I'm all for amp headroom. I just disagree at this point with the magnitude that some feel is required. But, as you know from the PM I sent you a half hour ago, I am trying to quantify this better for myself.

Sorry, I don't understand your point about mono. The SPL I calculated above is the theoretical best we can hope for.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated