Stem Separation: Mono vs Stereo Source

[tommyzai]

Has anyone noticed if there is a difference in quality between separating a mono or stereo track? Back in the early days of stereo, instruments were often hard panned. I'm wondering if this helps a separate or not. I'm wondering if some apps seem to prefer mono or stereo or maybe it doesn't matter.

Note: At present, I have the flu, my ears are ringing so loud that I barely hear anything.