A simple iteration scheme for the computation of decay constants in enclosures with diffusely reflecting boundaries

This paper describes a procedure for the exact determination of the decay constant and hence of the reverberation time of enclosures with diffusely reflecting boundaries. It is based on the integral equation which describes the energy propagation in such rooms under the condition of exponential decay. In contrast to Gilbert’s well-known method, the decay constant is determined by an iterative solution merely of that integral equation. Some typical results for rectangular rooms are presented. Depending on the distribution of sound absorbing areas, considerable differences between reverberation times after Sabine’s equation, on the one hand, and the present method, on the other, are observed. Furthermore, the question to what extent the applicability of the procedure is restricted by the assumption of diffuse wall reflections is discussed.