DDJ-SX grounding

I am using my DDj controller at a bar and I am getting feedback from the speakers, sometimes the sound goes in and out. If I adjust the position of the decks or the audio wiring, it temporarily fixs the problem. It seems like it must be some kind of grounding issue. No other DJs, using a regular turntable setup and controllers, experience the same issue. Any ideas on how to fix please? Thanks