Reply to Static feed back coming from speakers when playing on stereo

I'm new to this so don't know much, but I have a numark mix track pro that I just got trying to learn how to do, but I've noticed when I play on stereo I get a lot of static from some songs but when I switch it to mono it sounds a little more cleaner, can it be the songs, speakers (I have it hooked up to little stereo) any advices tips will be helpful, but thanks