Astell&Kern AKT8iE In-Ear Monitor

Ace of Bass

Equipment report
Astell & Kern AKT8iE
Astell&Kern AKT8iE In-Ear Monitor

The most impressive aspect of the T8iE’s sonic performance was its cohesion. Not only did it speak with one voice throughout its frequency range, but it also produced one of the most cohesive soundfields I’ve experienced. It’s easy to understand the T8iE’s harmonic cohesion because of the single full-range driver and lack of any crossovers, but what about its spatial characteristics? Since I have no aspirations to design headphones I won’t speculate on why the T8iE’s imaging is so precise and dimensionally convincing, but I can confidently state that once you hear the way the T8iE places each instrument in space it’s hard to go back to a less three-dimensional headphone’s presentation.

I am among one of the least head-transfer-function-sensitive humans on earth [see sidebar]. Years ago Sony had a military-grade HTR calibration device at CES, which tested and dialed in your HTR settings. The device could never get the image to move all the way from the top of my head to the front. It got halfway there and stalled. But when I listened to the latest DTS-X demo through the T8iEs I was surprised to hear not only the front channels coming from in front of me, but also the front and rear height channels above me. On my own field recordings, most of which were made using the Ultimate Ears In-Ear Reference Monitors (IERM), the T8iE in-ears proved to be slightly more “real” in terms of their overall spatial rendition than the IERMs.

The T8iE’s second most impressive sonic characteristic was its bass response. I’ve never considered myself much of a “bass head,” so I wasn’t prepared for what I heard from the T8iEs. They have the deepest, most extended, most precisely detailed and controlled low bass I’ve heard from any in-ear monitor. This should not be confused with the sort of bloated “big” bass you’ll hear from some popular in-ears. Instead of “phat” bass the T8iEs generate true low bass. If you listen to EDM, techno, or modern pop, the T8iEs’ bass control will render what used to be low bass “stuff” into discernable parts and tracks. Unlike many headphones that are known for their “generous” bass response, the T8iEs’ bass rendition does not muck up its lower midrange response. The T8iEs’ upper bass and lower midrange resolution is just as articulate and detailed as the low bass.

Moving up to the midrange, you will be hard-pressed to find an in-ear monitor with a smoother, more even-handed presentation from the lower midrange up through lower treble. This even-handedness extends to the way the T8iE handles musical details. For example, the rhythm guitar’s flutter (as in tape wow and flutter) and the muffled piano in the left channel on James Taylor’s “Sweet Baby James,” from the same-named album sourced from the 96/24 AIFF from HDtracks, were quite obvious through the T8iE. On older recordings you will hear all the warts along with getting closer to the sound than you thought possible. Just as great singers have, seemingly, all the time in the world to finish a phrase while luxuriating in a song, the T8iEs’ give your ear-brain ample time to examine the music’s inner fabric.

The T8iEs’ upper-mid and treble regions were as smooth and resolving as its midrange. The leading edges of the string section, especially the first violins on my own live concert recordings, had just the right amount of sheen and sparkle. The treble (up to 14kHz, which is where my hearing ceases) was airy and incisive and I never felt any desire to turn up the treble or add additional treble energy with eq. In comparison to the AudioQuest Nighthawk headphones, which also have excellent bass extension, the T8iEs’ don’t sound as dark or hooded on their top octave.

The T8iEs also do an impressive job on dynamics, both micro and macro. Take that old/new audiophile demo workhorse Daft Punk’s “Get Lucky” from an 88.2/24 version of Random Access Memories from HDtracks. The bass is big and plumbs the depths but is never slow or turgid. The multiple synthesizer lines each have their own individual dynamic emphasis, and the T8iEs preserve all of them. On modern pop the T8iEs excel, keeping the rhythmic drive pulsing while retaining the subtle dynamic interplay between parts.

If forced to come up with a performance area where the T8iE is less than state-of-the-art I would point to the size of its soundstage. Several other in-ear monitors I’ve used generate a soundfield that is larger and that seems to extend outside your head, including the Westone ES-5 and the Jerry Harvey Layla. On my own personal list of negatives this is a relatively minor shortcoming, but one that experienced headphone users will notice almost immediately.

Any in-ear priced at just under $1000 is bound to have some stiff competition. In this price range you will find custom in-ears including the Ultimate Ears UE Pro Remastered ($999), which is a revision of the Ultimate Ears In-Ear Reference Monitor. When it comes to fit, the UE Pro Remastered wins easily. The UE Pro also has better isolation with a -25dB published specification. Sonically the T8iE has more low bass extension and more dynamic contrast, but it’s a dead heat in terms of imaging and low-level detail.

The Westone W-60 is also priced at $999, and also is a universal-fit in-ear monitor (but you can add custom tips). With six balanced drivers and three crossovers per side, the W-60 has a radically different design than the T8iEs. Both fit equally well with multiple fit options. The W-60 has a larger soundstage that rivals many full-sized open-ear headphones, but it lacks some of the T8iE’s dimensionality and directional specificity.

The Astell&Kern AKT8iE’s most outstanding sonic attribute is undoubtedly its wonderful bass, which will appeal to both EDM fans as well as any classical listener into pipe organs. The T8iEs go deep, cleanly without bloat, and they do it with dynamic acuity. After its killer bass the AKT8iE’s second outstanding sonic trait is its cohesive, three-dimensional, and exceedingly specific soundstage. While not the biggest soundstage, the T8iE’s level of dimensional precision is exemplary.

If you’re considering a $1000 universal in-ear monitor, obviously you’re pretty darned serious about portable audio and you have well-developed tastes. The Astell&Kern AKT8iEs were created for people just like you. Once you overcome the principal weakness of any universal-fit in-ear, which is obtaining optimal fit, the T8iEs perform on a level that closely approaches the best I’ve heard from any headphone technology, including custom in-ears and full-sized reference headphones.


Transducer type: Dynamic
Operating principle: Closed
Frequency response: 8Hz–48kHz
Impedance: 16 ohms
Total Harmonic Distortion (THD): <0.2%
Power handling: 10mW
Dimensions: Not specified by manufacturer
Weight: 0.3 oz. without cable
Price: $999

39 Peters Canyon Rd.
Irvine, CA 92606

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