Musical instrument soundboard and stringed musical instrument

Abstract

A musical instrument soundboard 1 according to one embodiment of the present disclosure comprises: a first plate material 11; a pair of second plate materials 12 disposed so as to face each other with the first plate material 11 interposed therebetween; and a pair of third plate materials 13 disposed so as to face each other with the pair of second plate materials 12 interposed therebetween. The third plate material 13 has stronger anisotropy than the first plate material 11 and the second plate material 12 with respect to a loss tangent. Where a direction which is parallel to the surface of the third plate material 13 and in which the loss tangent of the third plate material 13 is minimized is defined as an X direction, the loss tangent of the first plate material 11 in the X direction is larger than any of the loss tangent of the second plate material in the X direction 12 and the loss tangent of the third plate material 13 in the X direction.

Description

Musical soundboards and string instruments

[0001] The present disclosure relates to musical instrument soundboards and stringed instruments.

[0002] Stringed instruments and other musical instruments use a diaphragm, which propagates vibrations. This diaphragm is made of wood, for example. It is known that the timbre of a musical instrument (sound quality, volume, sustain, etc.) is highly dependent on the quality of the wood.

[0003] If the board is made only of natural wood, it will be expensive and will require processes such as material selection, cutting, joining, etc. Even if the same type of natural wood is used, it will be difficult to obtain boards of consistent quality. For this reason, a soundboard for a musical instrument has been proposed that is easy to manufacture and can produce sufficient and good sounds from low to high frequencies (see Japanese Patent Laid-Open Publication No. 60-57894).

[0004] This soundboard for musical instruments has a core material made of a material with a high elastic modulus and low shear loss between the front and back panels made of wood veneer, so that it can produce a well-balanced sound from low to high frequencies.

[0005] Japanese Patent Application Publication No. 60-57894

[0006] For example, natural rosewood, especially Brazilian rosewood (Jacaranda), is said to produce a good tone, but the above-mentioned instrument soundboard, although excellent in sound production, does not reach that level.

[0007] The present disclosure has been made in light of the above circumstances, and aims to provide a musical instrument soundboard that can be manufactured stably and has excellent tone, and a stringed instrument that uses this musical instrument soundboard.

[0008] (1) A soundboard for a musical instrument according to one aspect of the present disclosure comprises a first plate, a pair of second plates arranged opposite each other with the first plate in between, and a pair of third plates arranged opposite each other with the pair of second plates in between, wherein the third plate has stronger anisotropy with respect to loss tangent than the first plate and the second plate, and when the X direction is defined as the direction parallel to the surface of the third plate and in which the loss tangent of the third plate is smallest, the X direction loss tangent of the first plate is greater than both the X direction loss tangent of the second plate and the X direction loss tangent of the third plate.

[0009] (2) In the soundboard for musical instruments of (1), the loss tangent in the X direction of the first plate material is 3×10 －３ Above 60 x 10 －３ The loss tangent in the X direction of the second plate material is 0.2 × 10 or less. －３ 10 x 10 or more －３ The loss tangent in the X direction of the third plate material is 0.5 × 10 or less. －３ 4 x 10 or more －３ It would be better if it was below.

[0010] (3) In the soundboard for musical instruments of (1) or (2), when a direction parallel to the surface of the third plate and perpendicular to the X direction of the previous device is defined as a Y direction, the loss tangent of the first plate in the Y direction is 3×10 －３ Above 60 x 10 －３ The loss tangent in the Y direction of the second plate material is 0.2 × 10 or less. －３ 10 x 10 or more －３ The loss tangent in the Y direction of the third plate material is 5 × 10 or less. －３ Above 40 x 10 －３ It would be better if it was below.

[0011] (4) In any of the musical instrument soundboards (1) to (3), the ratio of the loss tangent in the X direction to the Y direction of the first plate material is preferably 0.5 or more and 1 or less, the ratio of the loss tangent in the X direction to the Y direction of the second plate material is preferably 0.7 or more and 1 or less, and the ratio of the loss tangent in the X direction to the Y direction of the third plate material is preferably 0.04 or more and 0.43 or less.

[0012] (5) In the musical instrument soundboard of any one of (1) to (4) above, the third plate material may have a stronger anisotropy in elastic modulus than the second plate material.

