I had to make the exact same subwoofer level reduction of 10db on my 3805 to get SACD to sound correct.

However, I haven't gone back yet and checked how DVD-A has been affected. The disk I had sounded fine with the original setting. Unfortunately, my player is out for repair at the moment so I have to wait awhile to check.

I've set my system up with 7.1 as Bridgman mentions and it works really nice. Here's a thread that details the connection if needed.