Hi Zimm,
It's really an amplifier design issue, and an engineer would have to carefully examine the schematics of a particular AV receiver as well as bench testing it under various load conditions to determine why some AV receiver brands like Denon and Sherwood Newcastle seem to have beefier amp sections and less trigger-happy protection circuitry.
At Axiom, our chief R&D electronics engineer, Tom Cumberland, who designed amps for Macintosh, Outlaw, Harman/Kardon, Luxman and others, did indeed do that with the Denons and the Sherwood Newcastles. What we discovered (before taking on the Sherwood line) was that even the least expensive entry-level models of Sherwood and Denon would drive the 4-ohm M80s to very loud levels in our listening room without clipping or going into current limiting. Of course, if you push them past their output limits, they'll get edgy or clip.
Regards,
Alan
