The composition of a car stereo system is based on four basic components. These are amplifiers, speakers, head units and input devices like graphic equalizer, CD changer etc.

The head unit, as the name suggests, is the core of any stereo system. The head unit or radio is called the central processing equipment of the device. It controls all the functions of the application like turning the volume up and down, adding more bass etc. Every manual sound adjustment is made by the driver through this head unit or radio. Behind the dash of the head unit, there are dozens of wires connected to power, speakers, antennae, and so on.

In addition to volume and bass control, this head unit may have other features as well like fade, 3D sound, bass boost, etc. Unlike the home stereo system, where one can avail a huge space, car stereo systems are required to operate efficiently in the small space of the interior of a car. Thus, when installing a new system, one must take full consideration of availability of space, heat, cosmetic design, power requirements and aesthetics.