The head unit links and controls every system component used. It pays to buy a head unit capable of more than you initially require, this will eliminate the need to upgrade later on.
If your budget is tight, a basic head unit that receives radio and plays tapes is the route to take. But ensure it can be linked to a CD multi-changer. A midrange unit packing RDS radio, single CD and remote control is a better option. Saving up for a cutting edge unit would be the ultimate. These have features such as Mini-Disc drives, TV screens and multi-CD drives. Buying a head unit with built-in flip-out screen will save hassle when you fit a video or games console. Top features, on any unit, include removable faceplates, RDS (which re-tunes to the strongest signal and traffic information) and in-built equalizers for instant sound adjustment.
A CD changer (or multi-changer) stores a number of CD's in a magazine which are accessed by you head unit.
Ensure the changer you by will work alongside your present head unit - as many companies use dedicated connectors.
Ensure the changer is mounted as specified in the instructions or tracks will skip, or stop altogether, when you hit a bump or the road surface deteriorates.
DVD is the latest in video technology - a CD capable of recording and playing masses of digital information, be it music or films.
The only downside is that with any cutting edge technology, DVD is expensive - especially those designed for in-car use.
Cables connect all the components in an ICE install transferring either power or signals.
RCA leads can make a big difference to the sound your system puts out. Their resistance, capacitance and inductance affect response and quality of signal.
Speaker leads and power cables come in a wide variety of types and colors, and vary massively in price.
Like any other speakers, tweeters produce sound by vibrating at various frequencies. However, they have tiny cones that handle the high frequency notes normal speakers struggle to produce.
High frequency notes don't travel well, so tweeters are designed for installation in line with the listener's ears. To help you achieve this some come with ball-and-socket mounting for easy set-up.
Midrange speakers produce all sound that is not pure treble or bass. They can make or break a system, so avoid fitting cheap midrange speakers to a quality head unit.
Cheap midrange speakers are prone to blowing when driven at high volumes for long periods. If you run your system hard, you must fit good quality midrange speakers. Top quality midrange speakers use cast-alloy baskets, composite cones, twin voice coils and gold connector terminals - all of which improve sound quality and performance.
6x9's use a six-inch by nine-inch midrange cone, with a centralized tweeter on top.
They are designed to ensure that back seat passengers get the full, rounded sound - not just heavy bass. They can be installed up front and give a good sound. However, a large door-build would be required and a combination of midrange and tweeters would be far more flexible.
Subs utilize massive magnets, huge cones and sizeable voice-coils to move the cone by the amount required to produce shaking bass tones.
The two styles of subs available are free-air and enclosed. Free-air subs use your car's boot as its pressure box. Enclosed subs require a sealed and ported box of set dimensions - these are more flexible and set friendly.
Sizes range from small eight-inch cone units (ideal for rapid punchy bass), to a massive fifteen-inch cones for deep, long bass tones.
As their name suggests, these amplify the signals sent from your head unit to the speakers.
Amps are packed with components that boost sound output. Transformers distribute and regulate power flow. Power storage capacitors ensure the amps power level is not sucked dry by heavy bass lines. Passive crossovers break down the output signal into bass, midrange and treble.
As a rule of thumb, the bigger the amp, the more powerful it is. The size of the amp required depends on your system, and what you expect from it. If you're content with a basic system, a two-channel amp will work fine. But if you continually upgrade, you'll need the extra power and flexibility of a four, six or eight channel amp.
It is cheap, easy to fit and gives fantastic results.
Navigation systems utilize global positioning satellite (GPS) technology to pinpoint where you are, down to street level. Their updateable digital maps can direct you wherever you need to go.
Some systems integrate a traffic messaging service (TMC) recommending alternate routes whenever the unit receives a traffic alert.