It's not the receiver, but the placement of the speakers most likely. Try moving them closer to the wall if possible. That should give you some additional bass by boosting baffle step. The speakers are about 3 db higher in the upper range so you might try knocking them down on the treble control a notch.I really like the Ascends. Overall, I think the system is bit on the bright side - but I would attribute that sound more to my Panasonic receiver than the Ascends.
I have no complaints about the Ascends at all -