US Patent 11575985 Mass loaded earbud with vent chamber

Intra-concha earphones are disclosed. In an embodiment, an intra-concha earphone includes a housing having a rear space divided into a back volume, a bass duct, and a vent chamber between a driver and a rear wall. The vent chamber may be acoustically coupled with the back volume through both an acoustic port and the bass duct. Furthermore, the vent chamber may be acoustically coupled with a surrounding environment through a vent port, which may be a sole acoustic opening in the rear wall. Thus, sound emitted by the driver may propagate through the acoustic port and the bass duct to meet in the vent chamber before being discharged through the vent port to the surrounding environment. Other embodiments are also described and claimed.