[0013] (6) In any of the soundboards for musical instruments described in (1) to (5), the raw material of the first plate material may be high-elastic fiber or wood, the raw material of the second plate material may be metal, and the raw material of the third plate material may be carbon, glass fiber, or basalt fiber.

[0014] (7) In any of the soundboards for musical instruments described in (1) to (6), the space between the pair of third plates may be configured symmetrically in the thickness direction around a bisecting plane that divides the distance between the pair of third plates in half.

[0015] (8) A stringed instrument according to another aspect of the present disclosure includes a soundboard for a musical instrument according to any one of (1) to (7).

[0016] In this disclosure, the comparison of "anisotropy with respect to loss tangent" is expressed as the ratio of the loss tangent in the X direction of the plate to the loss tangent in the Y direction on the surface of the plate, and when this ratio is close to 0, the anisotropy is judged to be strong, and when this ratio is close to 1, the anisotropy is judged to be weak. Furthermore, the comparison of "anisotropy with respect to elastic modulus" is judged by replacing the loss tangent with the elastic modulus in the comparison of "anisotropy with respect to loss tangent" described above. As described above, the X and Y directions are determined by the characteristics of the loss tangent of the third plate, and the X and Y directions determined by the loss tangent of the third plate are also applied to the first and second plate, as well as to the elastic modulus.

[0017] "Raw material of the board" refers to the main material that determines the characteristics of the board, and excludes binders such as resins that are used to fix or strengthen the material. The raw material typically accounts for 40% or more by volume of the board, and preferably 55% or more by volume. The raw material may also include multiple types of materials. "High-elasticity fiber" refers to fibers that, when processed into boards, have an elastic modulus of 40 GPa or more.

[0018] After extensive research into the timbre of musical instrument soundboards, the inventors discovered that the timbre of a stringed instrument is primarily determined by the magnitude and anisotropy of the loss tangent, and that increasing the loss tangent on the inner side of the soundboard brings the timbre closer to that of natural wood. Therefore, this musical instrument soundboard is configured so that the X-direction loss tangent of the first plate member located at the center of the thickness direction is greater than the X-direction loss tangents of the second and third plates. Furthermore, in this musical instrument soundboard, the third plate member has a stronger anisotropy of the loss tangent than the first and second plates. In other words, since the magnitudes of the loss tangent and their anisotropy differ among the plates, controlling the thicknesses of the first, second, and third plates allows for independent control of the loss tangent and anisotropy of the entire musical instrument soundboard. Therefore, the loss tangent and anisotropy of the entire musical instrument soundboard can be set to desired values ​​to achieve a desired timbre, making it easy to reproduce an excellent timbre. Furthermore, the soundboard for musical instruments can be constructed by controlling the loss tangent and its anisotropy, so that the same soundboard can be manufactured stably.

[0019] Fig. 1 is a schematic cross-sectional view showing the configuration of a board material of a musical instrument soundboard according to one embodiment of the present disclosure. Fig. 2 is a schematic front perspective view showing a stringed instrument including the musical instrument soundboard of Fig. 1. Fig. 3 is a schematic rear perspective view showing the stringed instrument of Fig. 2. Fig. 4 is a graph showing the frequency characteristics of the tone of the guitar of Example No. 1. Fig. 5 is a graph showing the frequency characteristics of the tone of the guitar of Example No. 2.

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that with respect to the numerical values ​​described in this specification, only one of the stated upper and lower limits may be adopted, or any combination of the upper and lower limits may be used.

[0021] 1 comprises a first plate 11, a pair of second plates 12 arranged opposite each other with the first plate 11 in between, and a pair of third plates 13 arranged opposite each other with the pair of second plates 12 in between. The musical instrument soundboard 1 also comprises a decorative panel 14 on the outside of one of the third plates 13.

[0022] <First Plate Material> The first plate material 11 is formed in a plate shape, and its raw material is preferably high-elasticity fiber or wood, more preferably high-elasticity fiber. Note that wood can be used alone as the first plate material 11, or wood impregnated with resin can also be used. High-elasticity fiber is generally used for the first plate material 11 as a fiber-reinforced plastic in which fibers are dispersed in resin.

