Sound field correction of receiving room on heavy/soft impact sound

摘要

Floor impact sound in apartment building became one of the major social problems in Korea. Heavy/soft impact sound source such as rubber ball and bang machine is used in Korea, Japan and Canada. Heavy/soft impact sound was being measured in various sound field conditions from a reverberation chamber for a development stage to in-situ condition in apartment buildings. For the measurement of heavy/soft impact sound measurement, maximum sound pressure level in each 1/3 Octave band was measured without any receiving sound field correction. It was known that maximum sound pressure level of intermittent noise was not affected by the receiving sound field condition. However, it was reported that heavy/soft impact sound pressure level was changed by the change of receiving sound field in reverberation chamber and standard test facility, which is similar with the living room of an apartment unit. There are several kinds of measurand considering receiving sound field condition. One is the standardized maximum sound pressure level in ISO 16032, another is normalized maximum sound pressure level, and the other is NRC method. In this study, results of heavy/soft impact sound pressure level measurement using rubber ball in various sound field condition, with the change of sound absorption power was corrected with three kinds of receiving sound field correction method. Standardized and normalized maximum sound pressure level and NRC method were applied in order to select proper correction method. Among the three kinds of correction method, normalized maximum sound pressure level made the level difference larger. From the results of receiving sound field correction method, it was concluded that the NRC method is the proper correction method.