Need rear speaker help

Assuming that everything was balanced useing your AVR auto setup w/mic or by you with an SPL meter, did you try raising the rear surround volume slightly?

Out of curiosity is it equally a problem in all surround modes?

I have no experience with True HD so all I can do is note that .8dB is not a big change. Detectable with pink noise maybe, but not huge. I would try a larger boost of up to 3dB (a change that most can easily hear).

Perhaps someone else can jump in.

When you ran the auto setup did you run it from the center of the room or from the main listening possition ?
Because to me it sounds like you setup from the center of the room when the ideal place is the "Sweet spot' in the center of the room but in the first row if you have several rows of seating.
And finally get an spl meter to balance everything properly, Here are some links.
http://www.audiophilia.com/hardware/spl.htm
And here is the meter:
http://www.bswusa.com/proditem.asp?item=SLM100

Well, sorry to tell you but I also have the 3806 and unfortunately it is not thx select2 or ultra2 certified so it doesn't have the thx ASA(advanced speaker array). You should have done it by dolby recommends it. In the manual for the 3806 it shows you how you should place them and it is just like dolby does it so I hate to tell you this but you should spread those rear speakers out....alot more work since they are in-wall but thats what you should do. You could leave them where they are and buy a THX select2 or ultra2 receiver but of course that is more expensive unless you can return the denon etc...

ps...what surround mode do you use for sports on the denon? you said 7.1 logic but what is the actual surround mode called since denon doesn't have a logic7 surround mode?, 7 channel stereo? You shouldn't use the dsp modes that much in my opinion and should stick with the dolby digital+prologic2x for more accurate sound.

take care,
Brian