Acoustical Modeling Using a Russian Roulette Strategy

One of the problems with geometric (ray) based acoustical modeling approaches is handling the potentially large number of interactions between a propagating sound ray and objects/surfaces it may encounter. A sound ray incident on a surface may be absorbed, reflected both specularly and diffusely, be refracted and diffracted. Typical solutions to modeling such effects include emitting several “new” rays at each interaction point. Such solutions are computationally expensive for all but very simple environments. Rather than using such deterministic strategies and following these generated rays until they leave the environment or become sufficiently reduced in power that they no longer contribute to the acoustical landscape, probabilistic techniques such as the Russian Roulette strategy can be applied instead. Russian Roulette ensures the path length of each acoustic ray is kept at a manageable size yet allows for paths of arbitrary size to be explored. Here we describe the application of a Russian Roulette approach to acoustic modeling. Experimental results are presented that demonstrate the ability of Russian Roulette to provide a computationally reasonable solution to room acoustical modeling. ∗The financial support of NSERC, NCE IRIS, CRESTech and a York University President’s Dissertation Scholarship to B. Kapralos is gratefully acknowledged. The authors also acknowledge the feedback from Konstantinos Derpanis and Erich Leung.