According to the patent, it describes a pair of headphones that comes with microphones placed around the earcups. These microphones will be used to try and determine if the headphones are worn correctly, and this is done by measuring the volume of the user’s voice. As to why such a system is necessary, it has been speculated that perhaps this could be a sign of Apple working on a pair of reversible headphones.
Basically instead of users trying to figure out which earcup is for which ear, this system would allow the wearer to put on their headphones in any orientation and it will adjust itself accordingly. We have been hearing rumors that Apple could be working on a pair of high-end headphones.
They have yet to be officially launched, but the rumors are claiming features such as noise-cancellation and wireless pairing functionality similar to that of the AirPods. That being said, this is just a patent which means there’s no telling if and when Apple will actually make it a reality.