Product Roundup: FM transmitters

Judging by Apple’s silhouette advertisements, you’d think the iPod was tethered only to slim youths devoted to dance. Not so. The world’s most popular go-anywhere music player is increasingly going everywhere in people’s automobiles. After all, where better to kill time listening to your favorite music, audiobooks, and podcasts than in a ceaseless traffic jam?

Yet placing an iPod in the car requires more than the will to do so. Because it’s unsafe (and illegal in most places) to listen to your iPod with headphones while driving, you must find a way to plumb the device into your car stereo. A direct connection via the dock connector or headphone port to an auxiliary input on the car’s audio head unit provides the cleanest sound, but not all head units include such inputs, and replacing them or adding an input via an external box can be expensive.

Cassette adapters can provide decent sound, but they can also be finicky—working perfectly in one cassette player and not at all in another. Plus the number of new car stereos including a cassette player is dwindling fast.

That leaves FM transmitters, devices that act as short-range FM radio broadcasters. Plug your iPod into one, tune your FM radio to an open (unused) frequency, switch the transmitter to that same frequency, and unsullied sound streams seamlessly from iPod to stereo. At least, that’s how it’s supposed to work. All too often, many of these transmitters are overwhelmed by more powerful radio signals or, well, whelmed just enough to make listening an unpleasant, static-filled experience.

How to tell the good from the not-so? That’s what we set out to learn by testing 30 of today’s more popular FM transmitters, ranging in price from $20 to $100. These devices offer a variety of features: Bare-bones models include a single stereo cable running to a flimsy-looking, AAA battery-bearing box that broadcasts to only a few frequencies. Others sport power connectors, transmit to more stations than are found on most radios, and, in one case, project track title information to the head unit of compatible car stereos.

Testing

Testing FM transmitters can be difficult because there are so many variables: How choked are the FM airwaves with competing signals in your area? How sensitive is a particular car’s antenna to the transmitter’s signals (and to outside interference)? How does shifting the position of the transmitter in the car change its performance?

Because we can’t ride in every car, equipped with every possible combination of head unit and antenna, in every location on earth, I set up a fairly simple testing procedure. First, I chose a 1996 VW Bug with a stock head unit as our test vehicle. I chose the Bug specifically because, from past experience, I knew that its radio is not forgiving of FM transmitters—only the most robust transmitters provide a clean signal when used with this car’s stereo. Anything less results in hiss and interference. If a transmitter performed well here, it should (fingers crossed) perform well anywhere.

I then chose a series of test frequencies. For transmitters that broadcast to the entire range of the FM frequency, I tested on 90.1, an “open” FM frequency not used by a radio station in our test area, and 107.9, a frequency inhabited by a local station with a strong signal. For those transmitters that broadcast outside the normal U.S. FM band, I also tested on 87.9, a frequency offered on some car radio’s (including the VW’s).

Some transmitters broadcast to a more limited number of frequencies—typically 88.1 to 88.9 and 107.1 to 107.9. With these transmitters, I used 88.1 as our “populated” frequency (or 107.5 if the transmitter didn’t support 107.9) as well as the “open” 88.7.

I performed the tests with a 5G iPod and a 4GB iPod nano. For those transmitters that accommodate both kinds of iPods, I tested each to be sure that one iPod model didn’t produce different results than another. (For the most part, they didn’t.) In those cases where a particular transmitters was designed for a particular iPod, I obviously used the appropriate iPod model for the tests.

Where possible, I moved the iPod and transmitter around in the car to try to improve its performance. For some transmitters, that wasn’t possible, as they were necessarily chained to the car’s cigarette-lighter receptacle or jammed into a cup holder.

Finally, I conducted the initial round of tests in my driveway. I then tooled around with those that had performed the best to see how the better transmitters performed in different locations. The tool-around test helped reveal subtle differences between these transmitters.

