Zo, the head scratcher is that it's not a hum in the low end, rather a buzz in the high end. I have Rocket RS1000's and its coming from the very top speaker in the array.

Doug your probably right. Thing is that the 990 is plugged into the power distribution center, and the Amp is not, rather to the wall with a surge block between the outlet and the plug. Since I was at it I figured why the hell not, ya know...