Recording Unprocessed Audio From Multiple Microphones iOS

Hi all, I'm working on an app that involves measuring the heading of one iPhone relative to another iPhone. I need to be able to record audio at the same time from at least 2 of built-in data sources at once.

Does anyone know how I can achieve this? I've found that, when using the .measurement mode for an AVAudioSession, the stereo polar pattern is not available. Also, I see that it doesn't seem possible to select multiple data sources.

Is there something I'm missing? If this is not possible, why not?

Recording Unprocessed Audio From Multiple Microphones iOS
 
 
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