How am I hearing music through speakers, if i'm not playing any?

So I have a weird situation. I can't find an answer to. If I turn my computer speakers full blast(to the point of the static/fuzz sound when you know they're turned up way too loud) without playing any music at all in my computer, I can hear the faintest music playing. I can barely make it out but it's definately music, it's songs I never heard before/don't have in my computer and it works if I plug in my headphones to the speakers also. It's freaking me out.....