Features

The transmitters I tested vary in their range of features. Some broadcast on a very limited number of frequencies while others can access more frequencies than your radio can play. Some connect to the iPod’s headphone jack, wherease others use the iPod’s higher-quality dock-connector port instead. Most allow you to store and recall presets for easier navigation, but a few don’t. And some let you switch between stereo and mono broadcasting—a feature that can help the transmitter drown out competing frequencies, and achieve longer range, at the expense of true stereo sound.

Although I appreciate some of these extra features, my main concern was sound quality: Does the transmitter offer a clear signal? If not, all the features in the world aren’t going to make it a good choice. Our ratings are based largely on how a transmitter performs in this regard—for this reason you’ll see many 3-Play ratings, as many of the transmitters were average performers. If they were also easy to use, that was worked into our scoring.

Of the possible “extra” features, those that offer the greatest benefit include:

The ability to tune outside the normal FM band—specifically 87.9. “Regular” radio stations can’t use this frequency, thus ensuring that you’ll always have an open frequency to work with.

The ability to output a stronger mono signal.

The ability to store presets. Unsafe though it may be, you’ll be tempted to change frequencies while driving as interference kicks in. Far better that you push a button to switch to a clear station than take your eyes off the road and try to scroll station-by-station through the frequencies.

A dock connector connection. The iPod’s dock connector port puts out a cleaner, line-level audio signal than does the headphone port.

Cigarette lighter power. (Yes, we understand that the politically correct name for this 12-volt port is the “auxiliary power receptacle,” but everyone on earth know what you’re talking about when you refer to this receptacle as the “cigarette lighter port.”) Being able to charge the transmitter and iPod from the cigarette lighter ensures that you needn’t charge your iPod before taking it on a trip and saves you routine trips to the store to purchase AA or AAA batteries for your transmitter.

The transmitters

Here’s how the various transmitters shake out.

ABT iJet for iPod nano (

; $70). ABT’s transmitter offers frequencies between 87.9 and 107.9. Like Griffin Technology’s iTrip nano, Belkin’s TuneBase FM transmitters, and Kensington’s pico FM Transmitter for iPod and RDS FM Transmitter, the frequency is visible on the iPod’s screen. The case is similar to that of the iTrip nano and DLO’s nanoTune for iPod nano in that the case acts as an outer shell for the iPod with the transmitter incorporated into the bottom.

Unlike any other transmitter we looked at, this one includes an RF remote control that you use to manipulate most of the transmitter’s functions. (There’s also a small button on the side of the transmitter that you use to switch presets). It’s a cool idea, particularly if you’ve placed your iPod in a glove compartment or another area where you can’t easily access it. The iJet lets you store up to four preset frequencies.

The iJet is typical of these kinds of transmitters (i.e., small ones) in that it doesn’t have a lot of power. Its signal was clear but not terribly robust on the empty 87.9 frequency, but it was incapable of overpowering 107.9.

(Targus sells this same transmitter under the Targus RemoteTunes TC for iPod nano name for $80.)

Belkin TuneBase FM for iPod nano (

; $80). Belkin’s TuneBase FM for iPod nano is one of a number of transmitters where the iPod sits atop a flexible post that plugs into a car’s cigarette lighter outlet. The iPod connects to a dock-connector plug at the top of the unit. The TuneBase FM offers frequencies between 88.1 and 107.9, includes four preset buttons, and displays the frequency on the iPod’s screen.

This TuneBase performed well on the 90.1 frequency and was able to overpower the strong 107.9 frequency, though it flirted with interference quite a bit.

Belkin TuneBase FM for iPod (

; $80). Eighty bucks also buys you Belkin’s larger TuneBase FM. It offers the same features as the TuneBase FM for iPod nano but works with full-size iPods. Regrettably, it didn’t perform quite as well as its smaller sibling in our tests. It was a little hissy on 90.1 and very hissy when trying to overpower 107.9.

Belkin TuneCast II (

; $40). Belkin’s TuneCast II is an older product and performs like one. It supports frequencies from 88.1 to 107.9, uses the iPod’s headphone port rather than the cleaner-sounding dock connector, requires two AAA batteries, and offers four presets. In my testing, it was hissy on 90.1 and incapable of overpowering 107.9.

