CA2683587A1 - A structurally balanced, frame supported, mathematically tuned, acoustically amplified instrument - Google Patents

Abstract

In an acoustic guitar, it is known to have strings suspended over and attached to or rested on a piece of wood that is tensioned by those strings, causing the wood to vibrate when the tensioned strings are plucked. That wood becomes the top of and is permanently attached to a wooden chamber that is intended to give volume and direction to the strings' vibrations. That chamber is permanently or non permanently attached to a solid wood neck. The neck is to allow the human hand to temporarily change string length and therefore frequency of string vibrations.
Permanently attached to the neck is a fret board which regulates changes with stops known as frets. There are, as far as is practicably measurable, an infinite number of groups, known as octaves, each comprised of twelve equally tempered divisions, in the harmonic musical scale, and the terminus of the first octave, along with the location of the twelfth fret, is the middle of the string. This is the harmonic centre of the string and where most stringed instruments join the neck to the chamber. Strings must be tensioned to vibrate at the specific frequencies associated with guitars and that tension originates at adjustable tuners located at the outboard end of the neck and terminates either at the end of the chamber or at some point on the top of it. The vibrating element, the amplifying element, the structural element that opposes string tension and the shape and size of the instrument are all integral to each other structurally, cosmetically and acoustically.

In this invention, the neck of the guitar is hollow and runs the length of the instrument. It is structurally in balance, has total control of opposition to string tension and is the primary means of introducing vibrations into the instrument.
The ends of the neck are identical except for an inverse arrangement of string purchase, equalizing string lengths and leverages and focusing the forces opposing string tension at the twelfth fret. On steel string guitars, steel reinforcement runs the length of the neck and is tuned, in the hollow chamber, to string length, string pull and harmonic center. The neck is not integral to the shape of the guitar or the amplifier and is permanently attached to a frame, a back and a top by being built integral to them. The top, other than where it contacts the frame and the neck and the small portion between the inboard end of the neck and the inboard end of the frame, is largely decorative and can be removed in large or small quantities to allow for acoustical balance between the vibrations being sent into the amplifier and those being sent back out and for decoration. The frame alone is built structurally integral to the shape of the guitar. Non-permanently attached to the frame and opening at the twelfth fret, is an acoustically diffusive amplifier, mathematically tuned to the harmonic centre of the instrument and fractal in three planes.

It is also known that an acoustic guitar is made of wood and it is accepted that solid wood is superior to plywood in the construction of acoustic guitars. In instances where some product other than wood is used, an acoustic guitar is built in the same manner as one made with wood, in that the resonating chamber consists of sides, a back and a top, in a clearly recognizable and accepted configuration. The top and back are usually arched to some degree. The neck of the guitar is made separately and attached to the body with glue or screws.

In this invention, the guitar is made of one eighth inch no void Birch plywood, similar to the type used to construct some aircraft. It is possible that no product in the world has better strength to flexibility to weight to price ratios than high quality no void Birch plywood. It is arranged in layers, staggered as to grain orientation and, through alterations made to each layer, forms three elements:
The neck, integral to the structural control of string tension and acoustical control of string vibrations; the frame, integral to the structural and cosmetic shape of the guitar and permanently attached to the neck and, together with the top and back, comprise the frame/neck assembly. The top and back are structurally and cosmetically integral to the frame, structurally integral to the neck and acoustically integral to both the generation and the amplification of vibrations; and the amplifier, which is built separately from, then non-permanently attached to the frame and is acoustically integral with the neck, the top and the back on its inner surface and cosmetically integral to the frame on its outer surface.

It is also known that a hollow body guitar can be tensioned by either nylon or steel strings and that a hollow body guitar with steel strings cannot be built without reinforcing the wood as the tension required to make steel strings vibrate at usable frequencies exceeds the limits of a wooden neck and top to oppose that tension and that those reinforcements were not built integral to the guitar but were added on to an existing design.

In this invention, the neck runs the length of the instrument, is hollow, is structurally in balance, is the main element transferring vibrations into the amplifier and in total control of string tension. On steel string guitars, a steel rod runs the length of the guitar inside the hollow chamber, which is on the same plane as string attachment and, through the use of shims, divides opposition to string tension between each end of the neck and the twelfth fret.

It is also known that a hollow body guitar is assembled permanently and that assembly, disassembly and repairs require high skill levels and specialized equipment.

In this invention, the fret board, which is the wear element, and the amplifier, are attached non-permanently. Assembly, disassembly, external and internal repairs or modifications do not require high skill levels or specialized equipment.

Description

Specifications This invention relates to a tuned, acoustically diffusive chamber for amplifying and directing specific vibrations from an acoustic instrument; the control of string tension necessary for introducing specific vibrations into that chamber in stringed acoustic instruments; and the method of designing and constructing acoustic instruments in general.

