The present disclosure generally relates to soundboards and backboards of an acoustic guitar or other acoustic stringed instrument and process for creating the same. Generally, a guitar body comprises of components such as a soundboard (or front plate), a backboard (or back plate), rims, and braces. The soundboard is a frontal piece of the guitar containing the sound hole, and is typically constructed with a thin piece of wood approximately 100 mil (i.e., 2.54 millimeters) thick and reinforced with a set of braces on the immediate backside of the soundboard with other additional components. The backboard is the back piece of the guitar and is generally similar to the soundboard in construction, except that the backboard lacks a sound hole. Between the soundboard and the backboard, there is a rim with a width that separates the frontal soundboard and the opposing backboard to define an enclosure forming the interior or harmonic chamber of the guitar.
Braces are typically placed or attached to the surface of the backside of the soundboard and occupy the space or chamber between the soundboard and the backboard. The placement and design of the braces located on the backside of the soundboard are crucial, as the braces play an important role in the acoustic qualities of the sound produced by the guitar, and also have an impact on the structural integrity of the guitar, serving as structural supports between the soundboard and backboard. The braces also contribute to the mass of the top.
What is desired, therefore, are soundboards and backboards that effectively reduce the overall mass of the top and back of the guitar, while still remaining functional and retaining structural integrity for the braces to be attached to the boards, as well as a board design that allows for the mass and stiffness of the soundboard and backboard to be changed or adjusted to the user's liking or acoustic preference. Further, a brace assembly design is also desired, where the braces may achieve an optimal mass to stiffness ratio, i.e., the braces must be lightweight while also being stiff to withstand the string tension.
For a better understanding of the disclosure, and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying drawings, which:
Referring to
Soundboard 20 includes a plurality of brace channels 36 on bottom surface 26. The brace channels are below the bottom surface so the thickness of soundboard 20 in those channels is less than thickness 32 of the portions of the soundboard without the brace channels (e.g., less than 0.1 inches). In other words, bottom surface 26 defines a first plane and bottom 38 of brace channels 30 are in a second plane generally parallel to and below the first plane. Brace channels 36 are sized and shaped to receive a plurality of structural braces 40. The depth of the brace channels may be the same or different from each other and generally is about 0.020 inches to 0.040 inches. Although brace channels 36 are shown to be rectangular-shaped or have a cross-section that is rectangular-shaped, other examples of soundboard 20 may alternatively, or additionally include brace channels that are shaped differently, such as square, trapezoidal, triangular, semi-circular, etc.
Braces 40 are received in brace channels 36 and are attached to those brace channels and bottom surface 26, such as via one or more adhesives. The braces may be any suitable shape(s) and/or size(s) to reinforce the soundboard, such as to withstand the tension of the strings. Additionally, braces 40 may be any suitable shape(s) and/or size(s) to influence the sound of the soundboard, which may be referred to as “tone braces.” Braces 40 include center braces 42 and side braces 44. In the examples shown in
In the example shown in
Braces 40 includes a base longitudinal layer 54 and a channel longitudinal layer 56 formed with the base longitudinal layer. The base and channel longitudinal layers may be made of any suitable materials, such as one or more lightweight wood materials. Base longitudinal layer 54 has a length 58 and a width 60. Channel longitudinal layer 56 is received in brace channels 36 and has a length 62 and a width 64. For one or more of braces 40, length 62 of channel longitudinal layer 56 is substantially the same (or the same) as length 58 of base longitudinal layer 54, while width 64 of channel longitudinal layer 56 along at least a substantial portion (or all) of length 62 is the same or smaller than width 60 of base longitudinal layer 54 along the corresponding portion of length 58. In the example shown in
Braces 40 may include any suitable cross-section shape(s). In the example shown in
In the example shown in
Soundboard 20 additionally includes a plurality of pockets or cavities 68 separate from the brace channels. The cavities have any suitable shape(s), size(s), and/or pattern(s) that control the acoustic response of the stringed instrument having soundboard 20, such as by providing a desired effect on the amplitude and/or mode shape of the vibrating surface. Additionally, the cavities may reduce the mass and/or stiffness of the soundboard or backboard.
Each cavity 68 is made of one or more side walls 70 and a bottom or bottom wall 71. In the example shown in
The cavities may be distributed on any suitable portion(s) of bottom surface 26 of base 22. In the example shown in
Referring to
Referring to
Referring to
After the edges of the board are straightened, a strip of wood glue (e.g., Titebond wood glue) may be liberally spread on the edges of the board. One side may be pressed into the other side of the board while the board lies flat on the surface of a workbench. The two sides of the board may be pressed together and fixed in place until the glue has dried. Pieces of stretch tape may be used over the seam to hold pieces together, and the pieces are not moved for two hours or until the glue dries. The board may then be processed again to ensure uniform thickness, such as run through a drum sander once again to remove the strip of glue and to ensure the piece is the same thickness throughout.
