Not necessarily, a digitally connected mic can easily be calibrated to an absolute level. The same can not be said about any analogue connection.I would have thought an external mic is an external mic however it is connected.
Not at all. Apple provides a far more restricted and thus relatively well-defined ecosystem (not only) when it comes to built-in microphones and associated calibrations. Quite a number of HiFi manufacturers did rely on iPhone measurements only for that very reason. However, the quality of iPhone microphones is not necessarily better and not even necessarily good. The general trend in the industry is toward higher quality external microphones with matching calibration files.Doesn't it seem strange that all the testing for room correction is only taking place on iPhones?
There's not really any difference between iOS and Android. The difference is just how many deviations there are between implementations.Will there ever be any testing on Android?
Once we can use a certain (external) mic (preferably through USB) with an associated calibration file, the OS really doesn't matter at all.