Ambisonic Decoding with and without Mode-Matching: A Case Study Using the Hemisphere
Franz Zotter, Hannes Pomberger, and Markus Noisternig
Accurate decoding and most notably mode-matching has always been a matter of concern within the Ambisonics community; it can be further expected to play a major role in future discussion and research. Specifically, ambisonic decoding by mode-matching attempts to perfectly reconstruct incident sound fields using a surrounding spherical arrangement of loudspeakers. This reproduction is valid locally within a bounded central area, the sweet-area. Surprisingly, many (experienced) listeners have reported good reproduction quality and fair localization accuracy of real-world Ambisonics systems even outside this sweet area. Hence in practice, mode-matching decoding performs better than expected from theory, but it frequently poses numerical problems for incomplete or non-uniform spherical loudspeaker arrangements. To cope with these issues, this article presents, discusses, and compares several alternative Ambisonics decoding strategies with and without mode-matching in terms of simple quality criteria.