US 3869954 A
There is provided an improved stringed instrument producing a clear sound without a noise. The sound board of the stringed instrument is provided with two substantially circular sound holes one of which has a diameter of two times as long as that of the other hole.
Description (OCR text may contain errors)
United States Patent [1 1 [111 3,869,954 Ito Mar. 11, 1975  STRINGED INSTRUMENT 586,032 7/1897 Hartman 84/291 2 9 l N  Inventor: Testuo Ito, 5-5-22, Shlmo-Hoya, 2 953 05 960 ewton 84,267 X Tokyo, Japan  Filed: July 31, 1974 Primary Examiner-Lawrence R. Franklin Attorney, Agent, or Firm-Robert E. Burns; [211 App! 493605 Emmanuel J. Lobato; Bruce L. Adams  Foreign Application Priority Data Oct. 16, 1973 Japan 48-11995]  ABSTRACT  US. Cl. 84/291, 84/267  Int. Cl. G10d 3/00 There is provided an improved stringed instrument  Field of Search 84/173, 267, 268, 284, producing a clear sound without a noise. The sound 84/285, 290, 291 board of the stringed instrument is provided with two substantially circular sound holes one of which has a  References Cited diameter of two times as long as that of the other hole.
UNITED. STATES PATENTS 286,524 10/1883 Bender 84/285 5 Claims, 4 Drawing Figures PATENTED MAR] 1 I975 4 F/GZZ FIG. 3
GRAPH B GRAPH-A rw nv wwmd 2'0. 4'0 MOST CLEAR SOUND EXTENT(%) 2'0 60 MOST CLEAR souwo EXTENT(%) 1 STRINGED INSTRUMENT BACKGROUND OF THE INVENTION The present invention relates to a stringed instrument and more particularly to a stringed instrument which can produce a clear sound without accompanied by noisy sounds.
From ancient times various stringed instruments, such as guitar, ukulele, mandolin, mandola, mandocello and banjo or the like, have been developed and used for playing music. Such a kind of stringed instrument is constructed as to amplify the sounds produced by vibrations of strings by a resonance body having a sound board. In general, a sound hole is provided in the sound board for introducing a sound-wave caused by the vibration of the string into the resonance body and for resounding and amplifying the introduced soundwave.
Although many attempts have been made to increase the amplification degree of such a resonance body, few investigations have been made to the improvement of the sound produced by the stringed instrument. It therefore follows that no stringed instrument capable of producing genuinely clear sound can be conventionally available. The conventionally available stringed instrument has a disadvantage in that it can not produce a genuinely clear sound but produces a sound which inevitably is accompanied with noisy sounds even when it is played by a skilled player. This disadvantage causes an unpleasant and uncomfortable effect both on the player and the audiences. After the eager pursuits for making a stringed instrument capable of producing a genuinely clear sound, I have accomplished this invention.
SUMMARY OF THE INVENTION According to this invention, there is provided an improved stringed instrument capable of producing a genuinely clear sound. The stringed instrument of this invention has a sound board provided with two sound holes of substantially circular shape. The first one of these sound holes has a diameter two times as long as that of the second sound hole. In other words, the first sound hole has an area four times as large as that of the second sound hole. Deviation in diameter of each hole shall be within i3 mm.
In a preferred embodiment of this invention, the second sound hole, which is smaller than the first sound hole, is positioned nearer to the bridge to which a plurality of strings is fastened. Also in the preferred embodiment of this invention, the lowest periphery of the second sound hole is spaced from the upper or inner end of the bridge by a few centimeters, most preferably by about 1.5 cm.
The stringed instrument according to the present invention can produce a clear and yet soft sound even when it is played by a beginner player.
DRAWINGS FIG. 1 is a plan view ofa guitar embodying this invention.
FIG. 2 is a sectional view of a sound board of the guitar shown in FIG. 1.
