Directional distribution of acoustic energy density incident to a surface under reverberant condition

Abstract

Most acoustic measurements are based on the assumption of ideal conditions. One such ideal condition is a diffuse and reverberant field. In practice, a diffuse sound field cannot be achieved in a reverberation chamber. Particularly, the directional diffusion, which means the uniform angular distribution of incident energy onto surfaces, cannot be satisfied. Angle dependence of incident energy density was simulated by the phased beam tracing method by changing room shapes and source positions. It was found that acoustic energy density decreases with the angle of incidence. The shape of the averaged angular distribution is similar to the Gaussian distribution. Long distance between the source and the target surface highlights the normally incident components. To get a fairly uniform distribution, the acoustic centre of the source should be close to and aligned with the periphery of the absorption sample.