dllewel,

You are correct, sir. Running two M3s in parallel from the same amplifier will result in a 3-dB increase in loudness, a change that is sujectively termed "somewhat louder". Six dB is definitely wrong for two conventional speakers run in parallel.

I don't know about the 6-dB thing with the subwoofers, unless it's room gain from corner locations. Will look into it.

Regards,

Alan Lofft,
Axiom Resident Expert (Retired)