Apple-Apple Bluetooth speech codec is a variation of AAC, I believe. AAC-LD if I remember correctly. But still, having microphones in one's ears is suboptimal.

Apple-Apple Bluetooth speech codec is a variation of AAC, I believe. AAC-LD if I remember correctly. But still, having microphones in one's ears is suboptimal. There's a lot of processing required even though the codec is no longer completely awful. On an unrelated note, I tried doing calls with a stereo mic setup but participants were actually uncomfortable with the ASMR-like effect of the audio.