Patent ID: 9288569
Filing Date: 2016-03-15
CPC Classification: H04R

Claim Text:
1. An earphone adapted to provide an acoustic output signal to an ear of a wearer in dependence on an earphone audio signal and further adapted to be arranged on the wearer's head in an operating position such that a front cavity between the head and the earphone is separated from ambient space, the earphone comprising: a housing having a wall separating a rear cavity having an acoustic compliance from the front cavity and from ambient space; an ear cushion arranged and adapted to attenuate acoustic signals entering the front cavity from ambient space when the earphone is in the operating position; a first diaphragm reciprocatably suspended across a first through hole in the housing wall between the front cavity and the rear cavity and adapted to be actively driven to provide at least a portion of the acoustic output signal; and a second diaphragm reciprocatably suspended across a second through hole in the housing wall between the rear cavity and ambient space such that the second diaphragm and the rear cavity constitute an acoustic resonant system with an acoustic resonance at a resonance frequency, characterized in that: and wherein the acoustic resonant system is configured such that said resonance frequency is below 500 Hz; wherein the second diaphragm is adapted to attenuate acoustic signals entering the rear cavity from ambient space at frequencies above said resonance frequency.