Playing music from a portable MP3 player in the car has always seemed obvious but for early adopters, it's been a struggle until recently. One increasingly popular alternative is using FM transmitters that broadcast the music signal from your player to an unused frequency on your car's radio. I have tried three different gadgets that are all supposed to achieve the same result but have discovered that there are quite a few things to consider when shopping for a FM transmitter solution.

Three Different Approaches

I have had the chance to use the following products with varying degrees of success and satisfaction:

• irock! Beamit 300W


• Belkin Portable Music TuneCast II


• DLO TransPodFM

As I will explain below, there is a lot more to this seemingly straightforward mobile solution than you might think.

Power: Batteries vs. Cigarette Adapter

There are two primary sources of power in the car - the built-in lighter and plain old batteries. Batteries are fine for some devices like Gameboys or flashlights but for extended use, you need to step up to car chargers. The iRock only offers a battery option which is what makes it a really cheap option - if you don't count all the batteries you will buy over time. The Belkin offers both, which is interesting if you are planning to use it away from the car, too. But, the device's power has a huge impact on the strength of the FM transmission, so degrading batteries can negatively influence your listening pleasure.

The DLO unit was by far the best solution for power, offering two different lighter adapters, one for the fixed, mountable cradle and another with an extension cable for harder to reach lighter plugs.

Messy Wires

You would think that since we are talking about using wireless transmissions, the results would have fewer wires than, say a cassette adapter or auxiliary audio plug, but that has been the fallacy of nearly all wireless solutions. The self-powered iRock was actually ok using only a single, short wire to plug into the headset of the player. The DLO's cradle option was ideal as there are no wires at all! But, the Belkin created a mess, requiring multiple cables to connect the various pieces of the total assembly.

Preset Stations

There are actually quite a few unused frequencies on the FM dial that can be used by FM transmitters like those discussed here. Each unit allows you to tune up and down the "dial" to find another unused frequency. The better units like the DLO come preprogrammed with well-known frequencies like 88.1 or 94.7 already programmed in, and provide buttons to recall them quickly.

If you live in an area with a busy FM landscape, you may find it necessary to jump around between frequencies as you travel. I recommend programming some of the better frequencies into your car's radio so that they can be quickly synchronized with the FM transmitter. Getting interference? Simply hop over to the next "free" frequency and switch the transmitter to match the radio's new setting.

Player-Specific vs. Generic Headphone Adapter

An attractive feature of the iRock and the Belkin units are that they are completely device-independent relying only on a headphone (or line-out) jack on your device for sound. This means that they are just as happy transmitting sound from a PDA, computer, or video game as they are from an MP3 player, making them very versatile.

Other device-specific solutions limit your options by plugging into proprietary hardware jacks. The DLO unit I use, for example, only works with Apple's MP3 players, but does provide adapters for both the full-size and mini iPods. If you are already heavily investing around a single product (e.g. custom cases, power adapters, etc.), then this probably won't seem like a big deal. If you are like many of us who have had it with proprietary car chargers for each new cell phone, then this new type of lock-in may frustrate you even further.

Finding a Home for Your Gadgets in the Car

And finally, the issue of "where is all this going to live in my car?". Portable player manufacturers seem to think only about how well the device will fit in your pocket and leave it up to the after market geniuses to solve the car and home mounting problems. But here is where, I think, the real differentiation comes in. If you are planning on using your player in your car often, you are likely going to want to have immediate access to it at all time - especially as you will probably be controlling the music from the device itself and not through your car's built-in radio, steering wheel controls, or remote control.

This is where the DLO and options like it really shine. Where the iRock and Belkin chose a minimalist approach, they provide no assistance with the placement of the player, and in fact make it worse by requiring you to additionally balance the second unit dangling off the player. I have found that this takes away from any elegance offered by the portable player and kills the whole in-car music experience.

The DLO unit, however, changed all that and immediately restored my faith in mobile MP3 music. The DLO unit includes a cradle which, as mentioned above, only works with iPods, but the cradle is connected to the car charger by a flexible arm that solves the power and mounting problem in a single stroke. If you have a cigarette lighter anywhere in the dash or instrument panel, you can quickly mount and position the iPod in the DLO cradle so that it's out of the way and easy to operate. There are no wires, no gadgets sliding around, and the thing actually charges your iPod as a side benefit!

The Verdict

It is pretty easy to see why I preferred the DLO unit and I would highly recommend it to all iPod owners, although be warned that it is not the cheapest solution out there. Still, it offers the best wireless sound option that I have heard, and addresses many mobile audio problems (power, placement, usability) with an elegant solution.

Also remember that there are other factors to consider when exploring FM transmission, such as the physical distance from the transmitter to the car's own antenna, which is how the signal is ultimately getting to your speakers.

FM transmitters are becoming much more prominent in portable media gadgets, and will likely only improve as time goes on. My overall advice is to consider all your options for playing audio in your car, and there are many beyond FM transmission.

Purchase the dlo Transpod mentioned in this article.