In situ microphone array calibration for parameter estimation in directional audio coding

Directional audio coding (DirAC) provides an efficient representation of spatial sound using a downmix audio signal and parametric information, namely direction-of-arrival (DOA) and diffuseness of sound. Input to the DirAC analysis are B-format signals, usually obtained via microphone arrays. The DirAC parameter estimation is impaired when phase mismatch between the array sensors occurs. We present an approach for the in situ microphone array calibration solely based on the DirAC parameters. The algorithm aims at providing consistent parameter estimates rather than matching the sensors explicitly. It does neither require to remove the sensors from the array, nor depend on a priori knowledge such as the array size. We further propose a suitable excitation signal to assure robust calibration in reverberant environments.