I've had both subs for a little while now and I'm amazed. with both of them hooked up audyssey actually turned them down to -2, and seems to have nailed it.
Okay. audyssey... I did upgrade to a denon x1200 (my son inherited the s 510bt). I wanted a couple extra channels, preouts for possibly adding more amplification down the road, and of course, audyssey.
There is a marked improvement in the sound coming from my system now. the bass response is much more even in almost every seating position. once again, I'm blown away. I'm super happy with my system for now, considering what I paid for everything especially. I never would have done it right without advice and guidance from you guys. not just in this thread, but also many others. I lurk and read a lot. this place is awesome and so are the people in it. Thanks for all the help and advice.