Modifications to the diffusion model for room‐acoustic prediction

Abstract

Recently, a diffusion model has drawn attention in room‐acoustic predictions. This paper proposes possible modifications to the diffusion model to predict the reverberation times and sound pressure distributions in enclosures. While the original diffusion model [Ollendorff, Acustica 21, 236–245 (1969); J. Piacut et al., Acustica 83, 614–621 (1997); Valeau et al., JASA 119, 1504‐1513 (2006)] usually has a good performance for low absorption surfaces, the modified diffusion model, including a new boundary condition and a higher order approximation of a transport equation, yields more satisfactory results for both low and high absorption surfaces. Examples of cubic rooms, flat rooms, and long rooms with various absorption coefficients are presented for comparisons between the modified model, the original model, a geometrical‐acoustics model, and several well‐established theories in terms of reverberation times and sound pressure level distributions. This paper will discuss improved prediction accuracies by the modified diffusion model.