Page 41 of your C1 manual has this to say about the multichannel inputs.
"
...this is a straight pass-through of the analog signal from input to output, with no signal modifications
beyond the analog level controls (including volume adjustment and the center, surround, and
subwoofer-level trims on page 3 of the Master remote’s C1/C2 menu)."
This would indicate that there is no bass management provided by the C1 on the multichannel inputs. If you're going to listen to DVD-As, be sure to go through the speaker setup in the Oppo.
Really nice controller, by the way.
