HEADPHONE

An audio unit (112) carried by a support structure (106) of a headphone (100) that is adapted to sit on a head of a user, the audio unit being held off an ear of the user, comprising: a first acoustic driver (110) carried by the support structure such that the first acoustic driver is located off of the ear, and having front and rear sides; wherein the first acoustic driver is enclosed by a housing (111) defining: a front chamber (114) and a rear chamber acoustically coupled to the front side and the rear side of the first acoustic driver, respectively; wherein the housing comprises a first port (115) and a second port (117) acoustically coupled to the front chamber and to the rear chamber, respectively, the first port being arranged to direct sound toward the ear, the second port being farther from the ear than is the first port and radiating 180 degrees out of phase with the sound from the first port so as to cause far field sound cancellation.