Objective and perceptual assessment of the scattered sound field in a simulated concert hall.

Acoustic scattering audibility thresholds are needed for the efficient design of performance spaces and to increase the accuracy of geometric room acoustic models. This paper focuses on the evaluation of the perceptual thresholds of the scattering coefficient through listening tests in simulated concert halls. It also deals with an investigation on the sensitivity of room acoustic parameters to scattering coefficients. A rectangular concert hall has been simulated with three prediction models, in which scattering coefficients of 0.1, 0.3, 0.5, 0.6, 0.7, and 0.9 were applied to the ceiling and walls in six different configurations. The analysis was performed comparing the results of the three-alternative forced choice listening tests and considering the objective parameters T30, early decay time (EDT), C80, and G. An increase in EDT and a decrease in C80 have been observed for increasing scattering coefficient values for all three types of software, while no similar trend was observed for the other parameters. The perceptual evaluation has shown that differences of ∼0.4, relative to an anchor value of 0.9 of the scattering coefficient, were perceived in the listening test conducted with one of the three kinds of software, while no clear differences in auralizations were perceived with the other two kinds.