Given the X10i’s diminutive size, you might think it would produce a tiny, restrained or “petite” sound, but exactly the opposite is the case. The X10i produces a big, smooth, full-bodied sound with generally ample bass and excellent natural clarity, though it is not the last word in absolute bass or treble extension (at least not relative to the strongest competitors now on the market). More so than many in-ear headphones, however, the X10i possesses a certain effortless richness that makes its sound immediately accessible and easy to enjoy for hours at a time.
Tonal balance is nearly neutral, though some might find it just slightly tilted toward the “warmth” end of the audio spectrum. There is little if any of the midrange forwardness you might hear in, say, Klipsch’s Image S4i; instead, the X10i’s midrange is evenly balanced and offers fine levels of detail and focus—qualities that, in my experience, are hallmarks of well-executed single balanced armature designs.
Important note: for best bass response, try the following adjustment tip that Klipsch recommends. Insert the X10i’s (using the eartip size that best fits you), then gently rotate the headphone body (and eartip) left and right a few degrees and then slightly pull it backward just a bit. This technique helps the eartips flare out in your ear canal to achieve a comfortable, airtight seal—and with it, optimal bass response.
Unlike many of the headsets Playback has tested, the X10i (like the S4i) does not place its in-line microphone on either the left or right earpiece cable, but rather provides a 360 degree mic in a central position on the headphone yoke where the left and right earpiece cable join. This is a superior place to put the microphone and, as Klipsch points out (and I verified in my user tests), it means you don’t need to “talk down” into the mic. During test phone calls, call recipients reported that I sounded much more like myself with the X10i in use than when using my iPhone’s normal mic or other headsets I had tested in the past.
Above, I’ve alluded to the fact that the X10i’s single balanced-armature design gives it desirable qualities of focus and sonic purity. To hear those qualities in action, try listening to the Yo-Yo Ma performance of Massenet’s Méditation from Thaïs [The Essential Yo-Yo Ma, Sony]. Listen closely to Ma’s bowing changes and especially to his beautiful dynamic swells, and you’ll discover that the X10i gives you a vibrant, highly detailed and yet never cold or analytical–sounding presentation of the performance. Through the X10i’s, Ma’s cello sounds like a cello (not—as some earphones tend to make it sound—like a viola), with a rich, golden, woody tonality that’s full of energy and life. Capturing the warmth of music is one of the things the X10i does best.
The X10i also does a good job with bass instruments, as you can verify by putting on a tracks such as “The Lesson” or “Sifu” from bassist Victor Wooten’s Palmystery [Heads Up]. On either track, you’ll hear much (though perhaps not quite all) of the depth of Wooten’s electric bass and the even deeper “thwup” of occasional kick drum accents. But perhaps even more importantly, you’ll hear plenty of delicate mid- and upper-bass details, including the distinct, harmonically rich, “ringing” sound of Wooten’s round-wound bass guitar strings on sustained notes, plus the sure-handed intricacy of his fingering techniques. While a few competing in-ear phones (e.g., the Sennheiser IE 8 and Monster Turbine Pro Copper Editions) can go a bit lower and with greater authority, the X10i’s mid-bass articulacy is exemplary.
Finally, it is worthwhile to try a track that is rich in high frequency details and reverberant information to see what the X10i can do. A good example would be Imogen Heap’s “Bad Body Double” from Eclipse [RCA]. Imogen Heap’s voice is very closely mic’d on this track, and varying degrees of reverb and other processing tricks are selectively applied, giving the song a decidedly flamboyant, techno edge. Here, the X10i rewards the listener with excellent midrange detail, though it misses out on just a touch of the high-frequency reverberant information that can, under ideal circumstances, makes this track so special.
To give you a picture that shows how the X10i fits into the broader headphone market, I offer below, comparisons between the X10i and two competitors—one priced below and one priced above the X10. I include the Etymotic Research hf2 headset ($X179) and the Monster Cable Turbine Pro Copper Edition ($399).