A head unit, sometimes referred to as a "deck", is a component of a stereo system either in a vehicle or home cinema system which provides a unified hardware interface for the various components of an electronic media system. An antiquated name for a head unit is a receiver; this article focuses on vehicular applications.
The head unit is the centerpiece of the car's sound system. Typically located in the center of the dashboard, modern head units are densely integrated electronic packages housed in detachable face plates. As high-end head units are common targets for theft, many head units are typically integrated into the vehicle's alarm system.
Head units give the user control over the vehicle's entertainment media: AM/FM radio, satellite radio, CDs, cassette tapes (although these are now uncommon), MP3, GPS navigation, Bluetooth, etc. Many audio-only head units afford the user precise control over detailed audio functions such as volume, band, frequency, speaker balance, speaker fade, bass, treble, EQ and so on.
Several OEMs such as General Motors are integrating more advanced systems into vehicle's head units such that they can control vehicular functions such as door chimes and even offer vehicle data such as trouble warnings and odometer information; such a head unit thus serves as a secondary instrument panel.
In as much as head units are a central part of a car's decor, they vary as widely in aesthetics as they do in functionality; in this regard they are analogous to skins.
- MPT 1362 UK code of practice for the installation of mobile radio and ancillary equipment in land based vehicles. Federation of Communications Services Industry, November 2005.
- "How important is your car stereo to you". Head unit. Car stereo reviews. Retrieved 2012-01-03.