1981 年 37 巻 8 号 p. 366-372
The acoustic field around a disc or a strip in diffuse sound field has been studied based on wave theory in our previous papers. But calculation of sound pressure level around the plate was very complex, and was difficult to pursue for high frequencies. To eliminate these defects approximation by geometrical acoustics is introduced jointly. By this method distributions of sound pressure level around a disc and a strip are calculated. The results are in good agreement with the experimental values, which are measured in a reverberation chamber, for wave length sufficientry shorter than the size of the plate. As a very simple and handy method another approximation is also investigated considering only the energy flow in the field. The results can predict the gross aspect of the field around the plate.