The stadium has a new Peavey sound system - PV 14 mixer, PV 2600 amp, PV 1/3 EQ into 3 Impluse 1015 speakers. The issue to ask for help is the sound volume level sometimes will reduce by itself. When the channel slider is pushed up to re-reached the desired volume level, the volume when then bounch back higher to the level appropriate for the level of the slider. This has happened using 2 different channels on the mixer board. A computer is used to play mp3 songs into the mixer with a RCA cable to a 1/4" input jack on the mixer. Have used both the headphone outout jack and also the USB output with a Turtle Beach Audio Advantage Micro in the USB jack of the computer into the mixer 1/4" jack - same result from both computer outputs. Two different cables have been used from the computer to the mixer with same result. Have not tried yet using the CD player included in the system to see if the volume reduction takes place when not using the computer for input. The computer is a 1.86 GHz laptop with 1 GB of RAM on XP only running the sound play program. Might there be any potential issues with the computer or sound system that would cause this undesired automatic reduction of sound volume? What additional testing could be done to narrow the issue down?