I'm using Audio Queue Framework with sample rate 44100 Hz to record data from the microphone on iPhone.
Then I test frequency response for iPhone 4 and iPhone 4s. iPhone 4s mic is blind on frequencies higher than 20 kHz unlike iPhone 4.
It seems like the microphone is better on previous model. Is it hardware limitation? Is it software limitation? Or some misconfiguration (enabled noise compession or something else)?
No one can hear frequencies that high - for most people, the threshold is somewhere around 15kHz.
So the 4s cuts out unnecessary frequencies - potentially making it better than the iPhone 4.