My understanding is that, based on some minor details discussed in hands on reviews after the 2013 iMacs came out, is that apple mico-sized the microphone holes on the front and back. They are so small you cannot feel them and you can barely visually perceive them. I believe this having the following benefits:
- Improves uniformity in omnidirectional sensitivity and tonal perception.
- Prevents noise being generated when air moves across the microphone opening
- Keeps dust and moisture out of the case.
Apple did put two microphones in the mac, one in front and one in back to improve noise cancellation for features such as face time.
It never stops amazing me how much tech and features apple puts into their products that they rarely ever tout or put in online specs and promotional language. once apple introduces a feature such as this, they may mention in in some side note somewhere shortly after release, and then they rarely ever mention in publicly again.
My realization of this started many years ago, all they way back when apple designed laptops to sense when they are falling in order to park the hard drive head and protect it. Apple mentioned that feature during that generation of laptops, has continued to include improved versions of this tech in one form another, and then never talked about it again in any future iteration. apple hates competing on long lists of specs except when it comes to ports and interfaces, even then they leave out as much detail as they can get away with.
sorry for the long post.
-J