Axiom Home Page Forums General Discussion Technical Questions Tube Amp Drive

Thanks jakeman, but now my confusion.
My 25W amp can give me ~ 14 dB. If the M60's or M80's require 10W min, then I have ~12 dB [ 10*log(25-10) ] to play with.
The M80's have an input impedance = 4 ohms, and an spl=95 dB/W/m., and I should be able to hit 107 dB (95 + 12).
The M60's have an input impedance = 8 ohms, and an spl=93 dB/W/m., and I should be able to hit 105 dB (93 + 12).
And both require 10W min. to be driven.
This tells me that for a given I/P power, regardless of the input impedance, the MT80's are easier to drive than the MT60's.
Where did I error?
Thanks