I wanted to extend my monitors out to another room for a different perspective. So I ran 2 longer cables to the other room, but after hooking them up 1 of the monitors has a hum in it (the other monitor is just fine). I thought it might be something with the 1 cable so I switched the cables to the monitors, but the exact same monitor still hums. So I thought something happened to that monitor and I went and put that monitor back in the other room with the shorter cable hooked up to it, and it doesn't hum there. It only hums when hooking it up to a longer cable run. Any ideas what might be going on?