At 1004, a plurality of brace channels is carved or routed on the bottom surface of the board. The thickness of the board is measured and the measurements are input into a software program such that toolpaths are calculated based on thickness of the board. Those toolpaths are loaded into a CNC router and a suitable router bit is inserted (e.g., 0.125 inch end mill router bit). A spoiler board of a slightly larger size than the board may be used. Strips of double stick tape may be used to attach the board to be routed to the spoiler board and the spoiler board may be clamped on the CNC router bed. The Z-axis of the spindle may be set to zero on top of the board and the X- and Y-axes may be set to zero in the center of the board. The toolpath is run to carve or route the brace channels. When the toolpath is finished, the spoiler and board may be removed from the CNC router bed and subsequently cleaned. The routed board may be pried up using a paint scraper, further shaped, certain portions cut out, and the board cleaned up.
At 1006, braces are attached, such as fastened or glued, to the brace channels of the base. The braces correspond to the brace channels such that at least a portion of the braces are received in the brace channels. When the braces have a T-shaped cross-section, the braces are positioned such that the T-leg portion is received in the brace channels. In some examples, method 1000 may include steps to prepare the braces prior to attachment to the brace channels. For example, at 1010, a composite sheet with a lightweight wood layer and a carbon fiber layer is provided. The composite sheet may be made from a lightweight wood layer, embedding a carbon fiber layer (or other suitable fabric layer) with epoxy or other suitable adhesive, and attaching the carbon fiber layer to the lightweight wood layer.
In some embodiments, a piece of wax paper is lay underneath the carbon fiber, where AB epoxy is mixed together and generously applied to the wood. The brace board is placed on top of the carbon fiber evenly for pressing. A wood board of the same size may be placed on top of the brace board and the carbon fiber fabric, and the two are then pressed into place using multiple three pound weights. This step may take up to 12 to 24 hours of drying and pressing to ensure the brace board, the carbon fiber fabric, and the epoxy are all securely assembled and compressed together. Additionally, at 1012, the braces may be cut from the composite sheet, such as via a CNC router. The shape of the braces may be designed to achieve an optimal mass to stiffness ratio. The width of the braces, such as the layer not received in the brace channels and/or the layer outside the brace channels, may be changed to provide different levels of stiffness.
In some examples, method 1000 may include carving or routing cavities separate from the brace channels to control acoustic response of the soundboard or backboard at 1008, such as via a CNC router. For example, one or more (or all) of the cavities may be hexagonal or elongate. The cavities may be carved or routed to any suitable pattern(s), such as a honeycomb pattern. Although
This section describes additional aspects and features of the soundboards and backboards and the process of manufacturing the same, presented without limitation as a series of paragraphs, some or all of which may be alphanumerically designated for clarity and efficiency. Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing, without limitation, examples of some of the suitable combinations.
A. A soundboard assembly, comprising:
A1. The assembly of A wherein the pockets are a hexagon, and the matrix is a honeycomb shape.
A2. The assembly of A1 wherein each individual brace has a top surface, the top surface has a layer of epoxy immediately thereon, and a layer of carbon fiber cloth immediately thereon the epoxy.
A3. The assembly of A2 wherein the Y-shaped center braces are placed around the center of the back surface of the soundboard, and the two pairs of curved braces include a pair of longer curved braces and a pair of shorter curved braces, and the longer curved braces are placed in an outward location relative to the Y-shaped braces with the pair of shorter curved braces placed outward relative to the longer curved braces on the soundboard.
B. A soundboard assembly, comprising:
C. A soundboard assembly, comprising:
C1. The assembly of C, wherein each individual brace has a top surface, and the top surface has a layer of epoxy on top, and a layer of carbon fiber cloth on top the layer of epoxy.
D. A soundboard or backboard of an acoustic stringed instrument, comprising:
D1. The soundboard or backboard of D, wherein the base further includes a plurality of cavities separate from the plurality of channels.
D2. The soundboard or backboard of D1, wherein one or more cavities of the plurality of cavities are hexagonal.
D3. The soundboard or backboard of D2, wherein each cavity of the plurality of cavities is hexagonal.
D4. The soundboard or backboard of D3, wherein the plurality of cavities is arranged in a honeycomb pattern.
D5. The soundboard or backboard of any of D1 to D4, wherein each cavity of the plurality of cavities is elongate.
