Update on my -12db Audyssey odyssey.
When using the balanced/XLR connections from the Marantz to my amps-that-have-no-gain-control, my fronts, center, and surrounds were all trimmed by -12db by Audyssey. Which is a no-no. It means Audyssey failed to build its filters properly for those speakers because it hit a hardware limitation on the trim...
Following what was suggested here - first I ordered line attenuators - but they're still a week or two away from delivery. So last night I followed the other suggestion and replaced the XLR connections with good, ol' fashioned RCA connections. (I died a little inside as I performed the replacement. Especially given how old my RCA cables are. They are Monster RCA cables! It's been over a decade since I wasted money buying Monster cables...)
Anyway - when I ran Audyssey this time - I have acceptable trims. Fronts are -7.5/-7.0. Center is -7.0. Surrounds are -9.0/-9.5. All much better than -12.0 db. So - yes - switching over to RCA did the trick for Audyssey with my combination of efficient speakers, speakers close to the main listening position, and sensitive amps.
I dug a little further into the specs and I think I found the root of problem. On the 8801 Audio specs it states:
- Unbalanced pre-output: 1.2 V
- Balanced pre-output: 2.4 V
But for my amplifier, the specs state:
- Single Ended 22K ohms
- Balanced 44K ohms
- 1 Watt Output 120mV
- Full Output 1.68 V
So my amps will run full-out at 1.68V, but the 8801 is feeding them up to 2.4V on the XLR inputs. Scary. Basically this particular Marantz isn't meant to be used with amps as sensitive as mine? Or are line attenuators standard between pre-amps and amps? I was hoping to avoid line attenuators or anything that alters the signal. I really wish the 8801 had a max-voltage setting on its pre-outs.