In order to give you an even better idea of the comparative performance of various FM transmitters we recently compared, we’ve put together two tables for your viewing pleasure, and expanded our previous findings with additional test data and details.
The first table, Portable FM Transmitters, looks at the same six transmitters we picked for our shootout. But now we’ve added a new test designed to give you an idea of how each transmitter does on a “good” local station. Any transmitter that could tune to 87.9FM – the most common “empty” station in the United States – was tuned to that station. Those transmitters that could not were tuned to 88.5FM instead. And this time, we tested at a distance of 15 feet from the radio so that you will know how each device does on a relatively good station under greater distance strains.
Separately, a new section titled “Static Level by Distance,” gives you an idea of how much static you can expect to hear on 87.9FM/88.5FM at various iPod distances from radio. Additionally, our iPod (Color) Battery Drain row gives you a snapshot of the battery hit today’s iPods will take using these devices, while current price shows you how much you’ll pay. As you’ll see, the final version of Griffin’s iTrip (LCD) comes out strong, though Tekkeon’s expensive MyPower FM solution is capable of very low static levels at various distances.
Our second table, In-Car FM Transmitters, also looks at the same six car-only transmitters we picked for our shootout. We’ve also added a new test here, giving each device a chance to perform on clear station 87.9 if possible, or 88.5 if not. Key features and issues of each car transmitter are identified, as well, along with prices.
Conclusions and additional details on the final version of Griffin’s iTrip (LCD) follow below the tables.
Notes on Methodology
FM devices tested at various distances were not permitted to be hand-held during testing, which would influence (and positively skew) test results. Portable units were tested without significant obstructions on a direct visual line from the digital radio tuned to their respective stations.
Table 1: Portable FM Transmitters
| Belkin TuneCast II | BTI The TuneStir | Griffin iTrip (LCD) | Griffin iTrip (no LCD) | Tekkeon myPower FM | XtremeMac AirPlay | |
| Indoors, 103.3FM, 3 foot distance | Static very audible when silent or playing, bass clipping (distortion) noticeable during playback. | Static audible when silent, occasional high-pitched noise. Static isn’t very noticeable during playback, but sound is flat. |
In silence, static level very low in DX (mono) mode, comparable to std. iTrip in LX (stereo) mode.
In playback, clean. |
Above avg. static audible in silence, avg. in playback, but sound quality is good. | Static audible in silence, high-pitched sound noticeable. During play, static + bass clipping noticeable. | Static audible in silence, but high-pitched sound appears, remains during playback as silence becomes less noticeable. |
|
Indoors, 87.9FM/88.5FM (87.9 if supported, 88.5FM if not), 15 feet. |
88.5. Very staticy, mix of music and static with music taking slight edge, faint high-pitched sound evident. | 87.9. Alternates. At times, lots of static, other times, very clear, seems sensitive to movement. When clear, music is flat. | 87.9. DX mode is completely audible with light static. LX mode is a little better than std. iTrip, static still noticeable but music dominates. | 87.9. Comparable to TuneCast II, except for high-pitched sound (not here), very staticy with mix of music and static, music a hint stronger. | 87.9. Static level low, but high squeal noise audible at all times, every beat of song is scratchy, bass clipping evident, and sound otherwise is flat. |
88.5. Medium level of static when silent, but during play, static low, strongly dominated by music.
High-pitched sound occasionally warbles in/out. |
| In car, 103.3FM, near stereo. | Static very audible, and strong in music. | Static is above average, quite noticeable during playback. | In DX (mono) mode, static is light to medium during silence and playback. In LX (stereo) mode, signal fades in and out. | Static audible in music, but sound is good otherwise. | A high-pitched sound and avg. static are audible when silent, static and bass clipping when playing back. | Virtually unlistenable unless car charger is connected; a bad station for AirPlay. |
| iPod (Color) Battery Drain | None. Uses internal AAAs. | Goes from 17 hours down to 7.5, a 56% reduction. | Goes from 17 hours down to 11.5, a 32% reduction. | Goes from 17 hours down to 10, a 41% reduction. | None. Requires myPower external battery pack. | Goes from 17 hours down to 10.5, a 38% reduction. |
|
Static Level by Distance (Note: static can be reduced in all but MyPower by connecting cable.) |
8 feet: 10-15% 14 feet: 50% 20 feet: 66% 30 feet: 95-100% |
8 feet: 20-50% 14 feet: 50% 20 feet: 100% |
8 feet: 15-25% 14 feet: 25-50% 20 feet: 25-50% 30 feet: 100% |
8 feet: 15% 14 feet: 15% 20 feet: 25% 30 feet: 100% |
8 feet: 5% 14 feet: 15-20% 20 feet: 15-20% 30 feet: 33-40% |
8 feet: 15-25% 14 feet: 20-25% 20 feet: 25-33% 30 feet: 95-100% |
| Current Price | US$39.99 | US$69.95 | US$39.99 | US$35-$39.99 | US$34.95 (+$89.95 battery) | US$39.95 |
Table 2: Car-Only FM Transmitters
| Belkin TuneBase FM | DLO TransPod FM | Griffin RoadTrip | Kensington Digital FM Transmitter Auto Charger | NewerTech RoadTrip! Plus | NewerTech RoadTrip! 87.9FM | |
|
In car. 87.9 if supported, 88.5FM if not. |
88.5. Pulses of quite audible static aren’t objectionable overall, but come on and off at light to mid level. | 87.9. Light static with occasional pulses based on music playback. Higher static level than RoadTrip! 87.9, but not by much. | 88.5. A bit higher in static level than best we heard, but markedly lower than TuneBase FM. | 87.9 tuned with secret command. Light oscillating static, but sound is very bold and dynamic – best apparent dynamic range overall. Without secret command, 88.5 tunes in quite staticy. | Low static level but slight high-pitched warble sound evident, slight cable noise in audio if moved. Audio sounds strong regardless. | Low static level, but demands iPod volume adjustment to get strong sound. Not as dynamic as Kensington but volume can be tuned to increase signal to noise ratio above TransPod FM level. |
| In car, 103.3FM, near stereo. | Most static of any in-car options we tested when silent; static and bass distortion audible during music playback. | Audible static when silent and when playing, plus bass clipping during playback. |
