chas ... great to have you back ... hope your physical pain ends a lot sooner than your 'mental' pain ...
About your question ... I use an INexpensive alesis mixer with L/R outs ... from my kb, I can pan voices to the left, right, or center... using two powered speakers,one on each side of me, I can separate the L from the R, so when I have a voice panned to the right I hear it from that speaker, etc ... bass and drums are panned to center so they come out both speakers ...
That being said, this sounds GREAT to my ears, but how much separation (if any) the audience is hearing depends on where they are located, I guess ...

I'm sure others will give you more on this ...

t.