The TrueFit 4 is among the most accurately balanced in-ear headphones Playback has yet sampled. Perhaps the only slight deviation from strict textbook accuracy would be a very subtle hint of bass emphasis, which we regard as an intelligent design compromise that actually helps the headphone sound more accurate in environments where there is low-frequency noise present (which, come to think of it, is most environments).
One area of the audio spectrum that the TrueFit 4 handles particularly well is the potentially tricky upper midrange/treble region—a region many earphones get wrong. What the TrueFit 4 manages to do is to sound articulate and well extended, yet without becoming edgy, brittle or overly bright. Similarly, it also manages to serve up a welcome touch of treble smoothness, but not at the expense of sounding dull or rolled off.
But good though the TrueFit 4’s tonal balance is, its greatest strengths may lie in other more qualitative aspects of sound reproduction. The TrueFit 4 actually offers a well-integrated package of sonic virtues, including good transient speed, high levels of resolution and detail, a highly articulate sound overall, and excellent handling of both large- and small-scale dynamic contrasts. Put these qualities together and you wind up with a sound that is remarkably vivid and vibrant—the very words I would use to describe the sound of good custom-fit in-ear monitors.
Does this mean the TrueFit 4 is truly the equal of custom-fit monitors? Not exactly, and here’s why. First, the TrueFit 4’s noise isolation, though very good as universal-fit earphones go, is not as good as the isolation afforded by custom-fit designs (nor should we expect it to be, given the huge price differentials involved). Similarly, the TrueFit 4’s sound, whose articulation and vividness place it near the top of the universal-fit class, nevertheless falls a little short of the performance that, say, Westone’s nearly twice as expensive ES5 custom-fit monitors can deliver.
But let’s put things in perspective; the TrueFit 4 is easily one of the three or four best universal-fit earphones Playback has ever tested (the others are the Monster Turbine Pro Copper Edition, the Sennheiser IE8, and the Shure SE535). What is more, one could make a strong argument that, with all factors considered, the TrueFit 4 is the most well rounded performer of the bunch. Thus, if you want a big taste of what custom-fit sound is about, but without paying the inevitable custom-fit price, consider the TrueFit 4, which really does push the limits of universal-fit technology.
Most of my listening tests for this review were conducted using an iPod Classic loaded with lossless files, with signals routed through a Moon Audio Silver Dragon LOD (line out dock) cable to an ALO Audio Rx MkII portable headphone amplifier.
Additional listening involved lossless digital files played from Windows PC though a Furutech GT2 USB cable to a NuForce Icon HDP USB DAC/headphone amplifier.
Still other tests involved CDs and SACDs played through a Musical Fidelity kW SACD player, with signals routed through Rega Couple interconnects to a Burson Audio HA-160 headphone amplifier (sometimes used with Burson Audio’s AB-160 tube buffer, sometimes not).
A test track that has been in heavy rotation on by iPod for the past several months is “Joanni” from Kate Bush’s Aerial [Sony]. The song can be viewed as a hymn of sort to Joan of Arc, but with a distinctly modern twist in the form of a driving, heavily syncopated, and eerily propulsive instrumental theme (carried by both high and low percussion, strings, and a variety of other instrumental flavorings), which is juxtaposed against Bush’s sometimes delicate and ethereal, but sometimes earthy and almost guttural vocals. The mix, obviously, features a lot of textures and tonalities being pushed forward at once, so it makes a formidable workout for any headphone.
The TrueFit 4’s did a fine job with the track, starting with their ability to capture the deep, plunging “thwoomp” of the low percussion notes that set the song’s pulse, while at the same time doing a good job with the sparkle and shimmer of high percussion accent notes. About the only thing lacking was that elusive, Nth degree of treble definition, focus, and openness that can—through the very best headphones (whether in-ear or full-size)—let the sounds of the high percussion instruments take on a life of their own, with notes lingering on the air long after notes have been struck.
But what was really impressive was the way the Westones handled Bush’s deceptively difficult-to-reproduce voice. The trick is that it is easy to overdo the upper register of her voices, as on the lead-in line of the song’s chorus, where Bush soars up high to sing, “Whoooo’s that girl?” But happily the Westones nailed this line, letting it soar without adding any overwrought edge of their own.