Apple has filed for a patent (number 20190058952) for “spatial headphone transparency” that shows the company is looking for ways to make the audio even better on its AirPods and Beats headphones.
In the patent filing, the tech giant notes that a typical consumer electronics headset contains a pair of left and right headphones and at least one microphone that are connected either wirelessly or via a cable to receive a playback signal from an electronic audio source, such as a smartphone. The physical features of the headphone are often designed to passively attenuate the ambient or outside sounds that would otherwise be clearly heard by the user or wearer of the headset.
Some headphones attenuate the ambient sound significantly, by for example being "closed" against the wearer's head or outer ear, or by being acoustically sealed against the wearer's ear canal; others attenuate only mildly, such as loose fitting in-ear headphones (earbuds.)
Apple says an electronic, acoustic transparency function may be desirable in some usage scenarios, to reproduce the ambient sound environment through the earpiece speaker drivers of the headphones. This function enables the wearer of the headset to also hear the ambient sound environment more clearly, and preferably in a manner that is as "transparent" as possible, e.g., as if the headset was not being worn.
Of course, Apple files for — and is granted — lots of patents by the U.S. Patent & Trademark Office. Many are for inventions that never see the light of day. However, you never can tell which ones will materialize in a real product.