Patent attributes
An active noise-reduction headphone arrangement has a housing bearing a loudspeaker having a first diaphragm surface coupled to a first volume of air bounded by and coupled to a user's ear, and a second diaphragm surface bounding a cavity within the housing assembly so as to define a second volume of air, rearward of the diaphragm; a conduit provided in the housing, the conduit being in fluid communication the ambient air via a first acoustic couple means having a first characteristic acoustic impedance, the conduit also being in fluid communication with said second volume of air via a second acoustic couple means having a second characteristic acoustic impedance; and a microphone having an inlet coupled acoustically to a predetermined location within the conduit.
