Is Your iPod AUX In, or AUX Out?

The key here is to find the best way to send your iPod's MP3 audio signal, which typically comes out of the headphone port, to your car's audio system. You want the sound quality to be good, but the setup should also be pretty easy and not too expensive. Which way is the best?

One interesting way to listen to an iPod in the car isn't directly through any wires or dock, but wirelessly through an FM transmitter. There are several of these devices available through third-party developers, including the Griffin iTrip, the iCarPlay and the Roadmaster. FM transmitters simply plug into your iPod's headphone port and transmit the audio signal to the radio's receiver over the FM frequency. Although they're relatively simple to set up and use, the biggest downside to FM modulators is sound quality and interference. In certain places, especially cities with lots of FM stations, the device's weak signal can compete with other signals, and the result can be a jumble of static. In addition, as you drive you may find stations that interfere with your FM modulator's signal as you enter new broadcast areas.

FM modulators, on the other hand, have an advantage over transmitters. Instead of relying on surrounding radio frequencies, a modulator plugs directly into the back of your car radio, using its signal to play music through your stereo. This eliminates static and makes the sound much clearer. The only issue casual iPod fans might have is that you have to remove the radio unit entirely to install the modulator -- so it's not the simplest solution to playing music in the car.

Using a tape cassette adapter through a cassette deck is a simple and effective way of playing an iPod in a car. All you have to do is insert the jack into the iPod's headphone port, slip the cassette in and you're ready to go with fairly good audio. The one problem in using this method -- car manufacturers stopped equipping cars with cassette players a while ago, and a lot of people have replaced old cassette decks with CD players, anyway. It's a great option if you actually have a tape deck, but an adapter won't do you any good if you don't have one. Tape cassette adapters also have a tendency to make some noise, and once you finally notice the sound of those spools spinning, it may be hard to ignore it.

So the previous options have their strengths and weaknesses, but the best way to listen to your iPod in the car is also the simplest -- using the auxiliary input on your car's stereo. Most car radios and CD players made these days have an auxiliary input somewhere on them. If your car stereo has this feature, all you should have to do is purchase a patch cable, plug one end into the iPod's headphone port, plug the other end into the radio's auxiliary input and switch the system's settings to AUX. This will provide the best sound quality and it's a simple setup, too.

One downside to an auxiliary input is a lack of power: While some options, like an iPod dock, allow you to charge the iPod while you listen, a patch cable only does the job of sending the audio signal to the player. If your vehicle is equipped with a cigarette lighter or a power port, both Apple and third-party developers offer chargers that allow you to recharge your iPod in your car. And if you're worried about your iPod sliding around your car and getting scratched, it might be a good idea to get a mount to keep it in place.

For lots more information on iPods and autos, cruise comfortably to the next page.