Wavelet-based spatial audio framework
This work addresses spatial audio quality issues for audio engineers and VR/AR applications, representing an incremental improvement over existing Ambisonics methods.
The paper tackles the limitations of low-order Ambisonics, such as poor source directivity and small sweet-spot, by proposing a novel spatial audio framework that replaces spherical harmonics with spherical wavelets, developing a complete encoding-to-decoding chain and showing it can be optimized for irregular loudspeaker layouts.
Ambisonics is a complete theory for spatial audio whose building blocks are the spherical harmonics. Some of the drawbacks of low order Ambisonics, like poor source directivity and small sweet-spot, are directly related to the properties of spherical harmonics. In this thesis we illustrate a novel spatial audio framework similar in spirit to Ambisonics that replaces the spherical harmonics by an alternative set of functions with compact support: the spherical wavelets. We develop a complete audio chain from encoding to decoding, using discrete spherical wavelets built on a multiresolution mesh. We show how the wavelet family and the decoding matrices to loudspeakers can be generated via numerical optimization. In particular, we present a decoding algorithm optimizing acoustic and psychoacoustic parameters that can generate decoding matrices to irregular layouts for both Ambisonics and the new wavelet format. This audio workflow is directly compared with Ambisonics.