Fuck if I know, all I know is you can sit next to a blender in a busy office full of crying babies and barking dogs while writing a dissertation on an electric typewriter and the person on the other end of the line would never be able to tell. Professional headsets (like in the $300-$500 range) are honestly pretty incredible. If these silicon valley offices are too noisy for a high end EOS to handle, or if they genuinely have that many people constantly talking all day to the point that it's a problem then they need to go back to the drawing board. Steno masks have their place but for anything a garden variety techbro is doing they're either performative bullshit or a lazy bandaid. I guaranfuckingtee bossman has no interest in putting one of these on.

I imagine it's like the Active Noise Canceling (ANC) mode of headphones which will monitor background noise and then calculate the inverse sound wave and play that sound to you which in effect mostly cancels out the background noise (works better for certain frequencies than others). For a microphone they could do the same but instead of playing you the inverse sound, they could play it through the microphone for whomever is listening.