hubrad touched on it - volume. There is a point a which a room will bite back and all band members need to recognise that point and turn down. I have done a few gigs with that pissed off look on my face, not good for the punters to remember you by. two different occasions come to mind, a masonic dinner in an oak paneled room, I had read up on acoustics due to owning the PA and one suggestion was reducing the number of sources of prorogation, = to place both PA speakers together on one side of the stage - crazy - No. it worked a treat and after that my guitarist was open to any silly trick i came up with as long as he didn't have to turn down. So bass and guitar swapping sides is a good move 50/50 chance of shifting troublesome frequencies somewhere else. 2nd occasion was college dinner dance in Oxford, we had to play dinner music painfully quiet for an hour - we sounded great, after dinner tables were moved and we launched into our pop set - it was bloody awful. The hard stone surfaces were not able to handle it it it it it