Improving sound diffusion in a reverberation chamber

Accurate test data of the acoustic properties of materials are critical for effective engineering noise control and general acoustic design. Acoustic test facilities are custom built to enable the measurement of various acoustic parameters such as sound reduction, sound power and absorption. However these facilities have been plagued with poor inter-laboratory results due to the lack of sufficiently diffuse sound fields. This paper quantifies the acoustic utility of a reverberation chamber, specifically with regards to its diffusion levels and analyses the effect that diffuser panels have on variations in the uniformity of the sound field. The diffusion levels are analysed using the spatial uniformity of sound pressure levels, spatial uniformity of reverberation times and the degree of time series fluctuations in an impulse response. In addition the facility has been modelled with a ray-tracing program to assess the significance that the diffuser panel orientations have on the diffusion levels of the sound field. The results from these quantifiers indicate that the orientations of the diffuser panels do not have a significant effect on the diffusion levels of the sound field