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1. Don Romano (alt) (thor@noagendasocial.com)'s status on Saturday, 13-Apr-2019 14:46:00 EDT Don Romano (alt)

   Knowles SPH0641 MEMS digital microphone. That's a very good frequency response for the human hearing range. You could use this as a calibration microphone. I reckon the bump at 25 kHz is the resonance frequency of the diaphragm. That's probably a compromise. Too high, and the diaphragm would be too stiff, too low and it would be audible. It's also a decent compromise for the ultrasound range, since it leaves the 36 - 70 kHz range flat to within +/- 1 dB.

   1. Don Romano (alt) (thor@noagendasocial.com)'s status on Saturday, 13-Apr-2019 15:05:33 EDT Don Romano (alt)

      in reply to

      That peak at 25 kHz kind of explains why smartphone and tablet microphones sound so crisp compared to more traditional microphones. It doesn't look too hard to neutralise the response with some digital EQ filters. It wouldn't surprise me if some mobile devices already do that, since digital filters are basically free.