Assessment of perceptual diffuseness in the time domain

This study proposes a numerical and experimental framework for evaluating the perceptual aspect of the diffuse field condition with intended final use in music auditoria. Multiple Impulse Responses are simulated based on the time domain Poisson process with increasing reflection density. Different diffuseness conditions are realized by altering the directions of arrival of the reflected waves. This model also considers room characteristics such as the volume, absorption of surfaces, air absorption and geometrical divergence. Listening tests are performed in an anechoic 64-loudspeaker based virtual acoustic environment to examine how sensitive the human auditory system is to changes in the diffuseness condition, which factors are most crucial and which conditions are most favourable in music halls. Two types of stimuli, a music signal and an impulse response, are tested under the same diffuseness conditions. The study shows that subjective diffuseness is highly correlated to the parameters of Surround, Source Width, and Timbre, and is modelled with relevant acoustic parameters such as LG, LF and uniformity of the incident sound.