It is common in acoustic instruments, such as drums, violins and guitars, to use an amplifying chamber to give volume and direction to vibrations produced or controlled by one element of the chamber as a result of some force, independent of the chamber, being exerted upon that element. That force could be in the way of a strike, a series of strikes or the oscillations of some element, under tension or not, so close together and so consistently repetitive that the struck element vibrates at or near a specific, measurable frequency, alone or in combination with other specific frequencies and whatever harmonics they may produce and which the vibrating element is harmonious to. It is also common in stringed acoustic instruments, such as violins and guitars, to incorporate that amplifying chamber, along with a neck, into the load bearing structure opposing string tension as well as the shape and size of the instrument. The neck's function is to allow the human hand to temporarily change the length of the string and therefore the frequency of string vibration and is required to be thin enough for the human hand to encompass. Designs of this type, however, are inefficient because the resonating chamber is not tuned to the specific frequencies the strings are generating; because the top, being structurally involved in opposing string tension, must cover most of the very chamber it is trying to excite; and because the rear of the amplifying chamber is reflective, not diffusive, to audible frequencies.
This combination distorts the frequencies generated by the strings, limiting both the lower and upper dynamic range of the instrument. These limits have come to be known as "tone". Moreover, the practice of building stringed instruments with an amplifying chamber integral with the structure that opposes string tension as well as the shape of the instrument has led to acoustic stringed instruments requiring a high level of skill and specialized tools to design, construct, assemble, disassemble and repair and dependent upon specific "tone woods" to compensate for their lack of efficiency. Steel stringed instruments are further afflicted by this practice as the force necessary to oppose string tension exceeds the limits of wood at the weakest points of the instrument, the neck and the top, requiring reinforcements that further reduce efficiency, both by what they add and what they fail to add.

I have found that these disadvantages may be overcome by identifying the elements necessary to produce an instrument that looks like and functions as an acoustic guitar: body shape; control of string tension; the formation of an amplifying chamber; and the introduction of string vibrations into that chamber, then dividing those necessary elements between various improved components.
This is further facilitated by a change in instrument design and construction, whereby the instrument is built of thin layers of material, such as high quality no void Birch plywood, where each layer is altered somewhat from each other layer then, permanently or non-permanently, attached and made integral or not integral, physically and/or theoretically, to any other layer, forming elements that become acoustically and/or structurally and/or cosmetically integral or not integral to other elements.

In drawings which illustrate the embodiment of the invention, figure 1 illustrates the neck in side view, figure 2 the neck in top view and figure 3 the neck in end view.

The neck is made up of six layers of 1/8" no void Birch plywood, oriented to give the neck maximum flexibility over the length of the neck. It is physically and theoretically divided at the twelfth fret and is physically and theoretically identical at each end, in relation to length, width, depth and string purchase, except for the inverse arrangement of string purchase shown in figure 2, which allows the overall length of all strings to be identical, and the addition of adjustable tensioners at one end. String purchase is equidistant from the twelfth fret at each end of the neck, is in the middle of the neck at each end, relative to width and depth of the neck and is on the same plane as a '/4 inch square hollow chamber, centred in the neck relative to width and depth and running the length of the neck. The neck could be strung with any string but, since the force required to bring steel strings to the tension necessary to generate the frequencies compatible with steel stringed guitars exceeds the ability of wood, in a structure physically thin enough to function as a guitar neck, to resist that force, a steel rod is added inside the hollow chamber on steel stringed instruments and runs the length of the neck. The steel rod gains its longitudinal purchase and is tensioned at either end of the neck, as shown in figures 1, 2 and 3 and the hollow chamber is internally shimmed, as shown in figures 1, 2 and 3, on the bottom at either end of the neck, extending from the physical end of the neck to the physical end of the string and on the top at the twelfth fret, dividing the rod and the chamber mechanically in relation to neck length and acoustically in relation to string length and giving the rod, under tension, a mechanical advantage over opposition to string tension, in direct but opposite proportion to the length and position of the string(s) being tensioned.
The neck is structurally integral to opposing string tension and acoustically integral to generating string vibration. The neck can be built in an infinite number of variations of length, width, depth and materials and with any or none of its total length outside the perimeter of the frame to accommodate the mounting of an infinite number of known or unknown elements that vibrate at specific frequencies and this invention inherently includes all of those variations.
All six layers of the neck are constructed with and permanently and/or non permanently attached to a frame. Figure 4 illustrates, in top view, the frame, including attachment points for the neck , an inner perimeter compatible with the size and shape of an acoustical amplifier and an outer perimeter compatible with the size and shape of a guitar. The neck attachment point at the twelfth fret is through all six layers of the frame/neck assembly and at the inboard end of the frame is only through the top layer of the frame/neck assembly. The frame is structurally and cosmetically integral to body shape and, through the top and bottom, is acoustically integral with generating and amplifying vibrations.
The frame can be built in an infinite number of variations of size, shape and materials and this invention includes all of those variations.

The top and bottom layers of the neck/frame assembly begin construction with the other layers, then are separated, processed differently, then permanently attached to the neck/frame assembly. Figure 5 illustrates the bottom, in top view. The bottom is modified to eliminate the neck from the inner perimeter of the frame, making the bottom layer of the frame assembly the top layer of the acoustical amplifier and to eliminate some or all of the neck from the outer perimeter of the frame except for the area involved in string purchase and tensioning. This allows, in the string purchase area, the depth required by tensioning machines that are commercially available and commonly associated with guitars, while maintaining, in the outer perimeter and in the neck, depths commonly associated with guitars. The bottom is cosmetically integral to body shape and acoustically integral to amplification of vibrations.