C. Crane FM Transmitter (

; $70). C. Crane’s FM Transmitter wasn’t built specifically with automobiles in mind—it’s really more at home in the house. With its boxy shape and telescoping antenna, it’s bulkier than the other transmitters we tested. It includes an AC adapter but requires two AA batteries to work in a car. It includes an input gain wheel that you can use to increase or decrease its output. It includes no preset capabilities. Though C. Crane’s website claims the unit can operate between 88 and 108, our unit runs from 88.3 to 107.7.

The FM Transmitter was very clear on 90.1 Because we couldn’t tune the transmitter to 107.9, we chose another populated frequency, 107.5. Although it was able to take over that frequency, there was some hissing and interference.

Digiana Audia X iTube-201 (

; $75). Digiana’s Audia X iTube is another “transmitter on a stick” that plugs into the iPod’s dock connector port and the car’s cigarette lighter. It, too boasts four presets and operates between 88.1 and 107.9. It played 90.1 fairly clearly but sounded overdriven. It was barely able to overpower 107.9.

DLO TransPod (

; $100). DLO’s TransPod is a good example of getting what you pay for. Among the most expensive transmitters we tested, it’s also among the most powerful. It’s on the bulky side, attaching to a cigarette lighter jack through a series of plastic joints. It features a dock connector, a large LCD display, four presets, and supports frequencies from 88.1 to 107.9.

We came to depend on the TransPod to overpower strong radio stations where other transmitters couldn’t. 90.1 was clear as was 107.9. In the “tooling around” test, the TransPod edged out Kensington’s very capable Digital FM Transmitter by stepping all over a powerful 88.1 frequency that caused interference on the Kensington unit.

DLO TransDock micro (

; $70). As much as we like DLO’s TransPod, the company’s smaller—and $30 cheaper—TransDock micro is the better deal. It too plugs into the “cigarette lighter” jack, but unlike the TransPod, it attaches to the iPod’s dock connector via a removable adapter cable. (Pull this adapter cable from the main unit and you’ll find that you can even plug in an iPod shuffle.) The micro offers four presets, includes an auxiliary output should you want to jack it into a cassette adapter or an Aux-In on your car stereo—although it beats us why you’d use a transmitter if you had an Aux In—and it includes an audio input of its own should you wish to play another device through the transmitter.

Like its larger sibling, the TransDock micro performed admirably with the stations we threw at it.

DLO nanoTune (

; $70). Unfortunately, DLO didn’t hit three for three in our roundup. The company’s nanoTune boasts many of cool features—a built-in FM tuner so you can listen to radio through the case that surrounds the nano, the ability to boost the nano’s volume by 25 percent, and, of course, an FM transmitter that supports 88.1 through 107.9—but it just doesn’t sound that great. For example, 90.1 was really hissy and the nanoTune couldn’t overpower 107.9.

Griffin Technology iTrip (

; $50). Griffin’s iTrip is the successor to one of the first FM transmitters for the iPod. This model plugs into the iPod’s dock connector, and you choose a frequency via a small toggle wheel on the unit’s right side.

What sets the iTrip apart from other iPod-powered transmitters are the combination of its LX mono mode and its ability to transmit to international frequencies. If it’s being overpowered by local stations, flipping the iTrip into LX mode can produce a clearer signal (albeit, in mono). And if your FM tuner supports frequencies below 88.1, you’ll be happy that the iTrip can broadcast to these frequencies when you configure it for International mode.

Although the iTrip’s playback was a little hissy on 90.1 (a bit better in mono), and it couldn’t overpower 107.9 (even when set to its mono mode), it sounded great on the VW Bug’s 87.9. If your car lets you tune to this frequency, the iTrip is worth considering. If it doesn’t, you can do better with one of the cigarette-lighter-powered transmitters we recommend.

Griffin Technology iTrip nano (

; $50). Griffin’s iPod nano transmitter was the first to offer a design where the nano sits in a small sled and shows frequencies on the iPod’s display (you tune the iTrip from the iPod as well). It offers the same unique features as the iTrip—mono mode and international frequencies—and performs very much the same way: 87.9 sounds great, 90.1 a little hissy, and no chance with 107.9. Kicking it into mono improved things slightly.

