In recent decades, round robin tests of chamber-based absorption measurements have stimulated continued debates in architectural acoustics. The standardized method traditionally applies the Sabine/Eyring formula to deduce the absorption coefficient of absorbers in the reverberation chamber. Its validity heavily relies on the diffuse field assumption. This work investigates an approach using a diffusion equation model (DEM) that can simulate both reverberant sound energies and energy flows inside reverberation chambers, particularly for random incidence absorption coefficient measurements. The diffusion equation simulations on the sound energy flows in a reverberation room further reveal inevitable violations of the diffuse field assumption around the absorber under test. Given the computational efficiency and higher order of the statistic room-acoustics foundation of the diffusion equation modeling, an approach to measuring the absorption coefficient is investigated. Without using the Sabine/Eyring formula, the proposed approach estimates the absorption coefficients by evaluating both the diffusion equation modelling results and the chamber-based measurement data. This talk also emphasizes computational efficiency of diffusion equation modeling and discusses potential significance applied to random-incident absorption coefficient measurements.
Xiang et al. (Wed,) studied this question.