Effects of size and density of diffusers on scattering coefficients measured in a 1:10 reverberation chamber.

Abstract

The degree of diffusion, or scarrering coefficient, in surface materials has been known to be one of the most important aspects of the acoustical qualities of concert halls, It has also been recognized that one of the best methods, which can reduce the errors in calculating the reverberation time and other acoustic parameters through computer modeling, is to calculate the scattering coeffrcient of surface materials, Based on the suggested ISO method, which measures the random-incidence scattering coefficient of surfaces in a diffuse field, the scattering coefficients of different size and density of wooden hemispheres were measured in a 1:10 reverberation room. As a result, the 17.5cm hemisphere (real size) has the maximum scattering coefficient. It was also found that the scattering coefficient was growing higher when the coverage area increased from the center of the base plate and when the diffuse density increased until the density reached about 50%. Ceramic tiles designed by the calculations of scattering coefficients have been installde for the sidewalls of a 400-seat concert hall.