Unlike with the other iTrips, you can control the volume output of the iTrip nano with the iPod’s scroll wheel. If you overdrive the device, the iTrip will scale it back to a point before distortion kicks in. Very cool feature.

Griffin Technology iTrip Auto (

; $70). Griffin’s iTrip Auto performs the same tricks as the other iTrips—including mono and International modes—but it’s a wired device that sports a dock connector on one end and a charger you plug into the car’s cigarette lighter on the other.

Surprisingly, we didn’t get as good a signal from the iPod Auto as we did from the other iTrips. 87.9 was okay, 90.1 iffy, and it couldn’t touch 107.9. In this case the wired connection was the problem. With the other iTrips you can move the iPod and iTrip anywhere you like. Because the iTrip Auto is wired to the cigarette lighter, you’re more limited on where you can move the iPod to pick up a cleaner signal.

Griffin Technology RoadTrip (

; $90). Griffin’s not done yet. The company’s $90 RoadTrip is similar to DLO’s TransPod in that it’s a largish cradle with a dock connector that jacks into your car’s cigarette lighter. Unlike the other (and newer) Griffin transmitters, it doesn’t offer a mono mode nor will it work with frequencies below 88.1 or above 107.9. It also doesn’t offer any preset functions. On the other hand, unlike the iTrips, it could overpower 107.9, but was a little hissy. It sounded fine on 90.1.

CTA Digital 3 in 1 Car Kit (

; $30-$35). CTA Digital’s 3 in 1 Car Kit, sold at onine stores such as Amazon and Tiger Direct, is an odd looking beast. It clamps onto the iPod with a couple padded, extended arms—the arms are tight enough to hold a full-size iPod or an iPod mini but not a nano—and features a post that plugs into your car’s cigarette lighter. A dock-connector cable reaches up from behind the device to connect to your iPod. The 3 in 1 transmits on just four frequencies: 88.1, 88.3, 88.5, and 88.7.

The 3 in 1 fared well with a strong 88.1 in our test area, and sounded even better on the three remaining, untaken frequencies, but your mileage could easily vary—those limited frequencies could queer the deal if that portion of your local FM band is already crowded

i-Rocks i-Pod/MP3 Car DJ (

; $35). i-Rocks’ i-Pod/MP3 Car DJ is another catch-as-catch-can FM transmitter that plugs into the cigarette lighter, broadcasts on a limited number of frequencies (88.3 to 88.9), supports input from an iPod through the iPod’s headphone port, and lets you play music from an attached USB key drive. It performed well on its four frequencies—overpowering the strong 88.1—but, like all other transmitters with such limited frequencies, the Car DJ isn’t going to be a good fit for those who live in areas with crowded FM bands.

iRock Beamit (410FM) (

; $20). At $20, the Beamit (410FM) is priced to be disposable and, as such, isn’t a bad choice if you’re going to go on vacation and want to cheaply play your iPod through your rental car’s stereo. It requires two AAA batteries, broadcasts on 10 preset frequencies (88.1 to 88.9 and 107.1 to 107.9), and plugs into the iPod’s headphone port. In our tests it played fine on empty frequencies but didn’t fare well with those that were occupied by radio stations.

iRock Beamit (440FM) (

; $30). iRock’s Beamit (440FM) is a little more up-market, and $10 more expensive, than the Beamit (410FM). It supports two more frequencies than the 410FM—106.7 and 106.9—and includes a car charger, though you still have to plug the device into the iPod’s headphone port for sound. Like its sibling, it sounds fine with unoccupied frequencies. It was able to overpower 107.9 but with some hiss.

iRock 450FM (

; $40). The next price jump in the iRock line brings us the iRock 450FM. Unlike the less expensive iRock transmitters, this one offers the full band of FM frequencies—88.1 to 107.9. It also includes a car charger attachment, although the charger can be removed; you can instead use the unit with a AAA battery. Like the other iRocks, it uses the iPod’s headphone port and offers no presets.

