Tone-balancing element

Abstract

A laminated piano soundboard includes a treble and bass bridge for transmitting vibrations from the piano strings and a plurality of spaced-apart ribs for localizing the vibrations at the center, prime resonating area of the soundboard. Since the laminated character of the soundboard tends to inhibit localization thereby adversely effecting its tonal quality, a tone-balancing element is provided for assuring enhanced resonance.

Claims

1. A piano soundboard assembly comprising: a resonator board for producing standing sound waves; a plurality of ribs mounted to one side of said board in substantially parallel arrangement; and a planar, triangular tone-balancing element mounted to the opposite side of said board, said tone-balancing element being disposed in a corner region of said board with the longest edge generally at a right angle to the longitudinal axes of said ribs, whereby to locate standing sound waves generally centrally of said board. 2. A piano soundboard assembly according to claim 1 wherein said resonator board is substantially rectangular in shape for defining a substantially similarly shaped resonating surface area and wherein said tone-balancing element forms a right triangle having a hypotenuse side and first and second sides extending from the right-angled vertex thereof, said first and second sides being positioned parallel to intersecting joined edges of said resonator board. 3. A piano soundboard assembly according to claim 2 wherein said resonator board includes triangular support means mounted to three of its four vertices, said support means converting the substantially rectangular resonaTing surface area of said resonator board to a substantially hexagonal resonating surface area. 4. A piano soundboard assembly according to claim 2 wherein the hypotenuse side of said tone-balancing elements includes a plurality of scallops which further localize said standing sound waves. 5. A piano soundboard assembly according to claim 4 wherein said scallops are equally laterally spaced along the hypotenuse of said tone-balancing element, alternatively over and between said rib members. 6. A piano soundboard assembly according to claim 1 wherein said resonator board comprises a plurality of wood plies.
United States Patent Andersen [541 TONE-BALANCING ELEMENT [72] inventor: Clifford W. Andersen, De Kalb, ill. [73] Assignee: The Wurlitzer Company, Chicago, Ill. 22 Filed: June 1, 1970 [21] Appl. No.: 41,978 [52] US. Cl ..84/192 {51] Int. ..Gl0c 3/06 [581 Field oiSearch ..84/192,194,189,l93, 184, 84/187 [56} References Cited UNITED STATES PATENTS 777,939 12/1904 Clemons ..84/ 192 1,747,307 2/1930 Leland et ...84/192 2,469,522 5/1949 Sauerland ..84/ 192 Feb. 15, 1972 3,248,990 5/1966 Bolin ..84/1 89 3,444,771 5/1969 Taguchi ....84/ l 94 3,459,091 8/1969 Taguchi ..84/ l 92 Primary Examiner-Richard B. Wilkinson Assistant Examiner-John F. Gonzales Attorney-Olson, Trexler, Wolters & Bushnell [57] ABSTRACT A laminated piano soundboard includes a treble and bass bridge for transmitting vibrations from the piano strings and n plurality of spaced-apart ribs for localizing the vibrations at the center, prime resonating area of the soundboard. Since the laminated character of the soundboard tends to inhibit localization thereby adversely efiecting its tonal quality, a tonebalancing element is provided for assuring enhanced resonance. 6 Claims, 7 Drawing Figures PATENTEUFEB 15 I972 sum 2 OF 2 iiiii/""'"" W TONE-BALANCING ELEMENT SUMMARY OF THE INVENTION DISTINCTION OVER THE PRIOR ART AND OBJECTS A piano soundboard is a resonator to which the vibrations of piano strings are transmitted for producing tonal qualities. In the past, such soundboards were made out of solid boards which were selectively tapered and provided with transversely extending rib members for localizing the vibrations in a manner which would most enhance the tonal qualities. More recently, some pianos have utilized laminated rather than solid soundboards. However, it has been found to be impossible to satisfactorily taper a laminated board. Therefore, in the past, such laminated soundboards were characterized by poor tonal qualities. Accordingly, a general object of the present invention is to provide a new and improved laminated soundboard which is characterized by greater tonal qualities than those of the prior art. Another object of the present invention is to provide a laminated soundboard which vibrates in a controlled fashion. A more particular object of the present invention is to provide a novel tone-balancing element to be used with a laminated soundboard for controlling the standing sound waves thereof. Yet a more particular object of the present invention is to provide a tone-balancing element which attenuates the standing sound waves of a soundboard and localizes them in the center of the soundboard. These and other objects and features of the invention will become more apparent from a reading of the following descriptions. The above objects are achieved and the disadvantages of the prior art are eliminated by providing a piano soundboard comprising a laminated resonating board which is preferably made from three-ply mahogany and which is coupled to the strings of a piano through a treble bridge and a bass bridge. A plurality of ribs and a unique tone-balancing element are selectively mounted on opposite sides of the resonating board for attenuating the standing sound waves of the board and localizing them in a manner most effective for producing the highest tonal quality. