Car owners guide to: Car Audio > MP3 & Ipods

MPEG-1 Audio Layer 3 - or MP3 as it's more usually called - was dreamed up by a team of European engineers as they were working on the DAB digital radio project. It's a method of recording and storing audio digitally in such a way that each music track takes up considerably less memory space than when using other types of recording (or 'encoding') techniques. The result is that a lot more music can be stored on a CD or on the memory chip or miniature hard-disk of an audio player, such as Apple's iPod™, probably the best known of all the portable music players.

Lossy Audio Formats

MP3 is what is known as a 'lossy' compression format. Some of the finer detail in the audio track is ignored and the remaining data is encoded in a very efficient way so that the stored music retains the essential parts that keep it sounding true-to-life, but it now fits into a much smaller memory space.

While some clever psychoacoustic rules are applied to decide what bits get ignored, it's unavoidable that MP3 (and other lossy compression formats) will never quite match the audio quality of the original sound recording.

Where maximising data memory is important (such as with small portable devices), MP3 provides a good solution. But with a more revealing playback system, such as a power amplifier and a good quality speaker system instead of earphones, the limitation of the MP3 format becomes more evident. This is especially true if you compare the sound with the same music track played from a pre-recorded CD.

Portable MP3 players have revolutionised the way we listen to our music as we travel on trains, planes and buses, walk, jog and even while we work. More and more people, having put perhaps their entire music collection on to their MP3 player, are then tempted to hook the player up to their home and in-car system. It has become a very popular thing to do. But these are first and foremost convenience devices where sound quality is, to some extent, sacrificed for portability.

In particular, sound quality at the extreme ends of the scale (sub bass and highs) will be noticeably less impressive than from uncompressed CD recordings. The sensation of air and space around the musical instruments and singers' voices tends to be lost. It simply doesn't feel quite so 'alive'.

Adding your iPod™ or other MP3 player In-Car

So okay, MP3 and similar digital formats are not ideally suited to high-fidelity music listening, but that clearly doesn't worry a lot of people. Its convenience wins out big time, and the sound quality is good enough in normal use. Not surprisingly, many people want to be able to use their digital music players in-car.

Several of the newer CD players have a 3.5mm stereo input socket or a USB connector. If you still have a cassette player in the car then you could buy one of the wired cassette tape adaptors, or an FM modulator that allows you to tune the MP3 player to a vacant FM radio frequency slot (that way there's no need to have a wire to carry the sound to the car stereo unit). Both these latter solutions connect to the MP3 player's headphone socket (though some FM adaptors include iPod's 30-pin universal connector, which is generally better if you have an iPod™). These work okay, but not brilliantly well - you'll lose a little more of the audio quality because of the way the sound has to either pass through the cassette player's tape head or the FM radio tuner. Using Bluetooth A2DP can work quite well and may win for its convenience, but you'll still lose some quality.

The best way is to use an adaptor designed to take the digital output from the iPod™ (via the 30-pin connector) and inject it into your car's music system. These devices will often also provide some kind of docking station for the player to fit on to, providing a secure mounting solution.

An increasing number of CD and multimedia in-car head units are "iPod™ Ready", meaning that the iPod™ can be controlled from the head unit, with the iPod's music album/track information shown on the head unit's display. Some will also play the iPod's video files on their screen, and allow the audio and video signal to be sent to external monitors, in the rear headrests for example.

There are now lots of solutions for integrating portable music players electrically and physically in to your vehicle. Ask your local InCar Expert for advice.