Future AirPods Max units may have pressure relief valves as hinted by a newly granted Apple patent for, well, a “Pressure Relief Valve for Headphones.”
About the patent
The patent involves a pressure relief valve for relieving pressure experienced by a user wearing closed-back headphones. As Apple notes in the patent, headphones typically include a pair of earcups which encircle the user’s ears and are held together by a headband.
Headphones can be classified into two general categories based on the design of the earcups, namely closed-back or open-back earcups. Closed-back earcups surround the user’s ears and have a sealed (i.e., closed) back. Open-back earcups also surround the user’s ears but have a back which is open to the ambient environment surrounding the earcup.
Both the closed-back and the open-back designs have their own acoustic advantages and disadvantages. For example, closed-back earcups may have good sound isolation since they are sealed off from ambient noise. In addition, the size and clamp force of the earcups may also be modified to further increase sound isolation. Features of the closed-back design, such as the sealed back, size and clamp force of the earcups allow this design to mechanically or passively attenuate ambient noise.
However, Apple notes that, due to the closed design of closed-back earcups, pressure changes within the portion of the earcup surrounding the user’s ear may be uncomfortable. The tech giant wants to make the AirPods Max more comfortable to wear for long periods.
Summary of the patent
Here’s Apple’s abstract of the patent: “A headphone comprising: two headphone earcups each comprising: an earcup housing defining an active chamber that acoustically couples a sound output side of a speaker to an ear of a user, and an inactive chamber that surrounds the active chamber; and a passive valve assembly configured to open in response to a positive pressure and a negative pressure within the active chamber to fluidly couple the active chamber to the inactive chamber and equalize a pressure between the active chamber and the inactive chamber.”
