Directional Audio Coding (DirAC) is a parametric non-linear technique for spatial sound recording and reproduction, with flexibility in terms of loudspeaker reproduction setups. In the general 3-dimensional case, DirAC utilizes as input B-format signals, traditionally derived from the signals of a regular tetrahedral first-order microphone array, termed A-format. For high-quality rendering, the B-format signals are also exploited in the synthesis stage. In this paper we propose an alternative formulation of the analysis and synthesis, which avoids the effect of non-ideal B-format signals on both stages, and achieves improved broadband estimation of the DirAC parameters. Furthermore, a scheme for the synthesis stage is presented that utilizes directly the A-format signals without conversion to B-format.
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