US Patent 9781506 Earphone having a controlled acoustic leak port

An earphone comprising an earphone housing having a wall comprising (1) a front side that joins (2) an end portion in which a primary sound output opening is formed, which joins (3) a face portion in which a secondary output opening is formed, which joins (4) a back side which joins the front side and encloses a driver, wherein the face portion and the front side form a tapered portion of the earphone housing that is dimensioned to be inserted into, and contact, an ear of a wearer, wherein the primary output opening is dimensioned to output sound generated by a diaphragm of the driver contained within the earphone housing into the ear, the secondary output opening is dimensioned to vent the ear to a surrounding environment, and wherein the primary output opening and the secondary output opening face different directions and are positioned over a sound output face of the driver.