Note: Descriptions are shown in the official language in which they were submitted.
CA 02683587 2009-10-29
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.
CA 02683587 2009-10-29
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
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CA 02683587 2009-10-29
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
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CA 02683587 2009-10-29
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.
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