Influence of Sound Scattering on the Reverberation Time of a Shoebox Auditorium Using Room Acoustics Modelling

This paper focuses on examining the impact of introducing sound scattering in room acoustic modelling, using a ray tracing approach. A parametric study is conducted on a simplified shoebox auditorium, isolating distinct factors, such as the average absorption of the room, room geometry, volume of the space or the introduction of prismatic-shape diffusers. Diffusion is considered by assigning a scattering coefficient (s) to the surfaces, except in the analysis of a prismatic diffuser, which is modelled using a geometric approach. Changes in the reverberation time are analyzed alongside their corresponding just noticeable differences (JNDs). It was found that sound scattering can reduce reverberation time, especially in rooms with parallel walls, but only when sufficient and well-distributed sound absorption is present. Geometric modifications that remove parallelism reduce flutter echoes and can decrease reliance on scattering. Volume scaling of a room has negligible perceptual influence on sound scattering, whereas modifying room proportions offers a stronger influence on reverberation perception. Prismatic diffusers provide efficient geometric diffusion, achieving outcomes comparable to flat surfaces assigned with medium sound scattering coefficients.