Subjective assessment of scattered sound in a virtual acoustical environment simulated with three different algorithms

A mystery around perception of music in concert halls concerns the subjective perception of diffusing surfaces situated on walls and/or ceiling. Former studies have shown that listeners prefer diffuse conditions. Hence, further investigation on the audibility of diffusion in auralized concert halls has been necessary. The following research aimed to determine the threshold of hearable differences of the scattering changes in a virtual concert hall in two different positions of the audience area: one position next to the side wall and the other one close to the rear wall. Six different scattering coefficient values s = 10, 30, 50, 60, 70 and 90 % were assigned to the interior surfaces of the ceiling, side and rear walls in simulations carried out with three different software: Odeon 10.1, Catt-Acoustic v8.0 and Raven. The analysis has been performed by investigation of subjective perception of scattered sound in three sessions of listening tests by applying the 3AFC (three Alternative Forced Choice) method where stimuli were presented to subjects via headphones using signals auralized in the three software.