Insufficient diffuseness is the major cause of poor inter-laboratory reproducibility of building acoustical measurements in a reverberation chamber. Many previous studies proposed methods to quantify the diffuseness in the chamber objectively, but there is no general agreement for the accuracy across these methods. Additionally, a number of measurement sample required for these diffuseness metrics is still unclear even though it significantly impacts on results. This study, therefore, aims to quantify the diffuseness of a reverberation chamber by using assorted objective metrics like spatial variation of sound pressure levels, relative standard deviation of decay rates and diffuse field factor. The measurement is also carried out with fine-resolution microphone positions and varied configurations of acoustic diffusers. With the measurement data, the effect of a number of measurement samples on the diffuseness quantification is investigated. Then, effectiveness and robustness of those objective metrics are discussed.
