It probably also depends on the channel separation for the individual instruments in the final mix and any effects applied. A stereo chorus effect on one of the

It probably also depends on the channel separation for the individual instruments in the final mix and any effects applied. A stereo chorus effect on one of the instruments can really interfere with the separation from other instruments from what I can tell. Piano (or various keys), organ and some guitars (with effects) have a lot of frequency overlap. The model struggles there.