My system score was a 6. 4500 Sq. foot room (with openings), 87DB rated Salons.
I listened a 2-channel CD rips were somewhat compressed. Dynamic Range (DR) of around 8.
I turned it up so a Radio Shack meter measured peaks of 92 DB (fast mode).
After about 1/2 hour the heat sinks on the A51 measured 135 F.
This is louder than I would normally listen to music, but I want a system that can handle occasional excesses
Conventional wisdom is that with these measurements, I should be using under 100 watts.
That cannot be the case, for the heat produced. The A51 has more heat-sink area that most class a/b receivers cannot tolerate this thermal load.
They would either go into protection or current limit and compress the sound.
Watching TV/Movies, the amp is only warm not stressed at all.
IMO, The AH external amplification table is pretty good.
- Rich