I came across a Nokia sound recorder app on XDA that has been tweaked to work with surround sound recordings.
I'm also not sure about the surround processing but it's stable on my Nokia 8, not just for voice, also for noise and music (in high quality AAC mode).The 30 second sample from a late night blues jam was recorded with the screen down sitting at the bar to the right of the stage. The stereo phase wobbles somewhat but it's not bad for a bootleg recording:https://drive.google.com/open?id=1JuzowjzxazdbpjqoIRfspd05yHwg4PSa-- Hans
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