Receiving radius determination in ray-tracing sound prediction of rectangular enclosure

In this paper, the ray-tracing sound prediction for the rectangular enclosure is researched, and a new method is proposed to determine the receiving radius by sound ray density. The sound ray density can be calculated based on the initial sound ray number, volume and shape of the enclosure, and the boundary absorption coefficient. In an established enclosure, the sound ray density can be regarded to be evenly distributed statistically, so the receiving radius should be constant and have no relation to the position in the enclosure. The sound ray density is variable for different sound spaces, so the receiving radius should also be variable for different enclosures. The higher is the sound ray density, the shorter the receiving radius is, and the lower is the sound ray density, the longer the receiving radius is. A formula of calculating the receiving radius in rectangular enclosure has been deduced in this paper. The results of the experiments and predictions show that the new reception model can predict the sound pressure level (SPL) and the reverberation time T30 accurately.