Investigations on the Diffuseness of Wave Fields in Reverberation Rooms
* Presenting author
Knowledge of the acoustic absorption properties of materials is crucial in the fields of building acoustics as well as room acoustic simulations. The random incidence absorption coefficient is measured according to the international standard ISO-354 in a reverberation room with the prerequisite of the wave field in the room being diffuse. However, studies showed high uncertainties in the method and a poor inter-laboratory reproducibility of the results. The assumption arises that these problems are in part caused by a non-diffuse wave field. A robust metric for the characterization or calibration of reverberation rooms, however, is currently lacking.In early studies, the diffuseness of wave fields in reverberation rooms has been studied with respect to the temporal structure of room impulse responses and decay curves. This, however, neglects spatial characteristics of diffuse wave fields, namely a isotropic incidence of uncorrelated plane waves and a resulting energy flow of zero. More recently, microphone arrays were proposed to investigate the spatial properties of the wave field. Different indicators and metrics for the diffuseness based on spherical array processing methods are studied with regard to their performance in the analysis of reverberation rooms.