I think OP is talking about the compression and bit rate, not the placement of the mic.
When the mic is turned on, many headsets go from sounding good enough to sounding absolutely horrible. Something about switching from A2DP to HFP, and sharing the bandwidth between the incoming audio and outgoing audio.
AirPods are impacted much, much less, largely I think because the AAC-ELD codec is decent, and Apple OSes switch the audio from stereo to mono when the mic is on (which seems like a no-brainer IMO, but I guess not all operating systems do this).
When the mic is turned on, many headsets go from sounding good enough to sounding absolutely horrible. Something about switching from A2DP to HFP, and sharing the bandwidth between the incoming audio and outgoing audio.
AirPods are impacted much, much less, largely I think because the AAC-ELD codec is decent, and Apple OSes switch the audio from stereo to mono when the mic is on (which seems like a no-brainer IMO, but I guess not all operating systems do this).