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a front elevational view of a soundboard constructed according to the invention; FIG. 2 is a front elevational view of the soundboard of FIG. .1 coupled to the piano strings of an upright piano; DETAILED DESCRIPTION Referring now in detail to the drawings, specifically to FIG. I, a piano soundboard constructed in accordance with the present invention is indicated generally by the reference numeral 10. The soundboard comprises a substantially rectangular laminated resonator board 12 which is preferably fashioned from three plys of mahogany wood and which is coupled, through a treble bridge 14 and bass bridge 16, to the vibrating strings of a piano for transmitting a series of vibrations to the board 12 and thereby producing standing sound waves. A plurality of longitudinal rib members 18, positioned on selective areas of the back side of the resonator board, provide rigidity to those areas so that the remaining surface thereof may freely vibrate for most advantageously localizing the standing sound waves. The bridges and rib members are preferably mounted to the resonator board by a resinous plastic waterproof glue so that the board is not impregnated with moisture. Such moisture has been found to reduce the tonal quality of a soundboard. The surface of resonator board 12 is selectively tapered in the same manner as the prior art solid boards, but due to their laminated characteristic, the various tapered sections do not exhibit a predictable quality of sound which is otherwise found in solid resonator boards. In this regard, it has been found that a plurality of conventional rib members alone, do not properly localize the standing sound waves. Accordingly, a carefully sized and shaped tone-balancing element 20, selectively glued to the front or string-connecting side of the resonator board attenuates the standing sound waves and localizes them at the center where they have been found to produce the best tonal quality. Turning to FIG. 2, an upright piano 22 utilizing the soundboard 10 includes a vertically mounted substantially rectangular housing or frame 24 supporting the soundboard so that the treble and bass bridges extend out beyond the frame for engagement with the vibrating portions of a plurality of treble strings 26 and bass strings 28 respectively. The treble strings, which are connected to the top of frame 24 by a plurality of string pins 30, extend down and slightly to the left, as viewed in FIG. 2, so as to pass over and engage the treble bridge 14 and thereafter terminate at a bridge 32 which is mounted to the bottom and one side of the frame and which extends across the soundboard slightly below the treble bridge. A plurality of string pins 31 secure the strings to the bridge 32. The bass strings 28, which are connected to the top of frame 24 by string pins 34, extend downward, slightly to the right and over the treble strings for engagement with the bass bridge 16 and are thereafter secured to the bottom of the frame by a group of string pins 36. Vibrations are conventionally imparted to the strings by an action mechanism (not shown) which is actuated by a corresponding key of the piano keyboard. These vibrations, which include differing harmonic frequencies depending upon the length, diameter, tension and density of the strings, are transmitted to the resonator board through the bridges and develop a standing sound wave. Both the rib members 18 and the tone-balancing element 20 provide attenuation and localization, so that the sound waves produce an enhanced tone. Referring now to FIGS. 3 and 5, the rib members 18 are equally laterally spaced on the back of resonator board 12 and are aligned substantially perpendicularly to a line which bisects the upper leftand lower right-hand corners of the board, as viewed in FIG. 3. The rib members are of varying length so as to extend substantially from one edge of the board to the other, the members being relieved on common ends to form beveled shoulders 38 which are sized in accordance with their respective positions on the resonating board to constrain or localize the transmitted vibrations in areas designated by the reference numeral 40 which lie therebetween. Each of the members tapers downward, at a slight angle, from the uppermost point of its shoulder so that a beveled shoulder may be eliminated at the other end. As stated above, rib members 18, when constructed in the aforementioned manner, do not alone localize the vibrations in the desired fashion. Absent the tone-balancing element 20, there would be a tendency for most of the vibration to develop at the upper right-hand corner of the board as viewed in FIG. 3 It should