I've been the house sound guy at a local club for a few months now. It's a
fairly easy gig, and I've had the chance to work with some really great
players, but these things drive me nuts on a pretty consistent basis:

1) Guitar players that don't have a guitar and/or speaker cable with them and
expect the club to provide these, the only thing worse than this is the
laptop/keyboard guy that doesn't have a 1/8" to 1/4" cable to go from the
laptop to the DI. I have noticed that most of the pro guys are bringing their
own high quality audio interfaces and DIs with them.

2) Singers that create feedback by cupping the mic or pointing the mic directly
at the floor wedges. I did see a vocalist use the mic cupping technique to
achieve an interesting sonic effect once, so I'll give that guy a pass. Also,
the singers that bring the mic with them out into the crowd in front of the
mains - that really irritates me.

3) The stage volume thing. I like it loud too, I'm a rock and roll kind of
guy, but some of these bands are out of control with the full stacks. At least
give me a fighting chance to make you sound good.

4) Vocalists that drop the mic on stage, or better yet, out in the crowd for
dramatic effect. Just stop.

Does anyone have anything else to add to this list? 
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