Directional Audio Coding Using Planar Microphone Arrays

Multichannel sound systems become more and more established in modern audio applications. Consequently, the recording and the reproduction of spatial audio gains increasing attention. Directional Audio Coding (DirAC) represents an efficient approach to analyze spatial sound and to reproduce it using arbitrary loudspeaker configurations. In DirAC, the direction-of-arrival and the diffuseness of sound within frequency subbands is used to encode the spatial properties of the observed sound field. The estimation of these parameters is based on an energetic sound field analysis using three-dimensional microphone arrays. In practice, however, physical design constraints make three-dimensional microphone configurations often not acceptable. In this paper, we consider a new approach to microphone array processing that allows for an estimation of both direction-of-arrival of sound and diffuseness based on planar microphone configurations. The performance of the proposed method is evaluated via simulations and real measured data.