WO2012082932A2

WO2012082932A2 - Soundboards and methods of manufacturing soundboard materials

Info

Publication number: WO2012082932A2
Application number: PCT/US2011/064961
Authority: WO
Inventors: Jesse Savage
Original assignee: Jesse Savage
Priority date: 2010-12-15
Filing date: 2011-12-14
Publication date: 2012-06-21
Also published as: WO2012082932A3

Abstract

Soundboards that can be used in acoustic and musical instruments are disclosed. Disclosed methods of manufacturing soundboards from a larger block of soundboard material support high volume production methods.

Description

SOUNDBOARDS AND METHODS OF MANUFACTURING SOUNDBOARD

MATERIALS

RELATED APPLICATIONS

This application claims benefit of priority to U.S. Provisional Patent

Application 61/423,580, filed December 15, 2010, which is hereby incorporated by reference in its entirety as if fully set forth herein.

FIELD OF THE DISCLOSURE

This disclosure relates to soundboards, and methods of manufacturing soundboards and soundboard materials.

BACKGROUND OF THE DISCLOSURE

A soundboard is board that can be used to amplify vibration from a source to produce sound. One source of vibration could be the strings of a musical instrument, which may be connected to a soundboard directly, or connected indirectly for example through a device such as a bridge. When the strings of a musical instrument are played, the vibrations of the strings induce vibration of the soundboard, and the vibration of the soundboard in turn produces sound. The soundboard can also form part of a resonant chamber, such as the body of a guitar, violin or piano.

Traditional materials used in making soundboards include various kinds of wood, with boards made from quarter- sawn, old growth spruce often described as providing superior, long lasting acoustic qualities. The use of old growth spruce, however, has several drawbacks. Soundboards made from spruce can vary with respect to sound quality. Spruce and other woods are sensitive to temperature and humidity, and therefore soundboards distort when environmental conditions change. Often, when an instrument is transported between two climates, the instrument does not express the same sound qualities in each climate, making travelling with a musical instrument difficult. The harvesting of old growth spruce has a negative impact on the

environment, and because the demand for spruce outpaces supply, high volume manufacturing methods cannot be accommodated.

Man-made, wood-based compositions, such as plywood and laminated woods, have been used in soundboards. Composite soundboards that include carbon or other fibers are also known to those in the art. In such cases, composite layers of material that are used in the composition are often formed from one or more plies of composite material laid parallel to the outer or inner surface of the soundboard. The resultant soundboards are often strong, lightweight, and dimensionally more stable than their wood counterparts, but the sound produced by soundboards with man-made

components is generally considered inferior in comparison to the sound produced by wooden soundboards.

BRIEF SUMMARY OF THE DISCLOSURE

The disclosure relates to soundboards that combine layers of wood and composite materials in a novel manner, and provides methods of making such soundboards that can support a high volume manufacturing plan. The soundboards of the present disclosure exhibit superior thermal and dimensional stability, and superior sound quality.

In a first aspect, the disclosure includes a soundboard with outer surfaces and outer edges that includes at least one ply of dampening material and at least one ply of composite material. The plies of composite material are disposed such that the outer surfaces of the soundboard comprise the edges of the plies of composite material.

In a second aspect, the disclosure includes soundboard material formed from at least one ply of dampening material and at least one ply of composite material. The soundboard material is machined to create a soundboard in which the outer surfaces of the soundboard comprise the edges of the plies of composite material. The material may include adhesive.

In an additional aspect, the disclosure includes a method of forming

soundboard material by adhering together at least one ply of dampening material and at least one ply of composite material. The resulting source material is then machined to produce a soundboard in which the outer surfaces of the soundboard comprise the edges of the plies of composite material. The material may include adhesive.

In some embodiments, the apparatus and methods of the disclosure are practiced in relation to acoustic musical instruments. In many cases, the soundboard will be used to form part of a musical instrument, or part of a resonant body in a musical instrument. Instruments may include without limitation guitars, violins, violas, cellos, basses, mandolins, ukuleles, banjos and pianos.

