Methods for stereo music source separation

Abstract

Musical source separation from stereo signals has been growing in popularity recently. Algorithms (including the author’s) and the results of a recent stereo audio source separation evaluation campaign (SASSEC) will be presented. In general, such approaches involve extracting mixing parameters from time‐frequency (T‐F) analyses of both channels. Each corresponding T‐F point of the two channels is compared and interchannel intensity differences (IID) and (in the case of stereo mixing), interchannel phase differences (IPD) are computed. A histogram of signal power in the IID and IPD space is constructed, with sources showing strong peaks at the locations of their mixing parameters. Masks are then created for each potential source, corresponding to T‐F points that share common mixing parameters. These masks are applied to the T‐F analysis and resynthesized as probable sources. The underlying assumption of such systems is that of W‐disjoint orthogonality, that is, T‐F points of the sources do not overlap. In music, however, this is rarely the case, as common musical intervals often contain overalapping harmonic ‘‘collisions.’’ The use of an exponentially damped sinusoidal model, that in limited cases has the ability to resolve very closely spaced, beating, sinusoids is explored as a means of separating harmonic collisions.