Subwoofer drivers came in today! I installed one and have been enjoying the hell out of it. I've got some grounding hum though.

it's real low but ever-present. If it isn't fixed I'll drive myself crazier.
I disconnected everything from the processor except the sub and the hum remained. If I disconnect the RCA from the processor to the sub amp the hum disappears. The sub amp and processor are plugged into the same outlet. I also tried changing the interconnect. Can you tell this isn't my first ground loop problem?

. I'm open to suggestions!
This may be related but I'm not sure. This is my first home brew sub. The driver has dual voice coils but I only connected one. Is that a problem? Should I connect both? That would mean 2 channels per sub but I only have a single sub output on the Meridian 568.2.
Thanks for all of your posts recently. I will respond to then tomorrow, hopefully. Work and Maker Faire work are keeping me REALLY busy! I'm still aiming to deliver a new video this week, however!