[0023] Examples of the highly elastic fibers include polyarylate fibers, aramid fibers, polyparaphenylene benzobisoxazole fibers, liquid crystal polyester fibers, ultra-high molecular weight polyethylene fibers, and combinations thereof. Examples of the wood include softwoods such as spruce and hardwoods such as rosewood, maple, and hornbeam.

[0024] The first plate material 11 may be a plywood made by laminating multiple layers made of different types of raw materials. By using plywood as the first plate material 11, it is easy to control the loss tangent, elastic modulus, and anisotropy thereof, which will be described later, to desired values.

[0025] Furthermore, when the raw material of the first board 11 is high-elasticity fiber or wood, the first board 11 may contain other layers made of materials other than the high-elasticity fiber and wood, but the average thickness of the other layers relative to the average thickness of the first board 11 is preferably 50% or less, more preferably 30% or less. Here, "average thickness" refers to the average value of thicknesses measured at any 10 points. Unless otherwise specified, the same applies to "average" of other quantities in this specification.

[0026] Examples of raw materials for the other layers include foaming agents for weight reduction, and glass or carbon for strength improvement. The other layers may be composed of multiple layers made of different raw materials. When the first plate material 11 includes the other layer, from the perspective of tone quality, it is preferable to arrange a pair of high-elasticity fiber layers or wood layers facing each other, with the other layer in between, as the center.

[0027] When the raw material for the first board 11 is wood, it is preferable to set the plane (LR plane; straight grain plane) including the R direction (radial direction of the wood), which is the direction in which the loss tangent is maximized, and the L direction (fiber direction of the wood; height direction of the wood) as the face of the first board 11, and the T direction (tangential direction of the wood) as the thickness direction of the first board 11. By allocating the directions in this manner, the loss tangent and its anisotropy required for the first board 11 can be easily obtained. In this case, it is preferable that the R direction of the wood coincides with the Y direction of the third board, and the L direction of the wood coincides with the X direction of the third board. By aligning the directions in this manner, it is easier to set the loss tangent and its anisotropy of the entire musical instrument soundboard to achieve the desired tone.

[0028] The average thickness of the first plate material 11 is determined appropriately so that the musical instrument soundboard 1 can obtain the desired loss tangent and anisotropy thereof, but from the viewpoint of strength, the lower limit of the average thickness of the first plate material 11 is preferably 0.3 mm, and more preferably 0.4 mm, while from the viewpoint of weight reduction, the upper limit of the average thickness of the first plate material 11 is preferably 1 mm, and more preferably 0.8 mm.

[0029] <Second Plate Material> The second plate material 12 is formed in a plate shape, and is preferably made of a metal.

[0030] Examples of the metal include aluminum, magnesium, or alloys thereof, titanium alloys, brass, and nickel silver. Of these, aluminum, magnesium, or alloys thereof, and titanium alloys are lightweight, making it easy to ensure the volume of the musical instrument soundboard 1. Brass and nickel silver are also expected to produce good tone colors.

[0031] The average thickness of the second plate material 12 is determined appropriately so that the musical instrument soundboard 1 can obtain the desired loss tangent and anisotropy thereof, but from the viewpoint of strength, the lower limit of the average thickness of the second plate material 12 is preferably 0.03 mm, and more preferably 0.05 mm, while from the viewpoint of weight reduction, the upper limit of the average thickness of the second plate material 12 is preferably 0.20 mm, and more preferably 0.15 mm.

[0032] When the raw material of the second plate material 12 is a metal, the second plate material 12 does not exhibit anisotropy. In other words, the ratio of the loss tangent or elastic modulus in the X direction to the Y direction is 1, making it a plate material with the lowest anisotropy.

[0033] <Third Plate Material> The third plate material 13 is formed in a plate shape, and carbon, glass fiber, or basalt fiber can be used as the raw material thereof.

[0034] When carbon is used as the raw material of the third plate material 13, the third plate material 13 is made of carbon fibers impregnated in epoxy resin, such as unidirectional fiber reinforced plastic.

[0035] When carbon is used as the raw material for the third plate material 13, it is preferable that the fiber direction (L direction) is aligned. By aligning the fiber direction, the loss tangent in the fiber direction is reduced and the anisotropy of the loss tangent is enhanced. In this case, the third plate material 13 is preferably used so that the fiber direction is parallel to the surface of the third plate material 13, and the fiber direction is the X direction.

