On February 3, 2018 at 16:32, james_aa said...
Thanks, Ernie & Buzz
To pose the the starting point of what made me ask this question another way : how can you make sure that a speaker and amp pairing is correct and wont damage either ?
By making sure the input level to the amplifier is enough to allow it to provide sufficient undistorted power to achieve the desired SPL and by making sure the signal to the speakers isnít more than they can handle, for whatever time is needed.
You need to determine the SPL needed, coverage and duration before anything else, based on the program material (live or recorded music, speech, etc). The speaker sensitivity & efficiency, distance from speakers to the listeners, size of the room and other factors will determine amplifier power.