After a little more time with the 990 (an entire day so far!), Dolby & DTS (surround) modes are quieter than non-surround modes... The speaker volume level calibration helped a little. But I can play movies at -11 db no problem, where as in five channel/stereo modes, -11 db is VERY loud. I think I know why this is, assuming mine is not defective. I noticed that Channel calibration, I can set individual speakers up to as much as +15 db. It’s helpful to have that flexibility - something my Adcom didn't; it could only attenuate Ctr/LR/RR channels, not boost.

Because there is this +db headroom built into surround modes, +15 is actually 0 db (in non-surround mode equivalent). That would be about the difference I experience between surround and non-surround mode volumes. This is my theory anyway.

After using the auto mic, I see the individual speaker’s volumes are nearly all zero, +2 / -1 at the most. What I’ll probably end up doing is add 10 db to each & all of the individual speaker’s level settings. They will all maintain their proportion with each other, but surround modes will more closely match non-surround volume levels… so if I switch sources, the disparity in volume won’t be as great.

Thank you responders! Is this forum moderated by Outlaw to “approve” my intention (above) with the 990? I don’t want to make a trouble ticket for this type of question. I did make an official trouble ticket two days ago before hooking up anything… to ask if I could use a three pronged non-OEM power cord… They replied quick and said ok if gauge appropriate.