Movable tone amplifier for banjos
20180247617 ยท 2018-08-30
Inventors
Cpc classification
International classification
Abstract
A non-electronic device which extracts energy otherwise lost in a banjo's body and converts it into audible sound that not only adds volume to the sound coming from the head, but also makes the sound waves' high frequency components more pronounced. Readily movable from one attachment site to the next along the inside surface of the banjo's cylindrical rim, the device includes a two-dimensional, made-from-cardstock body and, affixed thereto along one end, an elongated strip of acrylic adhesive tape. Suspended from it within the banjo pot, the body routes sound surface waves coming from the rim to various surface wave-amplifying elements including an asymmetrical array of branches and tiny offshoots extending from them, as well as a pair of staples fastened to one branch and a five-sided, irregular timbre polygon hingedly connected to another branch so as to form, with it, a tiny loudspeaker.
Claims
1. A sound enhancing device adapted for use with banjos having a head and a support member therefor which, in assembled relation with each other, define a generally cylindrically shaped sound chamber, wherein the support member includes a cylindrical rim with an inside surface that is substantially as wide as the sound chamber is deep, which comprises: (a) a one piece body cut from cardstock, the body defining a main stem and first and second branches, each of which forks away from the other at the branches' juncture with the main stem in such a way as to form an open-ended passageway; wherein the one piece body further defines four partly circular, recessed edges and three tiny offshoots of said branches which are arrayed, along a substantial portion of the open-ended passageway's periphery, in such a way that the partly circular, recessed edges in each contiguous pair thereof are separated from each other by one of the tiny offshoots, with each of the offshoots, as it projects away from such a contiguous pair's recessed edges and into the passageway, being oriented perpendicularly with respect to at least one of the other offshoots; and (b) means, including an elongated strip of adhesive tape, parts of which are variously affixed to the main stem and, during the device's operation, to the banjo's cylindrical rim, for suspending the one piece body from portions of the rim's inside surface which are disposed generally uppermost when the banjo is being held in its playing position.
2. The device according to claim 1, wherein the first and second branches are further characterized as defining first and second angular terminal ends, respectively, with the latter terminal end having, as one of its lateral sides, a straight edge that both runs generally parallel to the main stem's through centerline and faces one of the partly circular, recessed edges lining the passageway on the first branch's side at the passageway's mouth; and wherein the first angular terminal end's lateral side in closest proximity to said mouth veers away therefrom, so that the first angular terminal end is kept free of any overlap between its periphery and that of the open-ended passageway.
3. The device according to claim 2, which further comprises a pair of staples, each of which is fastened to the second angular terminal end and held in firm contact therewith, wherein the staples so fastened are aligned in parallel with each other and only narrowly spaced apart, with each staple extending crosswise of the second angular terminal end's through centerline and nearly spanning said end's. transverse width.
4. The device according to claim 1, which further comprises a timbre polygon having at least one long, straight edge and means, including an adhesive tape segment affixed to the polygon along said straight edge, with about one-half of the tape segment cantilevered over it and extending generally parallel thereto, for hingedly connecting the timbre polygon to the first branch proximate with its terminal end, wherein the respective edges of the timbre polygon and of the first branch's terminal end are further characterized as being so shaped and sized that said straight edge can be oriented perpendicularly with respect to two of the first branch's edges while it simultaneously spans the distance between them, with the straight edge being so oriented at the same time at least three other edges on the polygon are aligned with a like number of edges bounding the first branch at its terminal end, so that the timbre polygon and the first branch's terminal end, in assembled relation, form a pair of facing surfaces which match each other in shape and size with their respective edges distal from said straightedge's interface with the first branch being spaced apart, thus creating a diverging air space between the facing surfaces.
5. The device according to claim 4, wherein the timbre polygon is further characterized as being an irregular, five-sided polygon.