[0036] The average thickness of the third plate material 13 is determined appropriately so that the musical instrument soundboard 1 can obtain the desired loss tangent and anisotropy thereof, but from the viewpoint of strength, the lower limit of the average thickness of the third plate material 13 is preferably 0.10 mm, and more preferably 0.15 mm, while from the viewpoint of weight reduction, the upper limit of the average thickness of the third plate material 13 is preferably 0.35 mm, and more preferably 0.30 mm.

[0037] <Decorative Laminate> The decorative laminate 14 is formed in a plate shape and is intended to add a decorative element to the musical instrument soundboard 1. For this reason, the decorative laminate 14 is laminated on only one side of the musical instrument soundboard 1. The side of the musical instrument soundboard 1 having this decorative laminate 14 is used as the front surface.

[0038] A known decorative plate used for musical instruments can be used as the decorative plate 14. The average thickness of the decorative plate 14 is not limited, but can be, for example, 0.2 mm or more and 0.5 mm or less.

[0039] <Relationship Between First Plate Material, Second Plate Material, and Third Plate Material> In the musical instrument soundboard 1, the third plate material 13 has stronger anisotropy with respect to the loss tangent than the first plate material 11 and the second plate material 12. There are no particular restrictions on the strength of the anisotropy between the first plate material 11 and the second plate material 12, but it is preferable that the anisotropy of the first plate material 11 be stronger.

[0040] It is preferable that the direction in which the loss tangent is smallest for each of the first plate 11, the second plate 12, and the third plate 13 is the long axis direction of the plate. By orienting the plates in this way, it is easy to control the anisotropy to a desired value. When each plate has a multi-layer structure, it is preferable to set the long axis direction of the plate in the direction in which the loss tangent is smallest for all layers. Note that, in a plate whose direction in which the loss tangent is largest is perpendicular to the direction in which the loss tangent is smallest, it is preferable to set the direction in which the loss tangent is also largest in the width direction of the plate.

[0041] The lower limit of the ratio of the loss tangent in the X direction to the Y direction of the first plate material 11 is preferably 0.5, more preferably 0.6, while the upper limit of the ratio of the loss tangent in the first plate material 11 is preferably 1.0, more preferably 0.9.

[0042] The lower limit of the ratio of the loss tangent in the X direction to the loss tangent in the Y direction of the second plate material 12 is preferably 0.7, and more preferably 0.8. On the other hand, the upper limit of the ratio of the loss tangent of the second plate material 12 can be set to 1, which is the theoretical maximum value.

[0043] The lower limit of the ratio of the loss tangent in the X direction to the Y direction of the third plate material 13 is preferably 0.04, more preferably 0.1. On the other hand, the upper limit of the ratio of the loss tangent in the third plate material 13 is preferably 0.43, more preferably 0.25.

[0044] By setting the ratio of the loss tangents of the first plate material 11, the second plate material 12 and the third plate material 13 within the above range, it is possible to easily obtain the desired anisotropy while facilitating independent control of the loss tangent and its anisotropy.

[0045] Furthermore, in this musical instrument soundboard 1, the X-direction loss tangent of the first plate 11 is greater than both the X-direction loss tangent of the second plate 12 and the X-direction loss tangent of the third plate 13. As mentioned above, the third plate 13 has the greatest anisotropy of the loss tangent, meaning that the order of magnitude of the loss tangent and its anisotropy is different. Therefore, by controlling the thicknesses of the first plate 11, second plate 12, and third plate 13, the loss tangent and its anisotropy of the entire musical instrument soundboard 1 can be independently controlled. Therefore, the loss tangent and its anisotropy of the entire musical instrument soundboard can be set to desired values ​​to achieve the desired tone, making it easy to reproduce an excellent tone. Furthermore, because the musical instrument soundboard 1 can be configured with controlled loss tangent and its anisotropy, it can be manufactured consistently.

[0046] The lower limit of the loss tangent in the X direction of the first plate member 11 is 3 × 10 －３ is preferred, and 10 × 10 －３ On the other hand, the upper limit of the loss tangent in the X direction of the first plate member 11 is 60×10 －３ is preferred, and 50×10 －３ is more preferred.

