User Configuration > Administrative Templates > Microsoft OneNote 2016 > OneNote Options > Audio and Video
User
HKCU\software\policies\microsoft\office\16.0\onenote\options\audio
Specifies whether 1 or 2 channels are used when recording audio. If the appropriate codec is found, then this is the default number of channels used in the Format setting for Linked Audio found under File tab | Options | Audio & Video.