6. The device according to claim 4, wherein the timbre polygon's long, straight edge over which about one-half of the tape segment is cantilevered is located in such close proximity to one of the partly circular, recessed edges so arrayed along the open-ended passageway's periphery that the tape segment's cantilevered one-half abuts the recessed edge at points thereon disposed approximately midway between said two edges of the first branch that are oriented perpendicularly with respect to the polygon's long, straight edge.
7. A sound enhancing device adapted for use with banjos having a head and a support member therefor which, in assembled relation with each other, define a generally cylindrically shaped sound chamber, wherein the support member includes a cylindrical rim with an inside surface that is substantially as wide as the sound chamber is deep, which comprises: (a) a one piece body cut from a thick piece of paper, the body defining a main stem and first and second branches with variegated first and second angular terminal ends, respectively, wherein each of the branches forks away from the other at the branches' juncture with the main stem so as to form an asymmetricalarray with an open-ended passageway, the mouth of which is bounded on one side by one of the second angular terminal end's lateral side edges at the same time the first angular terminal end's lateral side edge in closest proximity to said mouth veers away from it, so that the first angular terminal end is kept free of any overlap between its periphery and that of the open-ended passageway; and (b) means, including an elongated strip of adhesive tape, parts of which are variously affixed to the main stem and, during the device's operation, to the banjo's cylindrical rim, for suspending the one piece body from portions of the rim's inside surface which are disposed generally uppermost when the banjo is being held in its playing position.
8. The device according to claim 7, which further comprises a timbre polygon having at least one long, straight edge and means, including an adhesive tape segment affixed to the polygon along said straight edge, with about one-half of the tape segment cantilevered over it and extending generally parallel thereto, for hingedly connecting the timbre polygon to the first branch proximate with its angular terminal end, wherein the respective edges of the timbre polygon and of the first angular terminal end are further characterized as being so shaped and sized that said straight edge can be oriented perpendicularly with respect to two of the first branch's edges while it simultaneously spans the distance between them, with the straight edge being so oriented at the same time at least three other edges on the polygon are aligned with a like number of edges bounding the first branch at its angular terminal end, so that the timbre polygon and the first branch's angular terminal end, in assembled relation, form a pair of facing surfaces which match each other in shape and size with their respectives edges distal from said straight edge's interface with the first branch being spaced apart, thus creating a diverging air space between the facing surfaces.
9. A method for enhancing the sound of banjos having a head and a support member therefor which, in assembled relation with each other, define a generally cylindrically shaped sound chamber, wherein the support member includes a cylindrical rim with an inside surface that is substantially as wide as the sound chamber is deep, which includes the steps of: (a) bending a one piece body cut from a thick piece of paper into a three-dimensional array, the unbent body defining a main stem and first and second branches with variegated first and second angular terminal ends, respectively, wherein each of the branches forks away from the other at the branches' juncture with the main stem so as to form an asymmetrical array with an open-ended passageway, the mouth of which is bounded on one side by one of the second angular terminal end's lateral side edges at the same time the first angular terminal end's lateral side edge in closest proximity to said mouth veers away from it; (b) wherein the three-dimensional array defines first, second and third planar surfaces, each of which is intersected at least one of the other two planar surfaces, with the third planar surface being juxtaposed between the first and second planar surfaces, both of which extend in generally the same direction away from the third planar surface; (c) wherein the first planar surface, which comprises most of the first angular terminal end, intersects the first angular terminal end's lateral side edge in closest proximity to said mouth, with the first planar surface's bend with the third planar surface, as said bend extends perpendicularly to the latter lateral side edge, being kept generally free of contact with the open-ended passageway's periphery; (d) wherein the second planar surface, which comprises most of the second angular terminal end including said lateral side edge which bounds the mouth of the open-ended passageway, is disposed generally perpendicularly with respect to the third planar surface at the same time the first planar surface is inclined away from the second planar surface and the first and second planar surfaces diverge from each other as they extend, each along its respective bend with the third planar surface, in the direction of the branches' juncture with the main stem; and (e) suspending the three-dimensional array from portions of the rim's inside surface which are disposed generally uppermost when the banjo is being held in its playing position, with the array being so suspended by an elongated strip of adhesive tape, parts of which are variously affixed to the main stem and, during the array's operation, to the banjo's cylindrical rim.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
