do.

FIG. 10 is a diagram for explaining a difference in acoustic radiation characteristics depending on the presence or absence of the sound hole adapter 92. In the acoustic radiation characteristics shown in FIG. 10, the horizontal axis represents frequency and the vertical axis represents level. The spectrum LS shows the acoustic radiation characteristic in the trunk portion 10A to which the sound hole adapter 92 is not attached, and the spectrum SS shows the acoustic radiation characteristic in the trunk portion 10A to which the sound hole adapter 92 is attached. As shown in FIG. 10, when the area of the sound hole 12 is reduced, the resonance frequency of the Helmholtz resonance can be lowered. Thereby, the frequency of each peak may be lowered so as to approximate the acoustic radiation characteristic in a large trunk.
Further, instead of reducing the area of the hole of the sound hole 12 or reducing it, the sound hole 12 may be configured as a duct-like port.

FIG. 11 is a cross-sectional view of a state in which a sound hole adapter 92A having a shape different from the shape in FIG. As shown in FIG. 11, the sound hole adapter 92 </ b> A is configured in a duct shape, and the resonance frequency can be lowered by the effect that the air spring in the hole portion becomes soft. In this manner, as shown in FIG. 10, the acoustic radiation characteristics in a large body may be approximated.
In the above example, the shape of the hole of the sound hole 12 is changed by attaching the sound hole adapters 92 and 92A. However, the sound hole 12 having the same configuration as that of the sound hole 12 without being attached. You may comprise the shape of the surface board 11a so that it may become.

[Modification 3]
In the above-described embodiment, the guitar 1 has been described as an example of a musical instrument, but a musical instrument other than a guitar may be used. For example, a musical instrument such as a violin may be used. An example of the configuration when a speaker is provided on the body of the violin will be described.

FIG. 12 is a diagram illustrating the configuration of the violin 1B according to the third 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 FIG. 12, the vicinity of the speaker 50B is illustrated so that the internal structure can be seen by a broken line. In the figure shown below, description is abbreviate | omitted about the bus-bar, soul pillar, etc. which are provided in the inside of the trunk | drum 10 in violin 1B.
The body 10B of the violin 1B has an f-shaped hole 12B corresponding to the sound hole 12 in the embodiment. The bridge 13 </ b> B transmits the vibration of the string 2 </ b> B to the trunk portion 10. The vibration of the string is converted into an electric signal by the conversion unit 20B provided on the inner space side of the front plate 11Ba.

  Similar to the embodiment, a speaker 50B and an enclosure 55B are provided in the internal space of the body portion 10B. The speaker 50B is provided at a position sandwiched between the front plate 11Ba and the back plate 11Bb, and is difficult to see from the f-shaped hole 12B. In the cross-sectional view as shown in FIG. 13, the sound axis direction of the speaker 50B faces the direction of the f-shaped hole 12B, but as shown in FIG. 12, the speaker 50B is along the string 2B of the trunk portion 10B. In reality, the sound axis direction of the speaker 50B is directed to the front plate 11Ba at the center of the two f-shaped holes 12B. Note that the sound axis direction of the speaker 50B may be directed to one of the f-shaped holes 12B. Also, two speakers 50B are provided so that the sound axis direction of one speaker 50B faces the one f-shaped hole 12B, and the sound axis direction of the other speaker 50B faces the other f-shaped hole 12B. Also good. As shown in the first modification, the speaker 50B may be arranged such that its vibration surface is parallel to the surface of the surface plate 11Ba.

  Further, as shown above, an example of a musical instrument is not limited to a stringed instrument, and may be anything that has a vibrating body and a body having an opening corresponding to a sound hole through which vibrations of the vibrating body are transmitted. . For example, the present invention can also be applied to percussion instruments (membrane musical instruments) having a film as a vibrating body, such as conga, bongo, bass drum, timpani. In general, many musical instruments having a torso that pronounces a large low range have a large torso, but the torso can be made smaller by using the configuration of the present invention.

[Modification 4]
In the embodiment described above, the speaker 50 and the enclosure 55 may be configured to be detachable from the trunk portion 10. An example of this case will be described with reference to FIG.

