On the application of the Waterhouse correctionin sound insulation measurement

摘要

In the measurement based on the acoustic energy equilibrium in reverberation room, the Waterhouse correction is applied when the mean squared sound pressure averaged over the entire space must be obtained from the squared sound pressure measured in the inner region far from the room boundary. In this study, whether the Waterhouse correction should be applied or not was examined, when the sound power incident on and absorbed on the boundary are determined. The conventional equations are valid for the mean squared sound pressures averaged over the entire space which have been applied the Waterhouse correction, because the sound field in the room is not diffuse in the lower frequencies in which the correction is significant. In the determination of the sound reduction index by measuring the squared sound pressure, the Waterhouse correction should be applied to both of the source and receiving rooms. However, it is unnecessary for the case in which shape and dimension of both rooms are identical, because the correction values for both rooms are equal.