DETAILED DESCRIPTION OF THE PREFRRED EMBODIMENTS
[0037] In the drawings, an improved tone amplifier for use with a banjo having a cylindrical rim 45 that encircles the banjo's pot 50 is indicated generally by the reference numeral 10. The amplifier 10 includes a two dimensional, paper thin body 20 cut out of easily deformed, flexible cardstock or the like, at least one timbre polygon 21, a pair of staples 18, 19, and an elongated, acrylic adhesive tape segment 30, part of which is permanently affixed to the body's three-sided end 12. Prior to operation, the body 20 is suspended, within the banjo pot 50, by sticking the tape segment's free end 31 to the uppermost portions of the rim's inside surface (
[0038] Incorporated within the tone amplifier's design are many routes for sound surface waves to travel, whether they are transferred, via the adhesive tape segment 30, from the banjo's cylindrical rim 45 onto the amplifier's three-sided end 12, or are created upon impact as its body 20 is exposed to air pressure waves (audible sound) within the banjo pot 50. Because of constructive interference-related spatial differences in the intensity of the air pressure waves from point to point within the pot 50, whatever the latter of these two energy transfer modes may contribute to the tone amplifier's output is strongly dependent upon the orientation of the body 20 with respect to the banjo's head 55. Indeed, the best sound, according to experimental findings, is produced when this two-dimensional body's planar face is oriented perpendicularly to the head 55 rather than in parallel with it. Moreover, such a superior sound requires that the amplifier's timbre polygon 21 be spaced well apart from the banjo head 55 when the body's planar face is thus perpendicularly oriented.
[0039] With the timbre polygon 21 hingedly connected to the body 20 at a site on it located off-center of the body's main stem, the necessary spacing between the timbre polygon and the banjo head 55 is achieved by simply choosing, from among two possible orientations in which the tape segment's free end 31 can be placed in-line with the rim's circumference, the one which causes the timbre polygon to face away from the banjo head and not be brought close to it (
[0040] Common to at least the initial leg of the many routes that sound surface waves travel across the body 20, once these waves have been transferred onto it through the acrylic adhesive tape segment 30, is the elongated main stem 11. Appendages to this main stem, which, like it, are formed as integral parts of the amplifier's body 20, include first and second branches 15, 16 and a pair of symmetrically arrayed, three-sided arms 13, 14 (
[0041] As is characteristic of appendages onto which low frequency sound surface waves tend to diffract or bend, the laterally extending arms 13, 14 form right-angled corners with the main stem 11 and terminate in parallel far edges 23,24, respectively. There the diffracted waves grow in intensity, causing the edges 23,24 to vibrate. The rest of the sound surface waves, on the other hand, either flow around or onto a center hole 22. Located on the main stem 11 itself and approximately equidistant from each of the three-sided arms' rightangled corners, the center hole 22 presents an edge along which those waves which remain in transit on the main stem are themselves amplified.
[0042] Upon reaching the main stem's intersection with the first and second branches 15, 16, the lower frequency sound surface wavefronts once again tend to diffract or bend and, in so doing, spread out onto yet another set of main stem appendages. Left to travel straight ahead, the high frequency sound surface waves, as well as the undiffracted components of their lower frequency counterparts, are routed toward an asymmetrical array of partly circular, recessed edges 33-36 and tiny offshoots, in which the recessed edges in each contiguous pair 33, 34; 34, 35; 35,36 are separated from each other by an offshoot 37, 38, 39, respectively. Individually, the offshoots 37- 39 project outwardly into an open-ended passageway 17(
[0043] Construction of the amplifier's body 20, preferably fabricated, as a single piece, from 67 pound Neenah Paper Premium Exact Vellum Bristol cardstock with a semi-smooth finish, entails punching four i inch diameter holes in it, each of them individually centered on a corner of an imaginary square which measures approximately 5/16 inch by 5/16 inch. So centered, the holes are not tangent, but rather offset by 1/16th of an inch from each otherthe width of each tiny offshoot 37-39 at its tip.
