i've never measured the M80s alone, but these are a few results
i got when playing some movies at Reference Level.
the SPL meter was always set to "peak" and "fast", without filtering (flat response curve in the low frequencies), and the meter sitting at the usual listening distance on an armrest.
300: 118.8 dB
The Pacific: 118.7 dB
Bourne II: 117.0 dB
Bourne III: 118.2 dB
Super 8: 122.3 dB (Train crash, a heart stopper)
Super 8: 119.7 (bus turnover, mainly low frequencies here)
WOTW: 122.4 dB
the highest power output measured was the train crash;
i measured gross Watts used by the M80s amp, which came out to approximately 445 W/ch net going to the speakers after compensating for the amp's efficiency. this is an approximation only, as the Watt meter is not very precise.
under those conditions, the sound is always devoid of audible distortion, which was my principal goal when i bought the audio equipment a few years ago.
Edited by J. B. (06/28/13 07:12 AM)