An earphone has a housing, with a speaker mounted within the housing. A cable inlet contains a cable that includes a wire connected to the speaker. The cable and the cable inlet have different cross-sectional shapes, such that the cable is in contact with the inner surface of the cable inlet over a substantial portion of their length, while a rear volume of the speaker is vented through the cable inlet. This ensures that the cross-sectional area through which the rear volume is vented through the cable inlet remains relatively constant. The earphone may further comprise a microphone, positioned to detect ambient noise approaching the ear of a wearer of the earphone, and the cable may then further include a wire connected to the microphone.