Reproduction accuracy of Higher-Order Ambisonics with Max-rE and/or least norm solution in decoding

摘要

In sound field reproduction with Higher-Order Ambisonics (HOA), a sweet spot is formed around a reproduction point that is generally a center of spherical loudspeaker array. The conventional HOA decoding with a unique solution yields a spherical sweet spot, in which the reproduction error is less than 4% and whose radius is theoretically defined in the literature. On the other hand, it is known that Max-rE decoding or a least norm solution derived when using a larger number of loudspeakers would lead to an enhancement of reproduction accuracy. However, it is yet to be revealed how Max-rE decoding and the least norm solution affects the reproduction accuracy and the size and shape of the sweet spot, when they are individually or simultaneously applied to HOA decoding. This paper numerically investigates the reproduction accuracy of HOA with such different HOA decoding methods. The numerical results suggest that, compared to the conventional decoding method, ones with Max-rE and/or the least norm solution result in deformed or expanded sweet spot and suppression of reproduction errors outside the sweet spot.