[0044] Moreover, when the construction of the body 20 is complete, the fragments 33-36 of the four holes' annular edges still retain the same basic orientation as that which the square's four corners exhibited with respect to the main stem 11 and its appendages. Specifically, the orientation retained by these four fragments is one in which two of the square's corners that oppose each other across one of its diagonals are intersected by the same imaginary straight line which passes through the center of the main stem's hole 22 (
[0045] While each tiny offshoot 37-39 is sized to vibrate at the very high frequencies of short wavelength sound surface waves, the second branch 16 and its sharp-cornered terminal end 26 are not. Preferably differing in its transverse width from that of each tiny offshoot's tip by an order of magnitude, the terminal end 26 presents multiple edges along which lower frequency/longer wavelength sound surface waves can travel and, in so doing, gain in amplitude as two such waves at the same or similar frequencies meet each other in phase at one of these edges.
[0046] Contributing to the number of such edges is a pair of staples 18, 19 fastened to the second branch 16 in such a way that each staple's two points are in firm contact with the body's back face 60 (
[0047] Out of the four partly circular edges 33-36 which, in combination with the offshoots 37-39, line a substantial portion of the open-ended passageway's periphery, all but one of said edges is at least partly located on the first branch's side of its boundary with the passageway 17. Moreover, when the timbre polygon 21, in assembled relation with the first branch 15, is hingedly connected thereto, points on the partly circular, recessed edge 35 are situated in such close proximity to the timbre polygon's longest edge 27 that the distance between it and said points measures only about inch (
[0048] Serving a dual function in this timbre polygon/first branch assembly as both a hinge and a sound surface wave transfer bridge is a short, acrylic adhesive tape segment 32. In the preferred embodiment, tape segment 32 is a separate piece of the same material as is tape segment 30: specifically, 3M 600 Clear Acrylic Tape (Scotch High Gloss Tape). Testing has confirmed that this acrylic adhesive backed tape easily captures sound surface waves. Nevertheless, the relative positions of not only the timbre polygon's longest edge 27 and the recessed edge 35, but also the short tape segment 32 and said recessed edge matter. This is especially true in the case of the amplifier 10, designed as it is to maximize the likelihood that a high frequency sound surface wave traveling across its body 20 will gain access to the timbre polygon 21 through it longest edge 27.
[0049] In assembled relation with the timbre polygon 21, the tape segment 32, while in a longitudinally extended state, is affixed to the longest edge 27 in such a way that about one-half of the tape segment's transverse width is cantilevered over it (
[0050] The construction of the timbre polygon/first branch assembly further entails affixing an angle stop 75 to the terminal end 25. As illustrated in
[0051] Instead of a rectangle or a like regular polygon, one with the five-sided, irregular shape of the timbre polygon 21 is preferred because the latter presents an array of edges which has been proven to dramatically increase the amplification of sound surface waves transferred, via the tape segment 32, from the first branch 15 onto the timbre polygon itself. For example, as depicted schematically in
[0052] In the case of a resonator banjo, the differences in the sound of its G-string as it was being played prior to the installation of the amplifier 10 within the banjo's pot 50 and while the amplifier was so installed are displayed graphically in
[0053] The timbre polygon 21 is typically fabricated of thin carbon steel and measures approximately 0.007 inch in thickness. One inch is the approximate length of the polygon's edge 27. Running perpendicular to it and parallel to each other are two edges, one of which is approximately inch long and the other approximately inch long. The lengths of of the polygon's remaining two edges, one of which intersects said inch long edge and the other of which intersects the inch long edge, are approximately 0.76 inch and inch, respectively. Timbre polygons 21 fabricated of brass or, alternately, maple veneer measure approximately 0.010-inch and 1/32 inch in thickness, respectively, but otherwise have the same dimensions as the steel timbre polygon.