[0047] The lower limit of the loss tangent in the X direction of the second plate member 12 is 0.2 × 10 －３ is preferable, and 0.3 × 10 －３ On the other hand, the upper limit of the loss tangent in the X direction of the second plate member 12 is 10×10 －３ is preferred, and 4 × 10 －３ is more preferred.

[0048] The lower limit of the loss tangent in the X direction of the third plate member 13 is 0.5 × 10 －３ is preferable, and 0.8 × 10 －３ On the other hand, the upper limit of the loss tangent in the X direction of the third plate member 13 is 4×10 －３ is preferred, and 2.5 × 10 －３ is more preferred.

[0049] By setting the loss tangent in the X direction of the first plate material 11, the second plate material 12, and the third plate material 13 within the above range, it is possible to easily obtain the desired loss tangent while facilitating independent control of the loss tangent and its anisotropy.

[0050] The lower limit of the loss tangent in the Y direction of the first plate member 11 is 3 × 10 －３ is preferred, and 10 × 10 －３ On the other hand, the upper limit of the loss tangent in the Y direction of the first plate member 11 is 60×10 －３ is preferred, and 50×10 －３ is more preferred.

[0051] The lower limit of the loss tangent in the Y direction of the second plate member 12 is 0.2 × 10 －３ is preferable, and 0.3 × 10 －３ On the other hand, the upper limit of the loss tangent in the Y direction of the second plate member 12 is 10×10 －３ is preferred, and 4 × 10 －３ is more preferred.

[0052] The lower limit of the loss tangent in the Y direction of the third plate member 13 is 5 × 10 －３ is preferred, and 7 × 10 －３ On the other hand, the upper limit of the loss tangent in the Y direction of the third plate member 13 is 40×10 －３ is preferred, and 20 × 10 －３ is more preferred.

[0053] By setting the loss tangent in the Y direction of the first plate member 11, the second plate member 12 and the third plate member 13 within the above range, it becomes possible to more easily reproduce an excellent tone quality.

[0054] It is also preferable that the third plate material 13 has a stronger anisotropy in the modulus of elasticity than the second plate material 12. By making the third plate material 13 have a stronger anisotropy in the modulus of elasticity than the second plate material 12, it becomes possible to more easily reproduce an excellent tone color.

[0055] The first plate material 11 and the second plate material 12 may have the same degree of anisotropy with respect to the elastic modulus, or the second plate material 12 may have a stronger anisotropy, but it is preferable that the first plate material 11 has a stronger anisotropy than the second plate material 12. By making the first plate material 11 have a stronger anisotropy with respect to the elastic modulus than the second plate material 12 in this way, it becomes even easier to reproduce an excellent tone color.

[0056] When a natural wood exists as a target for sound quality, it is preferable that the loss tangent of the first board 11 be large and the loss tangents of the second board 12 and the third board 13 be small relative to the natural wood, and that the anisotropy of the loss tangent of the first board 11 and the second board 12 be weak and the anisotropy of the loss tangent of the third board 13 be strong relative to the natural wood. By setting the loss tangent and anisotropy in this manner, the loss tangent and anisotropy of the entire musical instrument soundboard 1 can be easily matched to the loss tangent and anisotropy of the natural wood. Therefore, it is possible to reproduce a sound that is close to the sound quality of the specific natural wood.

[0057] An example of natural wood that has the desired sound quality is rosewood.

[0058] Furthermore, it is preferable that the first board 11 has a stronger anisotropy of elastic modulus than the natural wood, and the second board 12 has a weaker anisotropy than the natural wood. By setting the elastic modulus in this way, the elastic modulus of the entire musical instrument soundboard 1 can be made closer to that of the natural wood. Therefore, it is possible to reproduce a sound that is closer to the quality of the specific natural wood.

[0059] The pair of third plates 13 are preferably configured symmetrically in the thickness direction about a bisecting plane M that bisects the distance between the pair of third plates 13. That is, as shown in Figure 1, the first plate 11 is positioned so that the bisecting plane M is located in the center of the thickness direction, and the pair of second plates 12 are positioned so that they are equidistant from the bisecting plane M. By configuring them symmetrically in the thickness direction in this way, all of the plates can be produced in a single molding operation while preventing warping of the musical instrument soundboard 1.

