The effect of receiving room sound field on the impact ball sound pressure level

Abstract

Field measurement method of heavy-weight impact sound pressure level using impact ball have been used in Korea, Japan and Canada. Also this field measurement method is discussing in ISO. Impact force and subjective responses of impact ball are very similar with child's jumping and running. In Korea and Japan is considering that using impact ball as standard impact source instead of bang machine. It is reported that heavy-weight impact sound pressure level using bang machine was varied by the sound field condition of receiving room such as sound absorption power and room volume. In this study, it is checked that impact ball sound pressure level also affected by the receiving sound field condition. Impact ball sound pressure level was measured vertically connected reverberation chamber and sound absorption power was changed by polyester sound absorption blanket with air space and glass wool. The reverberation time at 1 kHz band was changed from 10 s to 0.2 s by sound absorption material. Impact ball sound pressure level measured without sound absorption material was 58 dB in Li, Fmax, AW, but the level was 46 dB with sound absorption treatment. From this result, it is confirmed that sound field correction term may be needed in the heavy-weight impact sound pressure level measurement method using impact ball.