I really like the Klipsch Reference X6i in-ear headphone ($179, £124, AU$269), first because it's unusually comfortable, thanks to its ultra-light weight (0.6 ounce/18 grams), and small size. Then, as I listened while wandering through the Museum of Modern Art the X6i provided a perfect soundtrack for looking at art. Isolation from external noise was above par, and the sheer clarity of the sound was exceptional. The die-cast zinc earpieces and robust headphone cable bode well for the X6i's long-term reliability.
Looking over the specifications for the X6i, one thing jumped out: the headphone has just a single balanced armature (BA) driver in each earpiece. That surprised me because most single-driver BA in-ears sound too lean; the X6i is full-bodied and rich. All of the much more expensive in-ear designs from Jerry Harvey Audio, Westone and Ultimate Ears use two, three, or more BA drivers per earpiece to fill out the sound, but the X6i does a great job with the single driver.
You get four sizes of Klipsch's patented oval silicone ear tips with the X6i. I used the biggest tips, and they really did produce a much better than average seal, all the better to hush external noise. The X6i features an iPod/ iPad/iPhone compatible three-button remote and microphone, the cable is fitted with a 3.5mm plug. The X6i's impedance is rated at 50 ohms, and I found this headphone to be unusually sensitive (110 dB/1mw), so it can play louder than most in-ears do with portable devices.
The X6i is available in black or white finishes; accessories include a nicely designed flat carry case, and a shirt clip for the cable. Warranty runs one year.
The X6i's sound clicked with every music genre I tried: rock, hip hop, dance, jazz and classical. Even harsh and grating recordings like both Alabama Shakes albums were enjoyable over the X6i, which is great because I love the band's energy.
Clarity was first-rate on Amanda Palmer's "Performs the Popular Hits of Radiohead on Her Magical Ukulele" album, every strum and pluck was distinct, and her vocals were heartfelt. The X6i was always exceptionally neutral; that was its standout feature as far as the sound goes.
Comparing the X6i with one of my recent favorite in-ears, the 1More Triple Driver, the differences were immediately clear. The X6i has a sweeter, more refined treble, and more open, less stuck-inside-my-head stereo imaging. The Triple Driver sounded smaller and dynamically limited next to the freewheeling X6i. Bass was pretty terrific on both headphones, but the X6i's was more nuanced and detailed.
The Klipsch Reference X6i has a lot going for it, starting with comfort and build quality that are first-rate for the money, and the sound is superb. The X6i is an audiophile-grade headphone selling for an affordable price.