In other embodiments, the inventions of the disclosure are practiced in relation to boards that assist in amplifying or projecting speech.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a soundboard of the present disclosure.

Figure 2A is a schematic of a portion of an edge of a disclosed soundboard.

Figure 2B illustrates a portion of an edge of a disclosed soundboard.

Figure 3 illustrates soundboard material that may be used to produce a soundboard.

Figure 4 shows a bracing scheme for a guitar soundboard of the disclosure. Figure 5 illustrates a portion of an end of a brace.

Figure 6 shows a violin body with a soundboard of the disclosure.

Figure 7 illustrates a portion of an edge of a violin soundboard.

Figures 8 A and 8B illustrate sectional views of potential embodiments of a violin.

DETAILED DESCRIPTION OF MODES OF PRACTICING THE DISCLOSURE

Composite soundboards in the art are traditionally formed from layers of material placed parallel to the outer surfaces of the soundboard. Plies of material are stacked together so that the additive thicknesses of the plies form the thickness of the soundboard. Such soundboards have good strength to weight ratio properties, and the strength characteristics of the soundboard can be analyzed and predicted. In typical manufacturing methods, a ply of material is laid on a tool surface, and additional plies of materials are added to achieve the desired thicknesses and contours. The plies of materials may be pre-impregnated with adhesive, or adhesive may be added to fiber plies. The methods of producing such composites can be time intensive and laborious, particularly if the layers must be placed with precision. The edges of the end product boards can be trimmed, and holes or cuts made in a direction through the thickness of the soundboard, but in general the main outer and inner surfaces are not further formed by machining to remove thicknesses. Such machining could result in damage to the layers or plies in the soundboard.

In contrast, the inventions of the disclosure include soundboards that are also formed with plies of composite material, however, the composite plies are not oriented so that the length and width of the ply are flat or parallel to the main surfaces of the soundboard. Instead, the composite plies are rotated such that the edges of the plies are common to the outer surfaces of the soundboard. The thickness of the soundboard is therefore not identical to the total thicknesses of the composite plies stacked together, but instead the thickness is determined by the width of the composite ply. Put another way, the plies have been rotated approximately 90 degrees so that the edges of the plies, rather than the face of the plies, are common to the outer surfaces of the soundboard.

As described herein, the disclosure includes a soundboard comprising a first principal outer surface and a second principal opposing outer surface. The soundboard comprises at least one ply of dampening material and at least one or more plies of composite material. The edges of the soundboard comprise the edges of the plies of composite materials, and optionally the edges of the plies of the dampening material. Sequential plies of the same material form layers of dampening material or layers composite material. Therefore, the soundboards may also have principal outer surfaces that comprise edges of layers of composite material, dampening material, or both. In most embodiments, the soundboard of the disclosure will include more than one ply and layer of dampening material and more than one ply and layer of composite material. The number of plies within each layer, and the number of layers, may be varied within the soundboard. In many cases, the layers of composite and dampening material will be configured in a pattern that is propagated throughout the soundboard. By way of a non-limiting example, in some cases, a single ply of composite material will be alternated with a single ply of dampening material, and the pattern may be repeated in the remaining layers of materials. In other cases, two or more plies of composite material may be disposed between single-ply layers of dampening material, with the feature repeated throughout the soundboard. Of course, any number of dampening material plies can be placed between two layers of composite material layers, and any number of composite material plies can be placed between two layers of dampening material layers. In many cases, the number dampening plies and composite plies are varied in number. The thicknesses of each ply or layer may also be varied. Variations in ply order, and ply thicknesses, may vary throughout the soundboard or only in isolated portions of the soundboard. Such variation may be used to achieve desired physical properties, such as density, dimensional or thermal stability, or sound quality properties. In some embodiments, the soundboard may further comprise additional materials or fillers such as pieces of foam. In yet other embodiments, the plies or layers may be configured to result in air pockets or spaces within the

soundboard. Preferably, the ratio of the number of dampening plies to the number of composite plies is approximately 1: 1; 1: 1.25; 1: 1.5; 1: 1.75; 1:2; 1:3; 1:4; 1:5 or more than 1:5.

