I had the same problem with my HSU VTF-2 I figured out that it was the sub cable. It was picking up stuff from the power cables and the speaker cables. So I simply positioned my sub cable so that it rests no where near any other cable...end of hum problem.
I can't post URLs on this board for some strange reason, but go to Best Buy's website and you will find these speakers on sale for $149/pair with free shipping. Pretty hot considering these go for $300-$500 everywhere else. !
oh by the way, my house is built on concrete slab...no basement. That might have something to do with it. But still, once I turned up the volume to 50% while watching Black Hawk DOwn...I swear I thought something in my house exploded during the fight scenes.
I think there must be something else going on in your room. I have the VTF-2 in my living room, which is much larger than yours...including vaulted ceilings. I don't even turn up the volume past 30% for fear of neighbors calling the cops on me... I have the sub sitting in the right corner...