[0060] <Method for manufacturing musical instrument soundboard> The musical instrument soundboard 1 can be manufactured by preparing a first plate material 11, a pair of second plate materials 12, a pair of third plate materials 13, and a decorative panel 14, forming a first laminate by laminating the pair of second plate materials 12 on both sides of the first plate material 11, forming a second laminate by laminating the pair of third plate materials 13 on both sides of the first laminate, and laminating the decorative panel 14 on one side of the second laminate.

[0061] The pair of second plate materials 12 and the pair of third plate materials 13 can be laminated using pressure bonding by pressing or adhesive bonding. Furthermore, if fiber-reinforced plastic is used for the first plate material 11, the second plate material 12, or both, the plate materials using fiber-reinforced plastic may be laminated as semi-cured fiber-reinforced plastic prepregs, and the first laminate may be heat-cured. In this case, the resin contained in the prepreg acts as an adhesive to bond the fiber-reinforced plastic to adjacent plate materials. Furthermore, when plate materials that do not contain resin are adjacent to each other, it is preferable to sandwich a semi-cured resin sheet between them during lamination. The decorative laminate 14 can be laminated, for example, using an adhesive.

[0062] 2 and 3 mainly comprises a hollow body 22 having a soundboard 21, a bridge 24 attached to the outer surface of the soundboard 21 and supporting multiple strings 23, a saddle 25 attached to the outer surface of the bridge 24, a neck 26 connected to the body 22 and extending from one end of the soundboard 21, and a head 27 attached to one end of the neck 26. One ends of the multiple strings 23 are wound around and secured to multiple pegs 28 attached to the head 27, and the other ends are supported by the bridge 24 via the saddle 25 and secured to multiple pins 29. The soundboard 21 also has a sound hole 30 between the other end of the neck 26 and the bridge 24. The string instrument 2 is configured as an acoustic guitar that produces a predetermined volume of sound by causing the vibrations of the strings 23 to resonate with the body 22.

[0063] The stringed instrument 2 includes a soundboard 21, which is the instrument soundboard 1 shown in Figure 1. Specifically, as shown in Figures 2 and 3, the soundboard 21 of the body 22 is made up of a top panel 21a, side panels 21b, and a back panel 21c, with the instrument soundboard 1 being used for the side panels 21b and back panel 21c. By using the instrument soundboard 1 for the side panels 21b and back panel 21c in this way, an excellent tone can be achieved.

[0064] [Other Embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as falling within the scope of the present invention.

[0065] In the above embodiment, the musical instrument soundboard is described as being composed of a first plate material, a second plate material, a third plate material, and a decorative plate, but the decorative plate is not an essential component and can be omitted.

[0066] Further, other plates may be provided between the first plate and the second plate, between the second plate and the third plate, and on part or all of the outside of the third plate. The material of the other plates may be the same as the material of the other layers in the first plate of the above embodiment.

[0067] When the other plate members are provided, it is preferable that the soundboard for a musical instrument, including the other plate members, be configured symmetrically in the thickness direction about a plane that bisects the distance between the pair of third plate members. In other words, if the other plate members are provided between the second and third plate members, for example, the other plate members will be arranged in pairs facing each other with the pair of second plate members in between.

[0068] In addition, the average thickness of each of the other plate materials is preferably smaller than the average thickness of any of the first plate material, the second plate material, and the third plate material, in order to reduce the effect on the tone color.

[0069] The stringed instrument is not limited to the acoustic guitar mentioned above, but may be, for example, an electric acoustic guitar, a classical guitar, a violin, a cello, a mandolin, or the like.

[0070] Furthermore, the musical instrument soundboard may be used as a diaphragm for keyboard instruments such as pianos, in addition to the stringed instruments mentioned above.

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0072] [No. 1] A soundboard for a musical instrument was prepared, which included a first plate, a pair of second plates arranged opposite each other with the first plate sandwiched therebetween, a pair of third plates arranged opposite each other with the pair of second plates sandwiched therebetween, and a decorative plate on the outside of one of the third plates.

[0073] The first plate has a loss tangent in the X direction that is larger than both the loss tangent in the X direction of the second plate and the loss tangent in the X direction of the third plate. The third plate has stronger anisotropy in loss tangent than the first plate and the second plate.

