A new patent granted Tuesday reveals that Apple is exploring a new headphone technology that uses bone conduction technology to measure skull vibrations. This information, combined with a series of microphones along the headphone wire, would be used to filter external noise and improve voice clarity when making a call in a noisy setting.

The USPTO patent, titled “System and method of mixing accelerometer and microphone signals to improve voice quality in a mobile device,” describes a set of headphones that will distinguish between ambient noises and the user’s voice. The headphones contain accelerometers that can sense the wearer’s bones vibrating as they speak.

Bone conduction headphones are nothing new, but normally the conduction is used to send audio rather than receive it – unlike Apple’s patent that only uses it for sending. Current bone conduction headphones wrap over the ears, pressing against the cheekbones and vibrating them when music is played, rather than placing miniature speakers in the user’s ear, like traditional headphones. One company that manufactures such headphones is Aftershokz, who use the technology to keep the ears open and allow the wearer to listen for any ambient noises.

Bone conduction isn’t the only new addition in Apple’s patent. Unlike Apple’s current EarPods headphones, which contain a single mic built into the cable, these new earphones have several microphones, at varying distances away from the wearer’s mouth. All this information is put together to separate the surrounding noise from the voice, so when a user places a call, the actual voice comes through crystal clear.

Apple also received a patent on Tuesday for a liquid-resistant speaker port. The patent, titled “Liquid resistant acoustic device,” describes an iPhone speaker that protects against water flooding the insides through a variety of methods. One of these methods is by using a “mesh umbrella,” and pushing water away when it makes contact. Like the bone conducting headphones, these are only at the patent stage, so it is not clear how long we will have to wait before they hit shelves, if they ever do.