Hi Jason. Those Aperion's in Cherry finish sure are sharp. I didn't realize they were that shiny. Sweet. I've gotta get some for my basement one day!
The center channel issue could be a few things. Area's to check are crossover setting on AVR,, Speaker Size setting on AVR and Seaker Level. Since you've received a 5.1 setup you should have received an SPL meter. That SPL meter is a vaulable tool in calibrating your system. Most likely your speakers levels aren't matching. Take some time to use the SPL meter to calibrate everything correctly.
Here is a document on using the SPL meter. http://www.aperionaudio.com/AperionU/spl.aspx
Another important thing is to get your Sub setup correctly so that it integrates seemlessly. It should sound like the bass from your Bravus is being produced by the rest of your speakers and not the Bravus. If your Bravus sounds too strong then it may need to be tweaked a bit. I would start with the owners manual becuase it does a good job explaining how to do initial setup.
Also do some reading on setting up your subwoofers
http://www.aperionaudio.com/AperionU/how_most_sub.aspx
Having your system calibrated correctly can make or break it especially when it comes to having your subwoofer blend in.. Take some time to get your AVR setup and calibrate your speakers and most importantly your sub. If you have questions we are here for you and the Aperion Gurus are just a phone call away!
Enjoy that system, I bet it will last you a long time.
PS...I've noticed a lot of people are liking All Channel Stereo on their Onkyo's. I have an Onkyo 500 series and I love multichannel music in all channell Stereo Mode...I assume it will rock even more once I get the Onkyo 805 and a pair of 5T's. Have fun!