Speaker
Description
Late reverberation has long been assumed isotropic, i.e., showing a uniform distribution of energy over all angles of incidence. However, recent works leveraging Spherical Microphone Array (SMA) measurements and the associated spatial analysis tools have shown that the isotropy assumption is never perfectly realized. The extent and spatial characteristics of this phenomenon, and its dependence on room geometry, boundary conditions, and transducer positions, require further analysis. This work presents the results of a series of measurements conducted using the em64 Eigenmike, which supports 6th-order Ambisonic encoding, in the Espace de Projection at Ircam, a shoebox-shaped variable-acoustics hall. Spatio-temporal analysis of these measurements reveals a concentration of energy in horizontal axial and tangential modes, influenced by the room geometry. The absorptive boundary conditions induce a noticeably higher anisotropy than the reflective and diffusive ones. Furthermore, in the case of directive sources, the source orientation has a strong influence on the spatial patterns of anisotropy.