A modified method for measurement in reverberation rooms

Abstract

Unwanted noise within the built environment present a growing number of concerns for building users. Sound absorbers are frequently utilized to address these concerns. However, the characterization of their absorption coefficients continue to demonstrate challenges for high accuracy and reliability as practice requires. Recently, experimental analysis has demonstrated that the assumptions regarding the diffusivity of sound fields remain unfulfilled. Specifically, chamber-based measurement methods presume sound intensities within reverberation chambers to be isotropic, or diffuse. Diffusion equation models (DEM) have clearly shown the anisotropy of energy flows within these chamber-based measurements, especially when highly absorptive materials under test are present. This phenomenon has attracted the attention of members of the acoustical community who believe this to be the cause for well-documented inconsistencies reported by chamber-based measurement laboratories across the world. DEM offers a viable and efficient method for increasing the reliability of chamber-based measurements through the prediction of sound energy flows with reverberation chambers.