be noted that three of the four vertices of frame 24 include integrally connected triangular extensions or supports 42 which convert the effective resonating area from a rectangular to a hexagonal area. This, in turn, further directs the vibrations to the center. Returning to FIG. 1, the tone-balancing element 20 comprises a flat, preferably laminated wafer, as seen in FIG. 4, in the form of a right-angle triangle having a hypotenuse 43 joining remaining sides or legs 44 and 46 which meet at the rightangle, the side 46 being of slightly greater length than that of side 44. The tone-balancing element is positioned on the resonator board so that its right-angled vertex is positioned adjacent the upper left-hand vertex of the resonator board, as viewed in FIG. 1, so that the hypotenuse 43 extends perpendicular to the rib members 18. This arrangement prevents the transmitted vibrations from localizing adjacent the corner of the soundboard and attenuates the standing sound waves for redirecting them toward the center of the resonator board, thus achieving the highest quality of piano tone. Turning to FIGS. 6 and 7, there is shown a modified tonebalancing element 50 which also takes the form of a rightangle triangle having a hypotenuse side 52 joining two perpendicular sides 54 and 56 and which is positioned in the same location as that of tone-balancing element 20. However, the hypotenuse side thereof includes a plurality of equally laterally spaced semicylindrical scallops 58 which further calize the standing sound waves developed in the resonator board. Specifically, as seen in FIG. 6, the scallops are positioned, alternatively, over and between underlying rib members 18 so that, as the vibrations of the resonator board tend to develop, the scallops tend to attenuate them and redirect them towards the center thereof. While particular embodiments of the invention have been shown, it should be understood, of course, that the invention is not limited thereto since many modifications may be made. It is, therefore, contemplated to cover by the present application any such modifications as fall within the true spirit and scope of the appended claims. The invention is claimed as follows: 1. A piano soundboard assembly comprising: a resonator board for producing standing sound waves; a plurality of ribs mounted to one side of said board in substantially parallel arrangement; and a planar, triangular tone-balancing element mounted to the opposite side of said board, said tone-balancing element being disposed in a corner region of said board with the longest edge generally at a right angle to the longitudinal axes of said ribs, whereby to locate standing sound waves generally centrally of said board. 2. A piano soundboard assembly according to claim I wherein said resonator board is substantially rectangular in shape for defining a substantially similarly shaped resonating surface area and wherein said tone-balancing element forms a right triangle having a hypotenuse side and first and second sides extending from the right-angled vertex thereof, said first and second sides being positioned parallel to intersecting joined edges of said resonator board. 3. A piano soundboard assembly according to claim 2 wherein said resonator board includes triangular support means mounted to three of its four vertices, said support means converting the substantially rectangular resonating surface area of said resonator board to a substantially hexagonal resonating surface area. 4. A piano soundboard assembly according to claim 2 wherein the hypotenuse side of said tone-balancing elements includes a plurality of scallops which further localize said standing sound waves. 5. A piano soundboard assembly according to claim 4 wherein said scallops are equally laterally spaced along the hypotenuse of said tone-balancing element, alternatively over and between said rib members. 6. A piano soundboard assembly according to claim 1 wherein said resonator board comprises a plurality of wood plies.

Description

Topics

Download Full PDF Version (Non-Commercial Use)

Patent Citations (6)

    Publication numberPublication dateAssigneeTitle
    US-1747307-AFebruary 18, 1930Laminated Materials Company LtSounding board
    US-2469522-AMay 10, 1949Hardman Peck & CompanyPiano soundboard
    US-3248990-AMay 03, 1966Bolin Gustav George ArnePiano tone producing structure
    US-3444771-AMay 20, 1969Nippon Musical Instruments MfgPiano soundboard assembly with auxiliary board
    US-3459091-AAugust 05, 1969Nippon Musical Instruments MfgArrangement for fitting a sounding board assembly in a piano
    US-777939-ADecember 20, 1904Charles B ClemonsPiano sounding-board.

NO-Patent Citations (0)

    Title

Cited By (4)

    Publication numberPublication dateAssigneeTitle
    CN-102750936-AOctober 24, 2012胡坤灵Piano allow and manufacture method thereof
    CN-102750936-BMay 07, 2014胡坤灵Piano allow and manufacture method thereof
    US-4248124-AFebruary 03, 1981The Wurlitzer CompanyPiano soundboard
    US-5320018-AJune 14, 1994Fandrich Delwin DSound board assembly comprising a cut-off bar having an acoustically free end