Exterior-interior 3D sound field separation using a planar array of differential microphones

Abstract

Sound field separation using spherical microphone arrays was recently introduced and has many applications, however, it is inconvenient to implement in realistic environment. In this paper, we propose a solution to separate 3D interior and exterior sound field by using a planar array of differential microphones. The even coefficients and odd coefficients of sound fields are separated in two different ways due to the properties of associated Legendre functions. Simulation shows this practical geometry has a good performance on interior and exterior sound field separation in both noiseless and noisy environments. We also evaluate the reconstruction accuracy of separated sound fields on different spherical surfaces.