In many embodiments, dampening materials of the disclosure may be practiced with wood, wood products, plastic products, ceramics products, resins, epoxies, or combinations thereof. Non-limiting examples of wood include any species of ash, birch, cherry, cedar, koa, mahogany, maple, red oak, walnut, fir, balsa, white oak, or poplar. Non-limiting examples of wood products include plywood, veneers or high pressure laminates. Examples of plastic products include without limitation

polyurethane or foamed polycarbonate. Plies of dampening material may be oriented in any direction relative to the soundboard and to the composite plies in order to achieve desired characteristics or properties. In some instances, the principal outer surfaces of the soundboard may include edges of the plies of dampening material.

In many embodiments, the composite materials of the disclosure may be practiced with sheets, tape, weaves, fabric, wicks, fibers, honeycombs, angles, beads, rods, strips, angles, tubes, stiff eners, frames, rods, blocks, shims or combinations thereof, by way of non-limiting examples. Examples of the materials that can be used include without limitation carbon fiber, reinforced carbon fiber, carbon fiber reinforced polymers, and combinations thereof. In many cases, the composite materials are pre- impregnated with resin. In other cases, resin or epoxy may be applied to the dampening or composite layers before or during the cure process.

In some embodiments, the direction of the composite fibers, or the warp of composite fiber plies, may be oriented such that they are parallel, or substantially parallel, to an axis formed by a string of an acoustic instrument. In other embodiments, the direction of the composite fibers may be oriented at an angle to an axis formed by a string of an acoustic instrument. Of course, the directionality of the composite fibers may be altered to meet strength or load bearing requirements, or to address

manufacturing concerns such as warping, or both.

In most embodiments, the soundboards of the disclosure comprise adhesive as well as composite and dampening layers. In many cases, the adhesive is applied between the plies of composite and dampening materials. In other cases, the adhesive is pre-impregnated into composite or dampening materials. The adhesive used may be cured at room temperature in some cases, and at an elevated temperature in other cases. The adhesive may be cured with or without the application of localized or general pressure, externally supplied or applied through the use of a vacuum. Non-limiting examples of adhesive include wood glues, melamine formaldehyde glues, urea formaldehyde glues, phenol formaldehyde glues and phenolic glues.

In many embodiments, the soundboards of the present disclosure comprise additional exterior layers, finish and/or sealant applied to one or more outer surfaces or one or more edges of the soundboard. In many cases, the first and/or second principal outer surfaces are partially or wholly covered by a protective or decorative outer layer. In some cases, an additional coat or layer of finish, lacquer or sealant is applied to partially or wholly cover the first and/or second principal outer surfaces. Similarly, protective or decorative layers, finishes, lacquer and/or sealants, can be applied to the edges of the soundboard.

An additional embodiment of the disclosure includes soundboards that have bracing applied to the underside, or second principal surface, of the soundboard. In many cases, bracing struts are connected or attached to the back or underside of the soundboard with adhesive or mechanical means. In some instances, the bracing is attached to the soundboard with adhesive during the cure process. The braces may be made from soundboard material as described herein.

As described herein, a soundboard material of the disclosure comprises more than one ply of dampening material and more than one ply of composite material. The number of plies within each layer, and the number of layers, may be varied within the soundboard. In many cases, the layers of composite and dampening material will be configured in a pattern that is propagated throughout the soundboard material. By way of a non-limiting example, in some cases, a single ply of composite material will be alternated with a single ply of dampening material, and the pattern may be repeated in the remainder of the layers of material. In other cases, two or more plies of composite material may be disposed between single-ply layers of dampening material, with the feature repeated throughout the soundboard material. Of course, any number of dampening material plies can be placed between two layers of composite material layers, and any number of composite material plies can be placed between two layers of dampening material layers. In many cases, the number dampening plies and composite plies can be varied in number in any given layer. The thicknesses of each layer may also be varied. Variations in ply order, and ply thicknesses, may vary throughout the soundboard material or only in isolated portions. Such variation may be used to achieve desired physical properties, such as density, dimensional or thermal stability, or sound quality properties. In some embodiments, the soundboard material may further comprise additional materials or fillers such as pieces of foam. In yet other embodiments, the plies or layers may be configured to result in air pockets or spaces within the soundboard material. Preferably, the ratio of the number of dampening plies to the number of composite plies is approximately 1 : 1 ; 1: 1.25; 1 : 1.5; 1: 1.75;1:2; 1:3; 1:4; 1:5 or more than 1:5.

