Monitors are sent a signal from aux send channels of a Onex 32 Mackey mixer through a 16/4 100' snake cable and coupled to the monitor with a ground loop isolater. The monitors (all 4 of them)make random poping/crackling noises and at times a constant crackling noise similar to a machine gun. Turning lights on or unpluging/pluging other electrical components also cause crackling noises in the monitors.