I don't think you will have a problem with low listening volumes, but one thing does concern me. As far as I can tell the 3803 isn't rated for 4ohm speakers. In the manual it lists 210w/ch at 4ohms. But in the output terminal specs it lists 6-16ohms for the speakers. They list the THD going from 0.05% at 8ohms to 0.7% at 6ohms, and don't list 4ohms at all, so who know how bad it would be. (The 4802 has the better 0.05% at 6ohms)
I see other people are using a 3803 with M80s so I guess it works, but it doesn't look like it was ment for it. I looked and not even the 4802 or 5803 list 4ohm output in their specs. (Though like the 3803 it is listed in the dynamic power category)
I looked at Onkyo's site, and found that even their top of the line TX-DS989II can only handle >=6ohm speakers. But, their newer TX-SR800, and TX-NR900 have 4ohm support, and even list 3ohm specs in the dynamic power category.
Michael
