In a PA/live playback situation, how to deal with temporary and sudden increase in signal? Situation is as follows: a mic is in the middle of the room and nearby a person talks and sings. Now and then audience which is standing very close - 2 meters away in a semi-circle joins in an sings loudly thereby increasing the signal volume suddenly - this causes clipping on main set of speakers and also the broadcasted stream which is taken off main mix sounds garbage.
How to deal with this? manually adjust when audience joins in and leaves or are there any tricks like reducing gain level on mic?