Thanks everyone for the answers.

There is good advice here. Unfortunately, either we had tried it (cut out the monitors, adjust mics, adjust certain frequencies) or it was impossible to do (practise in the space before hand). I fully agree about the soundman. They are necessary but only helpful if they are good and understand the sound the band is going after.

We do a lot of vocals so we must use mics. All other instruments have pick-ups. I know that I sound quite inexperienced and that I don't know my equipment very well but I have worked quite successfully with it all before. It was a combination of crowd noise, room config and panic on our part. We turned down the monitors comletely for much of the time until we couldn't live with not hearing ourselves. The room was so noisy the ambient crowd noise was registering on the board. Turning the monitors back on didn't seem to do more harm and helped us hear.

What is more acceptable during a gig, living with an OK but softer sound or spending a bunch of time trying to locate offending frequencies?

I guess a few things we should have thought of was to turn down the low frequencies where we could. And turn off what we weren't needing at the time. Trouble is we switch instruments a bunch.

We will have to find a very live room to practise in and try to work out some of the bugs. It sounds like from all this advice that we covered much of it. Like I said, though, we were starting to panic and when panic sets in, I start questioning everything I thought I understood or knew. Another lesson is perhaps that we don't want to play somewhere that is so crowded and noisy. On the other hand, if we get it all figured out, St. Patrick's Day should be snap.

Thanks all. Cheers. annamora