The soundboard material of the present disclosure may be configured such that the material can be machined to produce a soundboard having composite plies are rotated such that the edges of the plies are common to the outer principal surfaces of the soundboard. Put another way, the plies are approximately 90 degrees to the principal surfaces so that the edges of the plies, rather than the face of the plies, are common to the outer surfaces of the soundboard. In some instances, the principal outer surfaces of the soundboard may include edges of the plies of dampening material.

The dampening and composite materials used in the soundboard material may be the same or similar to those that may be used in soundboards of the present disclosure as described herein.

manufacturing concerns such as warping, or both.

In most embodiments, the soundboard material of the disclosure comprises adhesive as well as composite and dampening layers. In many cases, the adhesive is applied between the plies of composite and dampening materials. In other cases, the adhesive is pre-impregnated into composite or dampening materials. The adhesive used may be cured at room temperature in some cases, and at an elevated temperature in other cases. The adhesive may be cured with or without the application of localized or general pressure, externally supplied or applied through the use of a vacuum. Non- limiting examples of adhesive include wood glues, melamine formaldehyde glues, urea formaldehyde glues, phenol formaldehyde glues and phenolic glues.

In many embodiments, the soundboard material may be used to produce a soundboard of the present disclosure. The soundboard material may be processed like natural wood using manual or motor-driven woodworking tools to produce at least one soundboard. Of course, in some instances the soundboard material will be sufficiently large in size to produce more than one soundboard. In some cases, the soundboard material is machined to produce a soundboard with contours or curvature common to one or both principal surfaces, or to edges. In other cases, the soundboard material is machined to produce a flat or substantially flat soundboard.

As described herein, a method of forming a soundboard of the disclosure comprises adhering together more than one ply of dampening material and one or more plies of composite material. At least one ply of the composite material is sandwiched between layers of dampening material. The cured assembly is machined to produce a soundboard having first and second principal outer surfaces comprising the edges of plies or layers of dampening material and composite material. In some cases, the soundboard material is machined to produce a soundboard with contour or curvature common to one or both principal surfaces, or to edges. In other cases, the soundboard material is machined to produce a flat or substantially flat soundboard.

As described herein, a soundboard of the disclosure includes a base having a first principal outer surface and a second principal opposing outer surface. The base may be made wholly or partially from wood, wood products, waste wood, plastic products, ceramics products, resins, epoxies, or combinations thereof. Non-limiting examples of wood include any species of ash, birch, cherry, cedar, koa, mahogany, maple, red oak, walnut, fir, balsa, white oak, or poplar. Non-limiting examples of wood products include plywood, veneers or high pressure laminates. Examples of plastic products include without limitation polyurethane or foamed polycarbonate. The base of the disclosure includes grooves in the base common to the either principal outer surface of the base that run from a first edge portion of the base to a second edge portion of the base. The soundboard includes composite material placed into the grooves. Adhesive, such as resin or epoxy, is also placed into the groove or allowed to wick into the groove during the manufacturing process. In many embodiments, the composite material is carbon fiber tow.

As described herein, a method of forming a soundboard of the disclosure includes cutting or otherwise establishing grooves into a principal outer surface of a base from edge to edge. The groove may take any line or contour within the base. The base may be made wholly or partially from wood, wood products, waste wood, plastic products, ceramics products, resins, epoxies, or combinations thereof. Non-limiting examples of wood include any species of ash, birch, cherry, cedar, koa, mahogany, maple, red oak, walnut, fir, balsa, white oak, or poplar. Non-limiting examples of wood products include plywood, veneers or high pressure laminates. Examples of plastic products include without limitation polyurethane or foamed polycarbonate.

