Improvements to the Matching Projection Decoding Method for Ambisonic System with Irregular Loudspeaker Layouts

The Ambisonic technique has been widely used for sound field recording and reproduction recently. However, the basic Ambisonic decoding method will break down when the playback loudspeakers distribute unevenly. Various methods have been proposed to solve this problem. This paper introduces several improvements to a recently proposed Ambisonic decoding method, the matching projection method, for uneven loudspeaker layouts. The first improvement is energy preserving; the second is introducing the "in-phase" weight, and the third is introducing partial projection coefficients. To evaluate the improved method, we compared it with the original one and the all-round Ambisonic decoding method with a 2-dimension unevenly arranged loudspeaker array. The result shows our method greatly improves the original method where the loudspeaker arranges very sparsely or densely.