'Car audio' is a general term describing the sound system fitted inside an automobile. Similarly, the term 'stock car audio system' refers to the sound system specified by the manufacturer when the car was built. A custom car audio installation, on the other hand, can involve anything from upgrading of the radio head-unit to a full-scale modification of the car based around its audio equipment - such as subwoofers, stereo CD changers, etc..

The audio equipment commonly used is the radio, tape player, CD player, DVD Player. These are generically described as a Head unit. The addition of CD players with MP3, WMA, AAC, and USB, Bluetooth and Wi-Fi support are new developments in head unit technology.

Today most of the cars come with at least a CD player / CD recorder, and some come with option for a car stereo CD changers able to hold multiple disks in the head unit itself or in a separate unit located in a trunk or console. Today main type of CD changers can be categorised into External Cartridge, Internal Cartridge and Carousel CD changers.

Stereophonic sound, commonly called stereo, is the reproduction of sound using two or more independent audio channels in way to create a natural impression of sound heard from various directions, similar to that in natural hearing. In popular usage, car audio stereos usually mean 2-channel sound recording and sound reproduction using data for more than one speaker simultaneously.

During the mono radio era, the speaker was usually located in the middle of the dashboard. But with the arrival of the new technology in sound system that is the car audio speakers, they are now put in doors and rear parcel shelves in modern cars. Another kind of this stereo system is the stereo CD changers which is good for large drivers.

To drive the speakers you have that have an amplifier. This gives power to the music you are listening. A good car audio speaker system must have an amplifier, which is its very important component. Be sure that the total handling capacity of the speaker which is connected to the amplifier is greater than the power amplifier.

Car audio is a sound system fitted in a car. The car manufacturer fits the basic system whereas the owner can fit and customized system of minor/major changes including car stereo CD changers installation. Head units refer to radio/tape/CD/DVD Player and with recent developments CD players are provided with WMA/MP3/AAC/USB/Bluetooth/Wi-Fi. CD Changer holds multiple CDs and facilitates continuous viewing. They can be External/Internal Cartridge or Carousel type. Car audio stereos use two channels to reproduce sounds with directional effect. The car audio speakers are positioned in doors/rear parcel shelves. A good car audio speaker system must have an amplifier and the speaker's capacity should be higher than amplifier.