In most embodiments, the method includes placing or disposing composite material into the grooves such that the composite material extends past the end of the grooves. In many cases, covering the assembly with a wicking layer takes place prior to curing the assembly under vacuum, while allowing resin or epoxy to wick into the groove from the composite material that extends out from the groove. In many embodiments, the composite material is carbon fiber tow. Having now generally provided the disclosure, the same will be more readily understood through reference to the following examples which are provided by way of illustration, and are not intended to be limiting of the disclosure, unless specified.

EXAMPLES

Example 1: An acoustic guitar soundboard 100 is shown in Figure 1. Soundboard 100 includes birch wood layers 110 and carbon fiber layers 120.

Soundboard 100 is cured at room temperature. After curing, a protective and/or decorative layer 140 is applied to the upper surface of the soundboard. The edges are subsequently machined to produce edge contours 150.

Figure 2A is a schematic of a portion of an edge of one embodiment of soundboard 100 that includes carbon fiber ply 120 between birch wood layers 110. The fibers 121 of carbon fiber ply 120 are substantially parallel to axis 130, or the axis that would be formed by a string of the guitar. Adhesive is disposed in fibers 121 to adhere fibers 121 to birch wood layers 110.

Figure 2B is a schematic of a portion of an edge of another embodiment of soundboard 100 that includes carbon fiber plies 122 in layers 120 between plywood layers 110. Three carbon fiber plies 122 are shown in the figure. The three plies that form layers 120 are sheets of carbon fiber fabric weave pre-impregnated with epoxy, and the warp of the fabric plies parallels guitar string axis 130. The edges of plywood layer 110 form part of the upper and lower surfaces of the soundboard.

Example 2: Soundboard material 200 is illustrated in Figure 3.

Soundboard material 200 includes layers of birch wood 210 and carbon fiber layers 220. Carbon fiber layers 220 have materials that pre-impregnated with epoxy with the load bearing fibers placed parallel to guitar string axis 130. Soundboard material 200 is cured at room temperature under vacuum pressure. Soundboard material 200 is of sufficient height, width and depth to be machined through conventional means to produce one or more guitar soundboards 100 shown in outline in Figure 3.

Example 3: In Figure 4, braces 310 are shown attached to soundboard 300 having a first principal outer surface 301 and a second principal outer surface 302.

Braces 310 and finger braces 320 are glued onto second principal outer surface 302 with wood glue after soundboard 300 is cured. In other instances, braces 310 and finger braces 320 may be joined to soundboard 300 with epoxy and co-cured with the soundboard. Figure 5 illustrates a portion of an end of brace 310. Brace 310 may be formed from soundboard material 200 having wood layers 210 and composite layers 220. Protective and/or decorative layer 140 is applied to the upper surface of the soundboard 301. Clear protective finish is applied to second principal outer surface 302.

Example 4: In Figures 6, 7, 8A and 8B, the body of violin 400 is illustrated with base 500 made from wood or wood products. Exterior outer surface 501 has been cut from edge to edge to form grooves 510. Figure 7 illustrates carbon fiber tow 520 hand-laid into grooves 510 so that the direction of the tow is guided by the grooves. Epoxy 530 is added to grooves 510 and the assembly is cured together with decorative outer layer 550, which may be designed to look like natural wood grain.

Figures 8 A and 8B illustrates sectional views of potential embodiments of violin body 400 through base 500. In Figure 8A, base 500 is formed from soundboard material with layers of composite and dampening material. In Figure 8B, base 500 is formed from plywood. Both exterior outer surface 501 and interior surface 502 have been cut from edge to edge to form grooves 510 and 540 respectively. Carbon fiber tow 520 and adhesive 530 are in grooves 510 and grooves 540. Decorative outer layer 550 covers exterior outer surface 501 and clear finishe is applied to interior surface 502.

