I have my fronts connected to a pair of mono blocks for the last 6 months. About a week ago I noticed a hum coming from the fronts. It goes away if I powerdown the amps. I haven't dones a lot of troubleshooting yet, just wondering if anyone knows what could cause this. Nothing has changed with my system. I did add a wireless router to may computer in the next room and got a black lab puppy. Other than those 2 things...nothing else has changed. Oh yeah, I'm having an addition built on to the house. Thx in advance. D. Kemp