For the purposes of this review, we’ll put aside the question of who’s at fault — car makers, accessory makers, or both — for creating “alternator whine,” what Griffin describes as “the high-pitched whine of ground loop noise,” which “can result when you charge your iPod as it plays in many automobiles.” The key word here is “can,” so if your car and your iPod car kit have been designed properly, you’ll have no need for Griffin’s new Noise-Reducing Audio Cable ($20), a six-foot, gray and black cable, with a shiny black noise filter box two feet from one of the cable’s two 3.5mm plugs. But if you’ve heard this noise in your car, as we have with iPods and iPhones in an aux-in-equipped Toyota Highlander — one of a number of models with known issues — the new Noise-Reducing Audio Cable will help. Whether you want to bother with it is a separate question.
Notably, the noise we’re talking about isn’t the high-pitched “TDMA interference” that comes from first-generation iPhones and EDGE-locked iPhone 3Gs as they play in some automobiles; this is a quiet, high-pitched squeal that appears to change in pitch or intensity as you accelerate. We’ve heard this noise in a number of cars, but it’s easier than TDMA interference to ignore: it’s generally only evident during quiet or silent parts in audio playback, and even so, it’s high-pitched enough that some ears won’t even know it’s there unless it’s specifically pointed out.
Serious listeners, however, may care, and it’s for them that the Noise-Reducing Audio Cable has been designed.
We tested Griffin’s cable against other cables in our arsenal, including one that was directly integrated into the Kensington LiquidAUX charger for audio output. LiquidAUX, like many if not most other chargers with integrated audio-out, puts out an otherwise clean signal from the bottom of the connected iPod or iPhone, but you’ll sometimes hear the aforementioned squeal in cars with the issue. During an extended drive, we swapped back and forth between the Noise-Reducing Audio Cable, and found that it unquestionably eliminated the noise, as promised; otherwise, there was no discernible difference between the music played through our test iPhone and the other cables.
Across a bunch of different songs we tried, Griffin’s filters appeared to be removing just the interference, so though it’s possible that some songs may be modestly degraded, we didn’t hear any evidence of this. For those who may be curious, the TDMA noise isn’t increased as a result of using this product, which has plugs shaped to fit the original iPhone’s recessed headphone port; it was, as with virtually every iPhone-specific product we’ve tested, barely audible during silences, and then only when the volume was turned up to above-average levels.
Our only issues with the Noise-Reducing Audio Cable were two in number. From a physical standpoint, we found the six-foot length of cable to be way more than was necessary, and while whatever’s in the big black box in the center worked as it should have, it and Griffin’s 3.5mm plugs are undeniably too large by reference to basically everything else that we attach these days to our in-car audio systems. Second is the “blame game” issue noted in this review’s introduction: whether it’s the car makers’ fault for making whine-susceptible cars, or the accessory makers’ fault for making whine-provoking accessories—a question we plan to examine further next week—a big, filtered, $20 audio cable may solve the problem, but hardly seems like the optimal way of doing so.
