The inbuilt microphones do work very well. The whole loop is, as you say, heavily adjusted to compensate for the resonances of the unit. I wouldn't be surprised

The inbuilt microphones do work very well. The whole loop is, as you say, heavily adjusted to compensate for the resonances of the unit. I wouldn't be surprised if there was some quite fancy DSP powering that. I thought that was for making facetime and skype etc work well though? Musicians are not using the built-in audio interface, regardless of quality considerations, it lacks the necessary functionality.