Most people using the term car audio to describe the sound system in an automobile, though the term also refers more broadly to the field of mobile entertainment and is becoming a sport at large. A stock car audio system refers to exactly what was specified by the manufacturer when the car was built. A custom car audio installation could mean anything from the upgrade of the radio to a full-blown customization of a car based around delivering exceptional sound quality or volume from audio equipment.

The most common and familiar piece of audio equipment is the radio/tape player/CD player which is generically described as a headunit. It is also the most likely component to be upgraded with an after market item. A recent development in head unit technology has been the addition of CD players with MP3 support.

Many cars include at least a CD player some have the option for a CD Changer which holds multiple disks either in the head unit itself or in a separate unit usually located in a trunk or console.

Speakers are generally located in doors and rear parcel shelves of sedan in modern cars. Before stereo radio was introduced, the most common speaker location was in the middle of the dashboard pointing through perforations towards the front windshield.

High_end audio systems include Component Speakers that consist of a matched tweeter, midrange and woofer set. These component pairs are available in two speaker and three speaker combinations, and include a cross-over which limits the frequency range that each component speaker must handle. In addition a subwoofer(s) is provided for low frequency music information.

Amplifiers provide the necessary music power, measured in watts to drive the speakers. High Power amplifiers require large gauge cable to provide adequate voltage and current to the amplifier.

Alternators may be upgraded from the stock unit to increase the current capability of the vehicle's electrical system, often required of high-power audio system components.

Other components that make up high end car audio installations may include:

• amplifiers
• audio processors
• cables
• crossovers
• equalizers
• mobile video (VCRs, television, DVD and navigation)
• stiffening capacitors

Common modifications in high end car audio installations:

• amp racks
• speaker pods
• subwoofer enclosures

History

The movement to add more than just a basic radio to a car largely originated on the west coast of the United States in the late 1970s. Several early manufacturers and enthusiasts began building audio amplifiers to run on twelve volts (the standard voltage in automotive electrical systems). Jim Fosgate, later to become the founder of Rockford Fosgate was one such pioneer. The company a/d/s also brought an amplifier to market in 1978.

At first, speakers from the home audio and professional markets were simply installed into vehicles, however, they were not well suited to the extremes of temperature and vibration which are a normal part of the environment of an automobile. Modified drivers were developed to cope with these factors.

Subwoofers were introduced in ___. Believing that "louder is better", there were some extremes of installation of multiple over-sized speakers. In 1985, Wayne Harris' famously modified a 1960 Cadillac Hearse to feature several 24 inch diameter subwoofers.

Today, advances in acoustic technology mean that even two 10s (inches) in a well designed efficient enclosure can produce more than 130 decibels SPL (sound pressure level) within the cabin.

Car audio competitions started in the early 1980s in a quest to find the loudest and/or most outrageous installations. Early on, little credence was given to sound quality. In the early 1990s, several organizations, including IASCA, began car audio competitions focusing on sound quality. The two styles - SPL vs. sound quality - have become almost mutually exclusive.

Notable car audio installers

• Speakerworks, Orange county, California.

Steve's Electronics Online (http://www.steveselectronics.biz)

See Also

• DB drag racing

Notable Installations

• The SpeakerWorks/USD Audio Buick (http://www.usdaudio.com/sw/cars/buick/)
• Wayne Harris' Hearse (http://www.termpro.com/showcars/terminator/terminator.html)
• Steve Brown's M3 (http://www.caraudiomag.com/v_features/0107_cae_overtop/)
• Scott Buwalda's Altima (http://www.altimas.net/forum/showthread.php?s=0e426414380983c8e6f051b0cbbe603e&threadid=140304)
• Steve Cornell's Impala SS (http://www.rtol.net/scornell/index.html)
• Earl Zausmer's BMW (http://www.milbert.com/earl/)
• Gary Bigg's Buick Regal (http://www.jbl.com/car/featured/installs/buick.asp)
• Mark Eldridge's 4Runner (http://www.jbl.com/car/featured/installs/4-runner.asp)

Notable Manufacturers and Brands

• a/d/s [1] (http://www.adst.com/)
• Alpine [2] (http://www.alpine.com)
• Clarion [3] (http://www.clarion.com)
• JBL [4] (http://www.jbl.com/car/default.asp)
• JL Audio [5] (http://www.jlaudio.com)
• Kenwood [6] (http://www.kenwoodusa.com)
• Pioneer [7] (http://www.pioneer-eur.com)[8] (http://www.pioneerelectronics.com)
• Power Acoustik [9] (http://www.poweracoustik.com)
• Precision Power [10] (http://www.precisionpower.net)
• Sony
• Soundstream [11] (http://www.soundstream.com)
• Rockford Fosgate [12] (http://www.rockfordfosgate.com)
• Focal [13] (http://www.focal-jmlab.fr/gb/car/index.htm)
• DLS [14] (http://www.dls.se/english/index.htm)
• Milbert Amplifiers [15] (http://www.milbert.com)