Seminar by Simon Belloncle

Study of spherical microphone array networks for large scale capture and analysis of acoustic fields

Acoustic imaging is usually performed using a single array of omnidirectional microphones distributed on a planar, cylindrical or spherical geometry. In the case of spherical microphone arrays (SMA)s, the analysis can be done in the spherical harmonics (SH) domain, as developed in the field of Ambisonics. However, practical implementations of the latter approach are often constituted of a smaller number of microphones compared to planar arrays, which implies limited spatial resolution and bandwidth. In order to overcome this constraint, the presented work explores the use of multiple SMAs for the capture of their respective local sound field, and discusses on how to process them globally for acoustic imaging purposes. Different processing strategies are evaluated in simulation for a few network geometries and validated in the frame of laboratory measurements based on the use of 5 SMAs distributed on a plane, at the vertices of a pentagone. Acoustic imaging results are compared with a conventional planar microphone array constituted of 81 microphones.