Simulation of the transient and steady-state sound propagation in rooms using a new combined ray-tracing/image-source algorithm

A new method for the calculation of room acoustical impulse responses is described, which is based on two well-known computer algorithms, the ray-tracing and the image-source models. With the new method, the procedure of sieving the ‘‘visible’’ image sources out of the enormous quantity of possible sources is carried out by examination of the histories of sound particles. From the obtained list of visible image sources, the impulse response of the enclosure is easily constructed. The new method combines the advantages of the ray-tracing process, namely, the relatively slow increase of computation time with the length of the impulse response, with the accuracy inherent to the image-source model, which is even sufficient to calculate the Fourier transform, i.e., the steady-state transmission function of the room, or to convolve the impulse response with sound signals.