US Patent 10356510 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 primary output opening is dimensioned to output sound generated by a diaphragm of the driver contained within the earphone housing into the ear and 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.