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Car Radio (audio systems)

Car audio, also known as ICE (In Car Entertainment) is a term used to describe the sound system fitted in an automobile. A stock car audio system refers to one that was specified by the manufacturer when the car was built. A custom car audio installation can involve anything from the upgrade of the radio to a full-blown customization of a car based around its audio equipment. Events are held where entrants compete for the loudest or most innovative systems.


The most common and familiar piece of audio equipment is the radio/tape player/CD player/DVD Player which is generically described as a Head unit, which also can be called a deck, after older tape decks. 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, WMA, AAC, and USB, Bluetooth and Wi-Fi 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.

Our horizons have been broadened even further-even newer technology is the addition of DVD players and LCD screens. The position of the LCD screen differs for different DVD players - certain DVD players require the screen to be mounted on the roof of the car (just above the front windscreen), while others require the screen to be attached to the back of the headrests of the front seats and some DVD players have the screens come out of the head unit.

Some equipments includes automotive navigation system (see center console).


Speakers are generally located in doors and rear parcel shelves of a sedan in modern cars. High-end or competition stereo systems often have speakers mounted in "kick panel" enclosures, allowing for larger drivers and better driver placement. 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 (small, high frequency), midrange (medium, medium frequency) and woofer (large, low frequency) set. These component pairs are available in two speaker and three speaker combinations, and include an audio crossover which limits the frequency range that each component speaker must handle. This allows each cone to produce its optimal frequency for maximum sound quality and volume. In addition subwoofer(s) are provided for bass and sub bass(ultra low frequency), which is felt, rather than heard. Crossover systems can be active or passive crossover networks. Active electronic crossovers divide the signals before they are sent to the amplifiers giving a dedicated amplifier channel to each individual driver in the component system. Passive crossover networks divide the signal after amplification, making it possible to run multiple speaker component sets using just one channel.

5.1 and even 7.1 channel surround sound systems are now being integrated in to some cars by both aftermarket enthusiasts and car manufacturers themselves. These systems include the full compliment of front left, right and center speakers along with rear right and left surround speakers (7.1 systems include left and right side surround speakers) along with digital surround sound processors. They can allow you turn turn your car in to a virtual rolling theater. This is becoming increasingly popular with the advent of SACD and DVD Audio which contain music encoded in 5.1.


Amplifiers provide the necessary music power, measured in watts to drive the speakers. High Power amplifiers require a large gauge cable to provide adequate voltage and current to the amplifier. The amplifier is a very important component of a loud speaker system. Don't connect too many speakers to the head unit alone. Make sure that the total power handling capacity of the speakers connected to the amplifier or head unit is greater than or equal to the power of the amplifier or head unit.

Sound deadening is often used in the door cavities and boot/trunk area to provide less rattling of the metal in the car, especially the boot/trunk, and to help produce a cleaner sound by absorbing instead of reflecting sound waves. It is a rubber or asphalt-like substance that can be sprayed on or glued on in sheets.


Upgrading the vehicle's current capability

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. An additional Deep Cycle battery (or, for very large systems, banks of batteries) can be deployed (often charged via a Split charge relay) to limit voltage drop and allow the system to be played for long periods without the vehicle's engine being run. Installing a capacitor is another option when trying to provide substantial power to the audio system.

a powerful after-market audio system installation in a Toyota.
a powerful after-market audio system installation in a Toyota.


From the earliest days of radio, enthusiasts had adapted domestic equipment to use in their cars but the commercial introduction of the fitted car radio came in the 1930s from the Galvin Manufacturing Corporation. Galvin Manufacturing was owned and operated by Paul V. Galvin and his brother Joseph E. Galvin. The Galvin brothers purchased a battery eliminator business in 1928 and the corporation first product was a battery eliminator that allowed battery-powered radios to run on standard household electric current. In 1930, the Galvin Corporation introduced the first commercial car radio, the Motorola model 5T71, which sold for between $110 and $130 and could be installed in most popular automobiles. The name Motorola was created by Paul Galvin combining the term “motor” for motion for sound [1].

In Germany Blaupunkt fitted their first radio to a Studebaker in 1932 and in the United Kingdom Crossley offered a factory fitted wireless in their 10 hp models from 1933.

The early Car Radio receivers used the battery voltage (6.3 Volts at the time) to run the filaments, and generated the required High Voltage using a Vibrator to drive a step up transformer. The receivers required more stages than the typical home receiver in order to ensure that enough gain was available to allow the AGC to mask signal fading as the car was driven around.

When Cars switched to 12 Volt bateries, the same arrangement was used, with tubes with 12 Volt heaters.

In 1952 Blaupunkt became the first maker to offer FM receivers.

The introduction of semiconductors allowed the output stange to change to a transistor, which soon lead to the elimination of the Vibrator, and the use of "Space Charge" tubes that only required 12 volts on their plates.

Advances in electronics allowed additions to the basic radio and Motorola offered 45 rpm disc players fitted to some Chryslers from as early as 1956. Tape players using reel to reel equipment followed but their bulk ensured popularity was limited but this changed in 1964 when Philips launched the Compact Cassette. Other early manufacturers and enthusiasts began building extra audio amplifiers to run on 12 volts (the standard voltage in automotive electrical systems). Jim Fosgate, later to become the founder of Rockford Fosgate, was one such pioneer. The company 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.

Today, advances in acoustic technology mean that even two 10-inch speakers in a well-designed efficient enclosure can produce more than 100 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. For example, in 1985, Wayne Harris famously modified a 1960 Cadillac Hearse to feature several 32-inch subwoofers. Little consideration was given to sound quality early on, but 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. The loudness competitions have become known as DB drag racing.



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