| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase bent strength and shear strength, remove mental pressure of 'break', and allow sufficient performance, by fixing same kind or different kind of thin material to the central part of a recess in the rear surface of a marimba sound disk such that the material crosses the longitudinal direction of the sound disk. SOLUTION: A marimba sound disk 1 is adjusted in musical interval while depth of a recess 2 is increased. The recess 2 is deeper with lower-pitched sound, and the central part becomes thinner. The thinnest thickness is about 4-5 mm. Therefore, while a musician plays it with a drumstick, the marimba may break. A same kind or different kind of thin material as a reinforcement 4 is fixed to the central part of the recess 2 in the rear surface of the marimba sound disk 1 such that the material crosses the longitudinal direction of the sound disk. Thus, bent strength and shear strength are increased. A vibration state when the marimba sound disk 1 is played provides an amplitude and dumping very close to those when the reinforcement 4 is not mounted, by adjusting the size of the reinforcement 4 even when the reinforcement 4 is mounted.</p> |
