They'll usually put when doors open on the ticket or the advertisement for the specific show. I believe that Atlanta has a noise ordinance, and I think that it says 11:30 p.m. is the time you can't hear music from outside. I may be off about that though.
Main show usually starts at 8 PM performance ends 10:30 to 11 PM. Don't know if bars stay open much longer after that.
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