[pinky]

I've been noticing lately that after i've recorded a song and mixed it, when I'm in the mastering stage and I use the Waves Shuffler and I invert the phase on one of the channels (L or R) I get a lot more space in my mix (more 3d sounding) but I also get some boomyness which I just drop between 125-500hz on an eq and it takes that boom out. So I really like how it sounds and so does everyone else i show it to.
I've done stuff just with acoustic guitar and vox (at seperate times 1 mic each) so I'm pretty sure its not a phase problem. It also doesn't just sound good on my monitors, it sounds good everywhere on every consumer system its on.

What's going on here? Is it my reverb aux track that I send the tracks to?
I'm mastering ITB obviously, and for these particular sessions I'm talking about I'm putting the mastering plugs on a mix bus and then sending them to the master track.

Could it be that its pre master fader? It doesn't seem to me like that would be it.

I also can't do it with a mix that has very many tracks because it makes some stuff sound weird that I recorded in phase with 2+ mics and have them panned. Unless I invert that tracks phase as well.

Obviously I want that sound but it seems I'm getting it in a way that isn't necessary and I could be getting it more directly and not cause phase problems by switching the phase on the shuffler plugin.