Analysis of spherical isotropic noise fields with an A-Format tetrahedral microphone

Several applications in spatial audio signal processing benefit from the knowledge of the diffuseness of the sound field. In this paper, several experiments are performed to determine the response of a tetrahedral microphone array under a spherically isotropic sound field. The data were gathered with numerical simulations and real recordings using a spherical loudspeaker array. The signal analysis, performed in the microphone signal and spherical harmonic domains, reveals the characteristic coherence curves of spherical isotropic noise as a function of the frequency.