Having now fully described the inventive subject matter, it will be appreciated by those skilled in the art that the same can be performed within a wide range of equivalent parameters, concentrations, and conditions without departing from the spirit and scope of the disclosure and without undue experimentation.

While this disclosure has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains and as may be applied to the essential features hereinbefore set forth.

Claims

WHAT IS CLAIMED IS:

1. An acoustic instrument soundboard having a first principal outer surface and a second principal opposing outer surface, said soundboard comprising more than one ply of dampening material; and

one or more plies of composite material, wherein at least one ply of said composite material is disposed between said plies of dampening material; and

wherein the first and second principal outer surfaces comprise the edges of plies of composite material.

2. The soundboard of claim 1, wherein the first and second principal outer surfaces further comprise the edges of plies of dampening material.

3. The soundboard of claim 1, wherein said dampening material is selected from wood, wood products, plastic products, ceramics products, resins, epoxies, or combinations thereof.

4. The soundboard of claim 3, wherein said dampening material is selected from plywood, veneers or high pressure laminates.

5. The soundboard of claim 4, wherein said wood is ash, birch, cherry, cedar, mahogany, maple, red oak, walnut, fir, balsa, white oak, or poplar.

6. The soundboard of claim 5, wherein said wood is birch.

7. The soundboard of claim 3, wherein said plastic product is polyurethane or foamed polycarbonate.

8. The soundboard of claim 1, wherein said composite material comprises carbon fiber.

9. The soundboard of claim 8, wherein said composite material comprises carbon fiber pre-impregnated with resin.

10. The soundboard of claim 9, wherein said carbon fibers are oriented substantially parallel to the strings of the acoustic instrument.

11. The soundboard of claim 1, further comprising adhesive.

12. The soundboard of claim 11, wherein said adhesive is applied between said plies.

13. The soundboard of claim 9, wherein said adhesive is wood glue.

14. The soundboard of claim 1, wherein the ratio of the number of dampening plies to the number of composite plies is approximately 1: 1.

15. The soundboard of claim 1, wherein said first principal outer surface is partially or wholly covered by a protective outer layer.

16. The soundboard of claim 1, wherein said first principal outer surface is partially or wholly covered by a decorative outer layer.

17. The soundboard of claim 1, further comprising braces within said acoustic instrument disposed on said second principal surface.

18. A composite material comprising

more than one ply of dampening material; and

adhesive,

wherein said composite material is machined for an acoustic instrument soundboard having first and second principal outer surfaces comprising the edges of plies of composite material.

19. The composite material of claim 18, wherein the first and second principal outer surfaces of said soundboard further comprise the edges of plies of dampening material.

20. A method of forming an acoustic instrument soundboard, comprising adhering together more than one ply of dampening material and one or more plies of composite material, wherein at least one ply of said composite material is disposed between said plies of dampening material; and

machining said adhered plies for an acoustic instrument soundboard having first and second principal outer surfaces comprising the edges of plies of dampening material and composite material.

21. The method of claim 20, wherein said first and second principal outer surfaces are substantially flat.

22. The method of claim 20, wherein said first and second principal outer surfaces are contoured.

23. An acoustic instrument soundboard, said soundboard comprising a base having a first principal outer surface and a second principal opposing outer surface, said base formed from wood, wood products or waste wood, wherein said base comprises at least one groove common to said first principal outer surface;

composite material disposed in said grooves; and

resin,

wherein said grooves run from edge to edge in said base.

24. The soundboard of claim 23, wherein said composite material is carbon fiber tow.

25. A method of forming an acoustic instrument soundboard, comprising cutting grooves into a base having a first principal outer surface and a second principal opposing outer surface, said base formed from wood, wood products or waste wood, wherein said grooves are cut into said first principal outer surface;

placing composite material into said grooves; and

curing said soundboard in the presence of resin.

26. The method of claim 25, wherein said composite material is carbon fiber tow.