US Patent 8976994 Earphone having an acoustic tuning mechanism

An earphone comprising an earphone housing having a body portion acoustically coupled to a tube portion extending from the body portion, the body portion having an acoustic output opening to output sound from a driver positioned therein into an ear canal of a wearer. An acoustic tuning member is positioned within the body portion for acoustically coupling the driver to the tube portion. The acoustic tuning member defines a back volume chamber of the driver and includes an acoustic output port for outputting sound from the back volume chamber of the driver to the tube portion to improve an acoustic performance of the earphone.