A trained machine configured to input a stereo sound track and separate the stereo sound track into multiple N separated stereo audio signals respectively characterized by multiple N audio content classes. All stereo audio as input in the stereo sound track is included in the N separated stereo audio signals. A mixing module is configured to spatially localize symmetrically and without cross-talk, between left and right, the N separated stereo audio signals into multiple output channels. The output channels include respective mixtures of one or more of the N separated stereo audio signals. Gain is adjusted of the output channels into left and right binaural outputs to conserve summed levels of the N separated stereo audio signals distributed over the output channels.