Kallinger, M.M.KallingerKüch, F.F.KüchSchultz-Amling, R.R.Schultz-AmlingGaldo, G. delG. delGaldoAhonen, J.J.AhonenPulkki, V.V.Pulkki2022-03-102022-03-102008https://publica.fraunhofer.de/handle/publica/3608992-s2.0-84866485504Directional Audio Coding (DirAC) is a well-established and efficient way to capture and reproduce a spatial sound event. In a recording room, DirAC requires four spatially coincident microphones to estimate the desired parameters, i.e., direction-of-arrival and diffuseness of sound: one omnidirectional and three figureof-eight microphones pointing along the axes of a three-dimensional Cartesian coordinate system. In most consumer applications only two dimensional scenes need to be reproduced, implying that only two figure-of-eight microphones are required. Furthermore, instead of directional microphones, arrays of omnidirectional microphones are considered for economic reasons. Therefore, it are investigated various two-dimensional micro phone configurations with respect to their usability for DirAC. Theoretical limits are derived for the correct estimation of both direction-of-arrival and diffuseness for the most suitable planar arrays. Furthermore, a way is suggested to equalize the systematic bias for the direction-of-arrival estimation, introduced by the discrete planar arrays.en621006conference paper