Apple recently filed a patent for for a pair of headphones that can auto adjust its volume and noise cancellation. Ear size is not constant for every human, and so noise affects the sound that user gets from the earphone. And Apple came up with a idea that gives the intelligence to the earphone to cancel the noise automatically according to how it fits into one’s ear.
Also detailed in the patent application is a system that would alert users through a push-notification if the headphones have a poor seal.