ASA 125th Meeting Ottawa 1993 May

4aAA9. DISC project: Auralization of virtual environments and the DIrectional Scattering Coefficient.

Peter D'Antonio

RPG Diffusor Systems, Inc., 651-C Commerce Dr., Upper Marlboro, MD 20772

Accurate prediction of a room's impulse response requires the appropriate directional scattering coefficients, as well as computational algorithms, which utilize these data in modeling programs. The directional scattering coefficients define how sound interacts with the various absorbing, reflecting, diffusing, and diffracting surfaces in a room, as a function of the incident direction and frequency, sample size, mounting, and observation direction. Unfortunately, these data and algorithms do not exist. The acoustics community is now preparing to meet the challenge of augmenting random-incidence absorption coefficients and establishing a database of DIrectional Scattering Coefficients (DISC) for all commonly used architectural materials, in a new basic research initiative called the DISC project. The goals of the DISC project are as follows. (1) Design and implement computer-controlled automatic testing instrumentation and facilities to experimentally map the full-spectrum backscattered hemisphere for all commonly used architectural materials for all angles of incidence and various sample sizes and mountings. (2) Develop a geometrical convolution algorithm that can be used with the image model to utilize directional information and provide n-bounce impulse responses, which agree with experimental measurements within accepted error limits, as judged by auralization test. (3) Conduct subjective perception auralization studies with headphones and in an acoustically optimized loudspeaker listening environment.