I was messing with every single cable. I relized that both the S-Video was in the TV which touches the DVD player and the Digi Coaxle was in the DVD player. I found out that whenever I unpluged the regular coaxle cable (for cable TV) the humming stopped. I had plugged in the TV cable connection in between when I was using the sub, so why did this happen? How can a coaxle cable cause this?