[0074] Furthermore, the soundboard for musical instruments is configured such that the pair of third plates are symmetrical in the thickness direction about a bisecting plane that bisects the distance between the pair of third plates.

[0075] The musical instrument soundboard was used to make No. 1 guitar.

[0076] [No. 2] A soundboard for musical instruments was prepared, which was made of rosewood and had a decorative panel on one side. Rosewood, a natural wood, is known for its excellent tone quality when used as a soundboard for musical instruments.

[0077] The thickness of the rosewood board was the same as the combined thickness of the first board, the pair of second boards, and the pair of third boards of the No. 1 musical instrument soundboard. The decorative board was also the same as that of the No. 1 musical instrument soundboard.

[0078] This instrument soundboard was used to make guitar No. 2.

[0079] [Evaluation] The saddles of guitars No. 1 and No. 2 were struck, the sound was recorded with a microphone, and the frequency characteristics were analyzed. The results for No. 1 are shown in Figure 4, and the results for No. 2 are shown in Figure 5.

[0080] The graphs in Figures 4 and 5 are very similar, and it is determined that guitar No. 1, which uses the musical instrument soundboard of the present disclosure, has a tone quality equivalent to guitar No. 2, which uses rosewood, which is known to have a good tone quality.

[0081] As described above, the musical instrument soundboard of the present disclosure and the stringed instrument using this musical instrument soundboard can be manufactured stably and have excellent tone quality.

[0082] 1 Musical instrument soundboard 11 First plate material 12 Second plate material 13 Third plate material 14 Decorative plate 2 Stringed instrument 21 Soundboard 21a Top plate 21b Side plate 21c Back plate 22 Body 23 Strings 24 Bridge 25 Saddle 26 Neck 27 Head 28 Tuner 29 Pin 30 Sound hole M Bisecting surface

Claims

1. A soundboard for a musical instrument comprising: a first plate; a pair of second plates arranged opposite each other with the first plate in between; and a pair of third plates arranged opposite each other with the pair of second plates in between, wherein the third plate has stronger anisotropy with respect to loss tangent than the first and second plates, and when the direction parallel to the surface of the third plate and in which the loss tangent of the third plate is smallest is defined as the X-direction, the loss tangent in the X-direction of the first plate is greater than both the loss tangent in the X-direction of the second plate and the loss tangent in the X-direction of the third plate.

2. The loss tangent in the X direction of the first plate is 3×10 －３ Above 60 x 10 －３ The loss tangent in the X direction of the second plate is 0.2×10 or less. －３ Above 10 x 10 －３ The loss tangent in the X direction of the third plate is 0.5×10 or less. －３ Above 4 x 10 －３ 2. A musical instrument soundboard as claimed in claim 1, wherein:

3. When the direction parallel to the surface of the third plate and perpendicular to the X direction is the Y direction, the loss tangent of the first plate in the Y direction is 3×10 －３ Above 60 x 10 －３ The loss tangent in the Y direction of the second plate is 0.2×10 or less. －３ Above 10 x 10 －３ The loss tangent in the Y direction of the third plate is 5×10 or less. －３ Above 40 x 10 －３ 3. A musical instrument soundboard according to claim 1 or 2, wherein:

4. A soundboard for a musical instrument as claimed in claim 1 or 2, wherein the ratio of the loss tangent in the X direction to the Y direction of said first plate material is 0.5 or more and 1 or less, the ratio of the loss tangent in the X direction to the Y direction of said second plate material is 0.7 or more and 1 or less, and the ratio of the loss tangent in the X direction to the Y direction of said third plate material is 0.04 or more and 0.43 or less.

5. A musical instrument soundboard as claimed in claim 1 or 2, wherein the third plate material has a stronger anisotropy in elastic modulus than the second plate material.

6. A soundboard for a musical instrument as claimed in claim 1 or claim 2, wherein the raw material of the first plate material is high-elasticity fiber or wood, the raw material of the second plate material is metal, and the raw material of the third plate material is carbon, glass fiber or basalt fiber.

7. A soundboard for a musical instrument as described in claim 1 or claim 2, wherein the space between the pair of third plates is configured symmetrically in the thickness direction around a bisecting plane that divides the space between the pair of third plates in half.

8. A stringed instrument comprising a musical instrument soundboard according to claim 1 or 2.

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