Although the 450FM could overpower 107.9 with some hiss and played clearly on 90.1, its overall sound was flat, as if it was playing in mono.

Kensington Digital FM Radio & FM Transmitter for iPod (

; $80). Kensington’s Digital FM Radio & FM Transmitter for iPod is another hybrid unit, allowing you to both transmit your iPod’s output to an FM radio as well as listen to FM radio through the headphone port at the bottom of the unit while away from the car. It provides four presets and can transmit to the standard band of FM frequencies.

Although the Digital FM Radio & FM Transmitter provides a perfectly decent radio, it’s transmitting power isn’t so hot. It broadcast to 90.1 perfectly well but it barely overpowered 107.9.

Kensington FM Transmitter/Auto Charger for iPod (

; $60). Kensington’s FM Transmitter/Auto Charger for iPod is a limited-preset unit (88.1 to 88.7 and 107.1 to 107.7) that plugs into the cigarette lighter jack and your iPod’s dock connector. It handles clear channels well, but although it can overpower strong competing stations, it hisses in the attempt. Being tethered to the cigarette lighter makes it more difficult to find a “sweet spot” in the car.

Kensington Digital FM Transmitter/Auto Charger for iPod (

; $80). For those on the go who care about a clean signal, this Kensington transmitter is the best in the company’s stable. It offers three presets, support for the standard range of FM frequencies, pulls power from the cigarette lighter, and plugs into the iPod’s dock connector.

Only DLO’s Trans family of transmitters performed better than the Digital FM Transmitter/Auto Charger—the TransPod and TransDock micro just barely edged out the Kensington device in a test of a couple particularly strong competing radio stations.

Kensington Pico FM Transmitter for iPod (

; $55). By the time we got to Kensington’s Pico TM Transmitter for iPod, it was becoming pretty clear that the small transmitters that sit all by their lonesomes, clinging to the iPod’s dock connector, just aren’t very powerful. The Pico offers two presets, supports the full band of FM frequencies, and uses the iPod’s display for viewing station information. You use a small toggle wheel on the side of the unit to tune it. In our play tests the Pico was able to broadcast to 90.1, but the results were hissy. The mighty 107.9 refused to make way for the Pico’s weak signal.

Kensington RDS FM Transmitter/Car Charger (

; $90). The newest FM transmitter from Kensington, the RDS FM Transmitter/Car Charger, offers the unique feature of displaying song and artist names on radios—including some car stereos—that support the Radio Display System (RDS). The feature was lost on us as our VW Bug wouldn’t know an RDS signal if it crawled up and bit it in the behind, but those with compatible radios will likely be impressed. The RDS FM Transmitter/Car Charger offers three presets, handles the full range of FM stations, plugs into a car’s cigarette lighter, and displays station information on the iPod’s screen.

RDS technology is all well and good, but what matters is sound quality and this unit didn’t knock our socks off. 90.1 was clear, but although it could overpower 107.9, the resulting sound was fuzzy.

MacAlly IceFM (

; $30). Macally’s IceFM is another limited-frequency (88.1 to 88.7) cigarette lighter/iPod headphone port transmitter. It includes a female USB port that you can use to charge your dock connector iPod with your iPod’s USB cable. The IceFM’s audio performance was underwhelming, suffering from interference on 88.1 and a fair amount of hiss even on clear frequencies.

MacAlly FM Cup (

; $60). Macally’s FM Cup takes the unique approach of housing the FM transmitter inside a cup-holder attachment. Plunk the iPod into the Cup’s dock connector, string the included cigarette lighter attachment between the FM cup and your car’s power (cigarette-lighter) receptacle, switch it on, tune it in, and you’re ready to rock. It doesn’t offer any presets, but does include a second audio input for listening to another source.

Because it’s designed to fit inside one of your car’s cup holders, you have limited options for moving the FM Cup into a sweet spot. Regardless, it performed pretty well in our tests: 90.1 came through solidly and the Cup overpowered 107.9 without a lot of hiss.