D6. The soundboard or backboard of any of D1 to D5, where the base defines a longitudinal axis and wherein the plurality of cavities is symmetrical about the longitudinal axis.
D7. The soundboard or backboard of any of D to D6, wherein one or more of the plurality of braces include a first longitudinal layer and a second longitudinal layer formed with the first longitudinal layer, the first longitudinal layer having a first length and a first width and the second longitudinal layer having a second length and a second width, the first and second length being substantially the same, and the second width along at least a substantial portion of the second length being smaller than the first width along the corresponding portion of the first length.
D8. The soundboard or backboard of D7, wherein the one or more of the plurality of braces includes a third longitudinal layer attached to the first longitudinal layer, the first and second longitudinal layers being made of one or more wood materials, and the third longitudinal layer being made of carbon fiber cloth embedded in epoxy.
D9. The soundboard or backboard of D7 or D8, wherein the one or more of the plurality of braces has a T-shaped cross section having a T-top portion and a T-leg portion that is perpendicular to the T-top portion, the T-top portion being formed by the first longitudinal layer, and the T-leg portion being formed by the second longitudinal layer.
D10. The soundboard or backboard of any of D to D9, wherein the plurality of braces includes a wood layer and a layer having carbon fiber cloth embedded in epoxy attached to the wood layer.
D11. The soundboard or backboard of any of D to D10, where the base has a base length, and wherein the plurality of braces includes a pair of center braces each having a length that is along a substantial portion of the base length.
D12. The soundboard or backboard of D11, wherein the pair of center braces forms a hole that is co-axial with the soundhole and that has a diameter substantially the same as diameter of the soundhole.
D13. The soundboard or backboard of D12, wherein the pair of center braces are substantially mirror images of each other.
D14. The soundboard or backboard of D12 or D13, wherein the plurality of braces includes first, second, third, and fourth side braces, the first, second, third, and fourth side braces being spaced from each other.
D15. The soundboard or backboard of D14, wherein the pair of center braces are disposed between the first and second side braces and the third and fourth side braces.
D16. The soundboard or backboard of D14 or D15, wherein the first and fourth side braces are mirror images of each other, and the second and third side braces are mirror images of each other.
D17. A soundboard of an acoustic stringed instrument, comprising:
D18. An acoustic stringed instrument comprising at least one of the soundboard or backboard of any of D to D17.
E. A method of manufacturing a soundboard or backboard for an acoustic stringed instrument, comprising:
E1. The method of E, further comprising carving a plurality of cavities separate from the plurality of channels to control acoustic response of the guitar soundboard.
E2. The method of claim E1, wherein carving a plurality of cavities separate from the plurality of channels to control acoustic response of the guitar soundboard includes carving the plurality of cavities such that one or more cavities of the plurality of cavities are hexagonal.
E3. The method of claim E2, wherein carving the plurality of cavities such that one or more cavities of the plurality of cavities are hexagonal includes carving the plurality of cavities such that each cavity of the plurality of cavities are hexagonal.
E4. The method of claim E3, wherein carving the plurality of cavities such that each cavity of the plurality of cavities are hexagonal includes carving the plurality of cavities such that the plurality of cavities is in a honeycomb pattern.
E5. The method of any of E1 to E4, further comprising:
E6. The method of claim E5, wherein providing a composite sheet having a lightweight wood layer and a carbon fiber layer includes:
It will be appreciated that the invention is not restricted to the particular embodiment that has been described, and that variations may be made therein without departing from the scope of the invention as defined in the appending claims, as interpreted in accordance with principles of prevailing law, including the doctrine of equivalents or any other principle that enlarges the enforceable scope of a claim beyond its literal scope. Unless the context indicates otherwise, a reference in a claim to the number of instances of an element, be it a reference to one instance or more than one instance, requires at least the stated number of instances of the element but is not intended to exclude from the scope of the claim a structure or method having more instances of that element than stated. The word “comprise” or a derivative thereof, when used in a claim, is used in a nonexclusive sense that is not intended to exclude the presence of other elements or steps in a claimed structure or method.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/088,628 entitled “Brace Assembly and Relief Pockets for Soundboard and Backplate of Acoustic Stringed Instrument,” which was filed on Oct. 7, 2020. The complete disclosure of the above application is hereby incorporated by reference for all purposes.
Number | Name | Date | Kind |
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20130042739 | McPherson | Feb 2013 | A1 |
20170350157 | Knudsen | Dec 2017 | A1 |
Number | Date | Country | |
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20220108671 A1 | Apr 2022 | US |
Number | Date | Country | |
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63088628 | Oct 2020 | US |