FIG. 3-A is a graph showing an efficiency of a stringed instrument having a sound board with two sound holes one of which has a diameter of two times as long as that of the other, whereas FIG. 3-3 is a graph showing an efficiency of a stringed instrument having a sound board provided with two' sound holes one of which has a diameter deviated by 1-3 mm from the two times length as that of the other. In these figures, a graph with reference numeral (1) shows an efficiency of a stringed instrument having a sound board provided with two sound holes the proportional diameters of which do not satisfy the relationship as defined in this invention, a graph with reference numeral (2) shows an efficiency of a stringed instrument according to this invention in which instrument the proportional diameters of two sound holes are maintained 2 l, and a graph with a reference numeral (3) shows an efficiency of a conventional stringed instrument.
DESCRIPTION The present invention will now be described in detail with reference to a guitar embodying this invention. According to this invention, two sound holes of substantially circular shape are provided on a gourdshaped or cabash-shaped sound board of wood in spaced relationship with each other at positions between a bridge and the position at which a neck is attached. The diameter ratio of the sound holes is 2 1. Three strings for producing high tone sounds and another three strings for producing low tone sounds are strained over the sound holes, one end of each string is fastened to the bridge and the other end thereof is wound around a respective peg.
When a particular string is fillipped, the string begins to vibrate and thereby to induce a sound wave which in turn, is introduced in a resonant body through the sound holes provided on the sound board and causes the vibration wave in the. air filled in the resonant body. The sound wave is thus resounded and amplified by the action of the resonant body and caused resonant vibration of the air, and comes out of the resonant body. The stringed instrument of this invention effectively prevents the generation of a harmful secondary sound wave otherwise caused in the above resounding and amplifying operation by an advantageous co-action of the two sound holes. As a result, genuinely clear and comfortable sound may be producedby the stringed instrument of the present invention.
In case where the diameter ratio of the sound holes is out of the range as defined in this invention, i.e., the deviation in diameter of each hole exceeds 1 3 mm from the proportional length ratio of 2 l, the intended object of this invention may not be attained. On the other hand, provision of three or more of sound holes reduces the advantageous effect of this invention. Only the provision of two holes retaining the interrelationship as hereinbefore defined, invites the advantageous intended effect.
PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIG. 1, guitar 1 embodying this invention has a sound board 2 to the lower surface of which a bridge 3 is transversely secured. Strings 4, three of which are strings for producing high tone sounds and the another three of which are strings for producing low tone sounds, are arranged in order between the bridge 3 and a respective peg 8 rotatably mounted at the upper end portion of a neck 7 which is securedly attached to a resonance body of the guitar 1. A circular hole 5 to 8 cm in diameter is provided under the strings 4, and a circular hole 6 of 4 cm in diameter is provided under the strings 4, the lowest periphery of the latter being spaced by 1.5 cm from the upper end of the bridge 3.
In the playing operation, the guitar having the aforementioned construction produces a genuinely clear sound of the desired tone irrespective of whether the desired sound has a high tone or low tone. It is considered that the disadvantageous amplification of the noisy sound is prevented by the provision of two sound holes one of which has a diameter of two times as long as that of the other. As far as the diameter ratio of the two sound holes is maintained at 2 1, hole area of each sound hole may be varied in relatively wide range. For example, a combination of 6 cm and 3 cm, in diameter, holes and a combination of4 cm and 2 cm, in diameter, holes give successful results.
The present invention is particularly advantageous in that a genuinely clear and yet soft sound, which has never been produced by a commonly available stringed instrument, can be produced by the use of the instrument according to this invention.
What is claimed is:
1. In a stringed instrument comprising a resonance body having a sound board provided with a sound hole and a bridge for fastening a string; and a neck secured to said resonance body at the lower end thereof and provided with a peg for straining and loosening said string at the upper end thereof; the improvement characterized in that two sound holes of substantially circular shapes are provided on said sound board at positions under said string; and that the diameter of the first sound hole is two times as long as that of the second hole.
2. A stringed instrument as claimed in claim 1, wherein the second sound hole is positioned nearer to the bridge than the first sound hole.
3. A stringed instrument as claimed in claim 2, wherein the lowest periphery of said second sound hole is spaced from the upper end of said bridge by about 1.5 cm.
4. A stringed instrument as claimed in claim 1, wherein the deviation in diameter of each hole is within 3 mm.
5. A stringed instrument as claimed in claim 1, wherein a plurality of high tone strings and a plurality of low tone strings are strained over said two sound