Various ways to do this.

After exporting to MP3, I use Wavelab to normalize all volumes to -4 dB (Any DAW will do this). Then I play the normalized files through the PA, making notes on which songs have to come up a dB or two, or down. I revisit those songs and get a more-or-less balanced set of volumes.

Nothing worse than having a song jump out at you 6 dB too loud! shocked


Regards,

Bob