Spherical Arrays Near Boundaries

Abstract

Summary form only given. Solid spherical microphone arrays are beginning to be used for purposes such as beamforming, sound field capture and as audio cameras. They rely on the scattering of sound off their surface to achieve their purpose. This behavior is significantly affected in the presence of boundaries (floors, walls, ceilings), and the edges and corners they form. Algorithms designed for array analysis in a free field will work erroneously in this situation. We describe adaptation of the spherical microphone analysis algorithms to constructively use the scattering off the boundaries to significantly improve array performance. We also assess the influence of walls on beamforming algorithms for regular spherical arrays. Both synthetic and experimental results are presented.