Abstract: A speaker unit including a housing, a connector adapted to form a physical connection with a cooperating connector of a second speaker unit in order to physically join the speaker unit to the second speaker unit, and an input port adapted to form an electrical connection to an input source. The speaker unit may further include an electrical coupling that is automatically engaged with an electrical coupling of a second speaker unit when the connectors are fully engaged. A speaker unit may include a cover for providing and/or adjusting an opening at the back of a speaker unit.