After you do all that Andrew suggested....
Audyssey is as much of a pain in the ass as it is a blessing. You really need to take your time with it, and make damn sure the house (and neighbors) are quiet, and move the mic to all eight spots. Make sure to use a tri pod to hold the mic too, not YOU. It must point straight up, always. Get rid of all your pillows, blankets, whatever. If someone drives by with a hole in their muffler while in the middle of the cal session, start over.
Then after you are done screwing around with Audyssey, get your good old RS meter out and verify channel levels. You'll most likely have to set the mains/center to large, or at least move the X-over up to 80. Do not ever lower a X-over.
