Monitoring volume level

The volume level of your music presents a pair of tricky problems.  (1) With only a few high-tech exceptions, the volume level can be too loud directly in front of the speakers but too quiet at points farthest from the speakers ("I can't hear the beat").  (2) And as your song alternates between its loud and quiet sections, ambient party noise usually drowns out the quieter passages, then blasts your dancers painfully during the loudest parts.  This doesn't happen in the quiet of a concert hall or at home... it's a dance party dilemma.

Because of these two problems, there's a very narrow range of acceptable volume.  Any louder and it's hurting the ears of those closest to the speakers; any quieter and it's inaudible for other dancers.  Then as most tunes decrescendo and crescendo, your music quickly goes from inaudible to painful, because of the very narrow range of acceptable volume.

Your responsibility as a DJ is to constantly monitor the volume level, lowering it during the loudest parts and raising the volume during the quiet passages.  A concert purist might complain that acoustic music doesn't do that, but here music is functional and inspirational to dancers, and must be modulated to best support the dancers.

This responsibility as a DJ might involve some self-sacrifice — foregoing the pleasure of dancing yourself.  I'll often be at a DJ'd dance and be surprised that the DJ let the music suddenly get painfully loud, or ineffectively quiet.  Sure enough, each time the DJ is out having fun on the dance floor, away from the volume control.  If you want to dance, ask someone to take over the volume control for you.  My solution, if it's one I know I'll want to dance, is to record a version in which I've adjusted the volume peaks and valleys ahead of time.

You already know this next point, but just to be thorough, the DJ often sits in an acoustic shadow behind the speakers, so the music doesn't sound as loud to the DJ as it does to the dancers.  During your first song of the night, go out onto the dance floor to make sure the sound isn't blasting those closest to the speakers, and not too quiet for those at the far end of the hall.  Check again when the floor becomes more crowded, since bodies absorb sound and change the acoustics of the dance floor.