[0054] A change in the banjo's timbre or tone color can be easily achieved by replacing a timbre polygon 21 made of steel, for example, with an identically shaped one made of brass or of maple veneer or vice versa. Indeed, each such replacement polygon is preferably pre-taped along its longest edge 27 with its own tape segment 32, properly cantilevered over said edge for attachment to the first branch 15 once any timbre polygon 21 already in place there has been removed. Alternately, such a timbre polygon 21 can form a base on which one or more timbre polygons, possibly each of a different material, are stacked. Not surprisingly, as each additional timbre polygon 21 is so stacked, yet another pair of facing surfaces is created and with it one more diverging air space, thus further increasing the volume of sound in the amplifier's output.
[0055] Changes in both the banjo's volume and sound quality which result in an exceptionally beautiful sound can also be achieved by transforming the two-dimensional cut-from-cardstock body 20 into a three-dimensional array which defines three distinct planar surfaces oriented with respect to each other in such away that audible sound outputs from the tone amplifier 10 which would otherwise not intersect in air do so and, as a consequence, undergo constructive interference. By simply bending the cut-from-cardstock body 20 along first and second dashed lines 65, 66, printed on the first and second branches 15, 16, respectively, while simultaneously taking care to position one of said three planar surfaces between the other two so that both of the latter extend in generally the same direction away from it, a banjo player can readily transform the two-dimensional body 20 into the three-dimensional array. The optimum angle at which each of the two planar surfaces is so extended varies markedlyfrom one planar surface to the other and may be dependent upon the individual banjo as well. A configuration which the applicant has found works especially well in the case of his own banjo is that in which one of the planar surfaces so extendedin particular, the one formed when a substantial portion of the second branch, including its terminal end 26 and the staples 18, 19 attached theretois bent along the dashed line 66 at a 90-degree angle with respect to the planar surface so positioned, at the same time the other planar surface so extendedin particular, the one formed when a substantial portion of the first branch 15, including its terminal end 25 and the timbre polygon 21 attached theretois bent along the dashed line 65 through an angle of only 30-degrees with respect to the planar surface so positioned.
[0056] Illustrated in
[0057] Differing widely in shape and size from the narrow tape segment that is common to both embodiments 10, 40 is a much larger, clear packaging tape section 70. Nevertheless, it, like the narrow tape segment, is preferably cut from a piece of 3M Scotch High Performance Packaging Tape. Laminated onto the body 20 of the amplifier 40, the tape section 70 extends across the body's front face from the three-sided end 12 to an imaginary line which connects points on the main stem 11 that are located at the intersections between its opposing side edges and the first and second branches 15,16, respectively, wherein the tape section 70 defines a straight edge that both follows said imaginary line and spans the distance between said opposing side edges. Moreover, the tape section 70 does not cover either the main stem's central hole 22 or that part of the acrylic adhesive tape segment 30 which is permanently affixed to the three-sided end 12.
[0058] Acting primarily as a moisture barrier for a substantial portion of the amplifier's front face, the tape section 70 has also been found to improve the quality of the high tones which the amplifier 40, once its first and second branches 15, 16 have been bent to form the three-dimensional array with the 30-degree/90-degree configuration described hereinabove, produces as compared to its sound output when the body's front face is laminated with a longer clear packaging tape section (not shown)specifically, one that covers the front face from the three-sided end 12 to an imaginary line tangent to the partly circular, recessed edge 34.
[0059] As is also illustrated in the drawings, a small, nonsticky tab 71 is affixed to the distal end of each tone amplifier's tape segment 30 (