Geometric signal decompositions for spatial audio enhancement

Decomposition of audio signals into primary and ambient components is useful for realizing spatial enhancements such as upmix and stereo widening. In this paper, we present several methods for primary-ambient decomposition of two-channel audio signals based on signal-space geometry. We discuss the performance of the various methods with respect to target orthogonality conditions on the estimated primary and ambient components, which cannot all be satisfied due to the need to constrain the model components to the signal subspace in light of limitations on implementation complexity.