Studies on Impact Sound : Second Report, Mechanism of Sound Generation

Abstract

In view of troublesome nature of impact sound, a series of studies have been undertaken in order to find out a way to reduce this effect. This second report concerns the mechanism of impact sound generation when a ball collides against a plate. Simply, a ball attached with a force transducer was collided with a freely suspended square steel plate. The pulse-like contact force occurring between the ball and the plate, vibration of the plate, and impact sounds at positions near and far from the plate surface were measured simultaneously. These signals were stored in a wave memory instrument and analyzed by FFT analyzer. Frequency characteristics at four steps concerning the impact sound generation were obtained. These frequency characteristics were not affected by the size of the ball, the ball material or the impact velocity. From the results of analysis, the mechanism of generation of impact sound has been clarified.