So the total SPL number is only the noise limit.
Not an indication of performance or quality.
That changes things.
They do not say the freq changes from 20-20k in the P420 with mic pad on.
THD occurs after a level, but isnt that the SPL?
What would you use to gauge microphone performance then? ..dont say ears..the scribble line their art department comes up with in the back of the manual?
Microphone specifications tend to be about as loose as a cow with amoebic dysentery. Even some big names and high cost mics leave of frequency limits and such data.
SPL limits are especially vague. Often just 'a' limit, 130dB SPL. Better if they specify a distortion figure such as " 0.5%THD at 130dB" (bandwidth? don't be silly!) but often max SPL is quoted for 1% THD so mics are not comparable.
But even 'thd at X SPL' is a bit vague. Where is the source ref mic? Sensitivity is given (or bloody should be!) as dBV at 1 Pascal (Pa) and that is a pressure on the diaphragm, obviously 130dB at 1mtr causes less pressure than at 100mm.
But much of this is academic. Much as I love me specifications (as many here will tell thee!) the basic performance of most microphones is perfectly acceptable.
For capacitors a sensitivity of -40dBV/Pa (10mV) is easily good enough to make the noise of all but the grottiest preamp inaudible. A self noise figure of 20dB is good enough for most applications but very quiet instruments, nylon strung guitars say and speech might demand better.
Overload capacity is really only a problem for a few situations. Drums of course and brass. Some people can sing loud enough to overload the cheaper capacitors but that is rare and good mic technique can mitigate that. Or just use a bloody dynamic!
Paper specs are pretty crap but then of all the things used in the recording chain the microphone is surely THE most subjective? Much BS is written about pre amps and converters but in reality these make bit a tiny difference*.
*Except of course those pres CHOSEN for their 'attitude'.
Dave.