Figure 6 illustrates the top, in top view, in one possible configuration. The top is modified by removing some or all of the material from the areas not in contact with the frame or the neck except the area between the inboard end of the neck and the inboard end of the frame and by adding a fret board and possibly electric pickups. The top vibrates with the neck and contributes to the quality and intensity of the vibrations being directed toward the amplifier but also gets in the way of the return of those vibrations. The top is also a resting place for the hand that is plucking the strings. There are an infinite number of possible ways to add fret boards or pickups or to remove material from the top, in an infinite number of materials and design configurations, either in conjunction with other forms of cosmetics, such as paint schemes, or not. Each one of these infinitely possible ways would create its own balance between the size and shape, color and texture of the material being removed versus the size and shape, color and texture of the material being left and/or added and each would have its own effect upon the nature of the appearance, feel, pitch and tone of the instrument being subjectively perceived by an observer and/or listener and/or player and this invention inherently includes all of those possible variations.

Non-permanently attached to the bottom layer of the frame is the acoustical amplifier, shown in top view in figure 7, in side view in figure 8 and end view in figure 9. The amplifier is diffusive, not reflective, by virtue of being built out of two or more pieces of material, in this case 1/8 no void Birch plywood, with alternate layers of the amplifier being pieces cut out, in alternating sequence, from two or more pieces of material that have been mathematically shaped, then divided fractally in direct relation to the harmonic length of the strings being tensioned.
This results in right angled steps that are divided, in three planes, in direct relation to the base twelve number system which is the basis of the frequencies being introduced into the amplifier. When observed in cross section, these form a combined angle that inherently becomes relative to those frequencies. This construction makes the amplifier fractal in three planes, a characteristic common in highly diffusive acoustical elements. Each successive right angled layer of the amplifier is a smaller, or larger, version of the whole amplifier, in length and width, and a correspondingly nearer or closer version, in depth. The creation of diffusive elements is not purely science. They are not created by the application of science to the angle of reflectors, as in parabolic reflectors, but the application of number theory to the arrangement of right angled steps. Diffusive elements become diffusive simply because they do or because the universe intended them to be. While the efficiency of a diffusive element can be measured, there is no scientific explanation why number theory can and will accomplish diffusion, relinquishing the creation of diffusive elements, at least in part, to the realm of the mystical. The amplifier is acoustically integral to amplification on its inner surface and cosmetically integral to body shape on its outer surface. The diffusive element shown in figures 7, 8 and 9 is built from either two or four pieces of 1/8 inch no void Birch plywood but could be built of any number of pieces greater than two and of any thickness available in no void Birch plywood or of any other compatible material, either cut out separately and assembled, as in this invention, or machined or molded as a whole or manufactured in any other way available now or in the future with or without alterations to the arrangement of the right angled steps, in relation to the application of other aspects of number theory and this invention inherently includes all of those possible variations.

The invention, as described and illustrated, can be modified in scale, shape and number and type of vibrating elements in such a way that it could also be built integral to any element that generates specific frequencies, including any known or unknown stringed or non stringed instruments and this invention inherently includes all of those possible variations.

Claims (5)

1. A manually controlled instrument, of a certain size and physical configuration, such as a guitar, for the generation and acoustic amplification of specific frequencies, comprised of the following elements: a vibrating element; a control element; an acoustic amplifying element; and a frame element.

2. An instrument as defined in claim 1, in which the neck, being the control element, physically supports a vibrating element, such as a steel string under tension, allows for manual control of that element and opposes any force necessary for tensioning that element if tensioning is inherent to that element.

3. An instrument as defined in claim 1 or claim 2, in which the amplifier, being the acoustic amplifying element, is designed in direct relationship to the specific frequencies produced by the vibrating element and located at precise points in relation to that element. The amplifier is developed according to number theory and is fractal in nature. It is diffusive, not reflective.

4. An instrument as defined in claim 1 or claim 2 or claim 3, in which the frame, being the frame element, maintains the neck and amplifier in correct alignment with the vibrating element and offers a certain interior opening to the amplifier and exterior shape to the instrument.

5. An instrument as defined in claim 1 or claim 2 or claim 3 or claim 4, in which the elements that comprise the instrument are constructed and permanently or non permanently attached to each other in a manner that increases efficiency of performance as well as ease of design, construction, assembly, disassembly, modification and repair.

B. In the case of a process:

1. A process for building a manually controlled instrument, such as a guitar, of a certain size and physical configuration, for the generation and acoustic amplification of specific frequencies, comprised of the following elements: a vibrating element; a control element; an acoustical amplifying element; and a frame element.

2. A process for building an apparatus, as described in claim 1, which comprises layering pieces of material, such as 1/8 inch no void Birch plywood, in such a way that each of the layers is altered in some way to make it integral or not integral, physically and/or theoretically, to any other layer and structurally and/or cosmetically and/or acoustically integral or not integral to each of the elements comprising the apparatus.