Pros: Great sounding in-car FM radio transmitter and iPod charger with easy to read backlit screen and simple controls. Better overall audio quality than virtually all of the FM transmitters we’ve previously tested.
Cons: Very pricey for a FM transmitter at full MSRP, even considering charger’s included – shop around. Slight sibilance in audio. Only functional in a car.

For months, we’ve inserted a warning into every FM transmitter review we’ve published: use an FM transmitter only if you have no other iPod-to-stereo connection options, and don’t expect the sound to compare in clarity or quality to any wired connection. Today, that warning’s on the verge of extinction: Kensington’s Digital FM Transmitter/Auto Charger ($79.99, street price $53 and up) delivers wireless audio quality that’s as close as we’ve heard to a wired connection. As it’s integrated with a car charger, it also recharges your iPod’s battery at the same time.
Kensington’s aesthetic design is simple: the Digital FM Transmitter is a white and gray plastic plug with a LCD screen, four white buttons, and a white cable coming out of its left side. You plug the unit into your car’s power adapter, then connect the cable to the bottom of any Dock Connector-equipped iPod – 3G, mini, or 4G/color/photo.
As with all FM transmitters, it’s intended to broadcast your iPod’s audio to any vacant FM station on a nearby stereo, and this one is best used by people whose cars don’t have cassette tape decks or auxiliary audio inputs.
What’s special here is the Transmitter’s internal design. Even by comparison with other FM transmitters we’ve recently liked on audio quality, such as Newer Technology’s RoadTrip!+ (iLounge rating: B+), the Digital FM Transmitter’s sound offers clarity and detail that we hadn’t expected to hear without wires. Kensington’s sound is so good, in fact, that we flipped back and forth between the radio and a simultaneously connected Sony cassette adapter, and though the Sony had an edge (mostly in base-level noise), the difference between the two was smaller than we’ve ever heard before.
Kensington attributes its sound quality to Aerielle, a digital wireless technology that the company claims “enhances noise reduction and stereo separation.” We agree with both claims. While not up to the near-silent standards of the best cassette adapters or the true silence of direct line-in stereo connections, the Digital FM Transmitter’s base level of noise – what you hear when no music is playing – is lower than virtually all of the alternatives we’ve seen. Left and right-channel sounds were distinct and clear in our tests, though the separation wasn’t as surprising as the crispness of what we heard. Combined with the fact that it’s pulling audio from the iPod’s cleanest output – its bottom Dock Connector port – Aerielle delivers sound that’s powerful and quite accurate.
We were also generally quite impressed by the Digital FM Transmitter’s tuning functionality. As with a number of other digital FM transmitters, this one includes a backlit LCD screen and a digital tuner that toggles from 88.1 to 107.9FM, with three preset buttons to memorize and return to stations you prefer.
The blue backlighting is bright and easy to read, and the up and down tuning buttons are easy to use. Regrettably, the Transmitter doesn’t tune down to 87.9, which as we’ve noted in prior reviews has a strong chance of being empty all across the United States, but it does a very solid job on any other clear station it finds.
There are only two issues we noticed in testing the Digital FM Transmitter – one small, one bigger. First, as with all FM transmitters, its audio isn’t flawless: while tight on both the treble and bass sides, this one exhibits a small hint of sibilance, or exaggeration of “s” sounds, which we’re guessing is attributable to slight treble enhancement by Aerielle. When we say “small hint,” we mean to emphasize that this is not a deal-breaking issue in our minds – every FM transmitter has some sort of issue, and we’d sooner take this one than flatter, muddy audio any day.
Second, the Digital FM Transmitter is – at full retail price – quite expensive. It’s unquestionably a better product than the Newer Technology RoadTrip!+ we liked, but at more than twice the price, it should be. The only other FM transmitter we’ve seen in this price range is Sonnet’s even more expensive PodFreq, a bulky, antenna-laden box which we actively disliked and didn’t find to perform especially well for the dollar. Kensington’s product avoids all of the PodFreq’s design mistakes, but at $79.99 will scare a fair number of people away given competitors in the $30-50 range.
The price is moderated by two factors: the Digital FM Transmitter’s built-in iPod battery charger, which worked properly in our testing with various iPods, and the fact that street prices for Kensington products are often $20-30 below their stated retail levels.