The impotence of comparing frequency plots of mics to shape sounds becomes apparent, latest when you considering pair matching.
I just finished modifying/upgrading a pair of new U87Ai mics for a prominent classical pianist. The mics sounded a bit different in timbre from one another- not much, but enough so, that I was not able to eliminate the deviation and optimise the sound by tweaking low or high end response in the amps. It was clearly the capsule character imprint that made the difference: one was a bit forward in the mids, but slightly attenuated in the highs. The other was silky throughout, with a little bit of a 'blah' factor in the intelligibility range. Not really missing anything there, but just not lively enough for my taste.
Now, explain anyone to me, how what was desirable and what was not in these two mics could be detected by looking at a frequency chart, and what one could do about it to correct the shortcomings of both mics/capsules with the help of the chart? While the phenomena were clearly audible, a frequency chart would not be able to correlate this to what I heard, and offer a path to a solution.
I ended up splitting the better sounding of the two capsules, so that I would have two front sides with similar timbres, then fine tuned capsules and mic amps a bit, to the point that both mics now sound indistinguishable from each other to my ears.
Facit: The outcome, rather than the starting point, would probably be the more telling and interesting exercise to plot a frequency graph of: how close would these plots now be? Or would they still tell different stories, while our ears judge the mics identical in sound?