its normally the most simple solution...
...hate to sound really nooby, but did you check simple things?
1) Did you flip your wires around? try running it a different way (parellel vs. series)
2) You do have your filter on your amp on right? I accidentally ran my sub full range when i first got it all hooked up...sounded like complete dick. Also, you do have the right filter on? i mean if you blocking out all the bass...
3) Did you contact RE? I mean, they made the subs, they might be able to help.
Try and stop thinking of the little things at look back at the big picture. Does anything seem funny to you?