Folks often discuss whether or not to use any compression or limiting on the Master track of a set used for performance. (There’s no one right answer to this.)
For a set where some of the material is already fully mixed and mastered, the answer is mostly no. For my current hybrid DJ set, I keep a Limiter in my master track set up like this:
The point of the Limiter in this situation is to save my bacon if I make a mistake – it will only kick in if there’s way too much sound coming out of the tracks in my set. Otherwise, the Limiter is totally inactive.
Gain is set to -6 which just reduces the overall level going into the Limiter. Make up the gain using the volume control on your audio interface. You’ll need to experiment with your set to find out the ideal setting for Gain. Turn it down until you almost never see the gain reduction meter move.
Lookahead is set to the lowest value. This control acts like an attack control – lower lookahead slows down the Limiter’s attack, preserving more of the transients in the case that it does act.
Release is turned all the way down so the Limiter disengages as quickly as possible.