I suggest that not only are the mics potentially picking up movement sounds, but that the earphones are adjusting to changes in air pressure from chewing, resulting in some noises.I have this problem with Airpods Pro, Sony XM4 and most notable, the Devialet Geminis.
With ANC on. and when chewing, I get this driver flex like noise especially in the left ear. Pops, crackle, some static sounding interference (APPs)
For instance the Geminis are unusable with ANC HIGH ON and with silicone tips. I would say the XM4's are in the same category.
Now I have to use Comply Foam (TW-200-C) on both the Sony and Devialet. The Devialets I also have to use ANC LOW.
The APPs just give this static noise, and a kind of distortion when chewing and also when taking a call.
There's no noise at all when ANC is off with either of the TWSs!
With my pinky finger in the left ear, I feel that the jawbones affect the ear canal a lot in the left ear when chewing/opening mouth. (sorry I couldn't explain it better)
I guess this is the reason? The mics are picking up the movements and I get this noise with ANC on??
All that said, not to state what you may already know, but wrt to APP, apple has a repair program for older APP that have noises such as you are describing.
An affected AirPods Pro may exhibit one or more of the following behaviors:
- Crackling or static sounds that increase in loud environments, with exercise or while talking on the phone
- Active Noise Cancellation not working as expected, such as a loss of bass sound, or an increase in background sounds, such as street or airplane noise