FIG. 14 is an explanatory diagram of the case where the speaker 50C and the enclosure 55C are attached to and removed from the body 10C according to the fourth modification. 14A shows a state where the speaker 50C and the enclosure 55C are attached, FIG. 14B shows a state where the speaker 50C and the enclosure 55C have been removed, and FIG. 14C shows a lid. It is a figure which shows the state in which part 11Cd was attached to back plate 11Cb.
The enclosure 55C and the cover plate 11Cd are provided so as to be detachable from the back plate 11Cb by an attaching / detaching portion 60C constituted by screws or the like. What is necessary is just to comprise so that the signal path | route of the conversion part 20 and the speaker 50C can be connected or disconnected by the connector etc. which are not shown in figure. Note that the signal processing unit 100 (not shown) may be attached and detached together with the enclosure 55C.
With this configuration, when the performer wants to perform with an emphasis on the low range, the speaker 50C and the enclosure 55C are attached to the trunk portion 10C. What is necessary is just to perform as a structure which attached 11 Cd of cover plates.

[Modification 5]
In the above-described embodiment, the speaker 50 is disposed at a position sandwiched between the front plate 11a and the back plate 11b, and is difficult to see from the sound hole 12, but the sound hole 12 portion and the back plate 11b are arranged. It may be arranged at a position to be sandwiched and be in a state where it can be easily seen from the sound hole 12.

[Modification 6]
In the above-described embodiment, the signal processing in the DSP 120 is signal processing that relatively increases the output level on the low frequency side, but any signal processing that changes the frequency characteristics of the audio signal Sa can be used. It may be signal processing. For example, there is signal processing for increasing a specific frequency band as compared with other frequency bands. The specific frequency band may be a frequency band higher than f1 in the acoustic radiation characteristic. In this way, it is possible to produce sound with a sound quality to which a glittering sound is added according to the frequency band to be increased. The specific frequency band may be divided into a plurality of bands.

DESCRIPTION OF SYMBOLS 1 ... Guitar, 1B ... Violin, 2, 2B ... String, 10, 10A, 10B, 10C ... Trunk, 11a, 11Ba ... Front plate, 11b, 11Ab, 11Bb, 11Cb ... Back plate, 11c ... Side plate, 11Cd ... Lid Plate, 12 ... Sound hole, 12B ... f-shaped hole, 13, 13B ... Bridge, 14 ... Saddle, 20, 20B ... Conversion part, 30 ... Operation part, 50, 50A, 50B, 50C ... Speaker, 55, 55A, 55B , 55C ... enclosure, 57A ... hole, 60C ... detachable part, 92, 92A ... sound hole adapter, 100 ... signal processing part, 110 ... AD converter, 120 ... DSP, 130 ... DA converter, 140 ... amplifier

Claims (6)

A body portion having a sound hole and an internal space, to which the vibration of the vibrating body is transmitted;
Conversion means for converting the vibration transmitted to the body part into an electrical signal and outputting the electrical signal;
Signal processing means for performing signal processing on the output electrical signal to change a frequency characteristic of the electrical signal;
The vibration surface is arranged so that the vibration surface is included in the internal space, the electric signal subjected to the signal processing is converted into sound by vibration of the vibration surface, and the sound signal is transmitted through the sound hole. A musical instrument comprising: a speaker that emits sound outside the trunk. 2. The musical instrument according to claim 1, wherein the speaker is disposed at a position sandwiched between a front plate constituting the trunk portion provided with the sound hole and a back plate constituting the trunk portion. . The musical instrument according to claim 1, wherein the signal processing includes a process of relatively increasing an output level on a low frequency side in the output electric signal as compared with a high frequency side. The musical instrument according to any one of claims 1 to 3, further comprising an enclosure provided so as to surround one surface of the vibration surface. The musical instrument according to claim 4, wherein the enclosure has a port. The musical instrument according to any one of claims 1 to 5, wherein the speaker is arranged so that the sound hole is located in a sound axis direction of the speaker.