Keep on Trunkin'

3 Ways to Add a CD Changer

Car CD units are controlled through the radio (called the ''head unit''), and unless you have a 1990 car or have changed radios recently, yours probably isn't CD-compatible. To upgrade, over and above the cost of the CD changer, you have three choices:

THE QUICK AND DIRTY Get an FM modulator, a small, inexpensive (about $20) gadget that lets your CD changer play through your FM radio as soon as you tune to a certain station. Don't let anyone tell you the sound is as good as it is with the other methods — it's not. All you get is the convenience of playing CDs while you drive. You also will need a control unit, called a commander or controller, which takes charge of the changer when the discs are playing (about $100-200).

THE BUILDING BLOCK You go for an AM/FM cassette player with CD ''input'' (about $300 and up) — the CD changer is wired to plug into the cassette player — and a commander (see above). Almost any brand of CD changer and commander will be compatible with the cassette deck you choose. The radio controls the volume, bass, and treble. Later, you can add new parts, such as a new amplifier or better speakers.

BITE THE BULLET You get a new radio with AM/FM, cassette, and CD ''control'' (about $600 and up). Arguably the best approach. Get the same brand radio as CD changer, and save your old radio for when you sell your car, in case you want to reinstall the system in your next car.

Labor costs for switching radios and installation charges for the changer should total under $200. About 70 percent of people choose the third option, and 30 percent the first two, according to Robert Heiblim, Denon executive vice president.