Abstract
For the development of method of measuring floor impact sound insulation of building against heavy and soft impacts, the Floor Impact Sound Insulation W. G. (AIJ) studied various kinds of impact sources and reported these works in Feb. 1997. The W. G. continued the studies on the rubber ball impact source of about 20ms impact time, focusing on such factors as reproducibility in manufacturing and frequency characteristics of impact force. By using the ball, field measurement and subjective hearing test carried out. This paper describes the outline of these works.