Radian Technologies iBlast FM for nano (

; $50). Radian’s iBlast FM for nano is a capable iPod-nano-on-a-flexible-stick device that plugs into your car’s cigarette lighter and your iPod’s dock connector. Like some of our other favorite units, this one broadcasts on 87.9. It also offers 5 presets.

The iBlast FM performed solidly with 87.9, well with 90.1, and managed to overpower 107.9 with a little interference.

Sonnet PodFreq (

; $100). Sonnet Technology’s original PodFreq models—for older full-size iPods and the iPod mini—were once the transmitters by which we measured others. No longer. Although the current PodFreq, identical to the original except for iPod compatibility and included accessories, remains a reasonable choice for the home because of its design—it encases the iPod and pulls power from the iPod’s battery—it’s not the best option for your car. To begin with, it doesn’t cover the entire FM band—88.1 and 107.9 aren’t offered. Secondly, there are no presets. The PodFreq does, however, include a car cradle and a plug-in auto charger, which help take some of the sting out of its high price. But it failed to provide the kind of power displayed by our favorite DLO and Kensington transmitters, performing well with 90.1 but barely overpowering a strong 107.5 signal.

Sonnet PodFreq nano (

; $100). Sonnet’s PodFreq nano is an update to the PodFreq design. In addition to providing a sleeker case, it fills in the frequencies omitted by the larger PodFreq—88.1 to 107.9 are fully represented. Like the PodFreq, it includes a telescoping antenna, auto charger, and car cradle (as well as a soft carrying bag). It also doesn’t offer any presets.

As did its older sibling, the PodFreq nano locked in on 90.1. It also overpowered 107.9, but with some interference regardless of where we moved it in the car.

Virtual Reality Sound Labs MP3 WMA FM Modulator (

). The MP3 WMA FM Modulator was one of the pleasant surprises of our survey. It’s an inexpensive transmitter that plugs into the cigarette lighter and connects to the iPod via the headphone port. Like iRocks’ i-Pod/MP3 Car DJ, the FM Modulator can play music from an attached USB key drive. It transmits to only 12 frequencies, but those frequencies fortunately include 87.7 to 88.9 and 106.7 to 107.9. If your radio can tune below 88.1, this transmitter can broadcast to it.

For such an inexpensive device the FM Modulator put out a decent signal. It nicely overpowered 107.9 and was clear on the unencumbered 87.9.

XtremeMac AirPlay 2 (

; $50). XtremeMac’s AirPlay 2 is yet another example of a small, dock-connector based transmitter that just doesn’t have the power to perform. It includes some welcome features—the ability to access all normal FM frequencies, three presets, and a mono mode that helps with interference—but it sounded only okay with 90.1 and barely overpowered 107.9. It also felt a little bulky and insecure dangling from the bottom of the iPod.

The lowdown

Our findings didn’t completely surprise us: No transmitter matched the quality of a direct iPod-to-stereo connection. And smaller invariably meant weaker—the diminutive, standalone transmitters that clip to the iPod’s dock connector put out only an average signal (though they offer the advantage of portability that the cigarette-lighter-locked models only dream of). But we were interested to discover that while many of them produced mediocre results when faced with a strong competing signal, a few muscled through the interference.

For pure power, DLO is the current king of iPod-compatible FM transmitters. Kensington gets close with its Digital FM Transmitter/Auto Charger for iPod, but the TransPod and TransDock micro have a slight edge when a strong radio station wishes to take over a frequency. If DLO’s asking price of $100 is too much and you have a nano, the iBlast FM for nano is a good choice.

With their portability, ability to broadcast in mono, and tune down to 87.9, Griffin Technology’s iTrip and iTrip nano are also worth your consideration (though we were less impressed by the performance of the iTrip Auto). If your car radio tunes to 87.9 and you’d like to control your iPod while it’s tucked away in the glove compartment, the iJet for iPod nano (a.k.a., Targus RemoteTunes TC for iPod nano) is a reasonable option. And finally, if you’d care to do it on the cheap and have a radio that tunes to 87.9 (or have a moderately vacant FM band where you travel), the MP3 WMA FM Modulator isn’t a bad way to go.