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Audio-Technica ATH-CK100

Reviewed Apr 2010


Details: Triple-driver flagship from Japanese audio firm Audio-Technica
Current Price: (discontinued) (MSRP: $649.99)
Specs: Driver: Triple BA | Imp: 23 Ω | Sens: 113 dB | Freq: 20-18k Hz | Cable: 4’ L-plug
Nozzle Size: 4mm | Preferred tips: Sony Hybrid, stock foamies
Wear Style: Over-the-ear or straight down

Accessories (3.5/5) – Silicone single-flange tips (3 sizes), heat-activated foam tips, and a soft magnetic-clasp carrying case
Build Quality (5/5) – The housings are made partially of Titanium and partially of thick plastic; an integrated strain relief protects the cables at the entry point. The thick and flexible cord (which is also used by the ATH-CK10) is internally braided for extra strength and is quite possibly the best in the industry. The well-relieved 3.5mm L-plug is shared with the lower-end ATH-CK90Pro
Isolation (4/5) – Sealed-back and very small, the CK100 gives a perfect seal every time and isolates very well with the foam tips and nearly as well with silicones
Microphonics (4.5/5) – Nonexistent when worn cord-up and barely noticeable when worn cord down
Comfort (5/5) – Small housings are designed to be worn cable-up but the offset stem means that they can be worn cord-down very easily as well. The small size and low weight make it easy to forget about them completely

Sound (9.2/10) – As a big fan of the older and wiser ATH-CK10, the CK100 has always had great appeal for me – appeal that was consistently counterbalanced by the $650 sticker price. When an opportunity to experience the CK100 for several weeks presented itself, I put all other reviews aside and began to prepare for the experience. I can say right up front that the CK100 is unlike any earphone or headphone I’ve ever heard. But let’s start at the beginning.

Initially everything is quite ordinary, with a subtle low end that gets bolder as the frequency counter approaches triple digits. Sub-bass is quite low on the CK100 – bass response definitely isn’t as linear as it is on either the CK10 or CK90Pro. Mid- and upper bass, however, is noticeably fuller on the CK100. Compared to the CK10 and CK90Pro, both of which have some of the shortest decay times of any IEMs I’ve tried, the bass of the CK100 actually carries more information. Still, the rumble commonly found in high-end dynamics is nearly nonexistent and the bass is very tight and fast. Naturally, there is no bass bleed. In fact, the CK100 are the only IEM I’ve tried so far in which the opposite is true – the lower midrange can overshadow upper bass.

This is counterintuitive for a reason – most headphones would need a gargantuan midrange boost to start drowning out the low end. The mids of the CK100 are indeed very forward, especially towards the top of the midrange. Listening to them side by side with the Ortofon e-Q7 makes the difference between mid-centric and mid-forward sound very obvious. The Ortofons are mid-centric – no part of their signature does anything to distract the listener from their midrange. The CK100s, on the other hand, do everything in their power to direct the listener to the midrange. Mids that are emphasized this much had better be good; and they are – with a single reservation – the CK100 has to like what it is plugged into (more on this later). The most striking property of the midrange of the CK100 is the extreme smoothness. Nearly as impressive is the transparency, which is partially responsible for the touchy nature of the earphones in terms of source pairing. Depending on the source, the mids of the CK100 can sound slightly cool or faintly warm. Towards the top of the midrange the emphasis reaches its peak without a trace of harshness or sibilance, resulting in a shiny but very controlled sound. Midrange detail is actually easier to discern with the CK100 than the CK10 due to the far greater midrange weight. Another effect of the peculiar balance is the low-volume prowess of the CK100 –only the Head-Direct RE252 can compete with them for minimal-volume listening enjoyment.

Moving on up into the treble, the CK100 maintains its incredible smoothness but due to the forward midrange, the treble seems less emphasized when compared to the ATH-CK10. Still, the CK100 can almost match the CK10 in extension and treble detail without sounding quite as bright or sparkly. Those who find the CK10 slightly sibilant should have no bones to pick with the CK100 – the shimmering and energetic treble is about as smooth as it gets without a sacrifice in quantity.

In terms of presentation the CK100 also holds its own quite easily against the best of the best. Though the soundstage is not the widest or deepest in absolute terms, instrumental separation, spatial positioning, and imaging are superb, especially in the midrange and treble. The forward nature of the mids results in a beautifully layered sound that works great with big band music and solo performances alike. Combined with the absolutely astonishing way in which the CK100 renders strings, woodwinds, and brass instruments this gives them an almost magical quality with string quartets and orchestral pieces. When vocals are present the CK100 always places them front and center. While this may not be to everyone’s liking, it really brings out more detail in vocals than I can hear even with my Heed-driven AKG K601, making them look like a great value compared to the $800 full-size rig.

Lastly, I want to discuss the one big caveat of the CK100 – the effect of source selection on that touchy and transparent midrange. When paired with a warm source, the mids of the CK100 are extremely sweet and actually somewhat relaxing. When paired with a source that is cold or neutral, the CK100 tends towards coolness and the quick-tempered midrange becomes a bit hard-edged, especially when it comes to female vocals. For this reason neither the Sansa players nor my iBasso D10 can elicit the full potential of the CK100. The S:Flo2 fares far better but buzzes very noticeably when paired with the CK100s. The buzzing is a problem with the player rather than the earphones but is annoying nonetheless. In order to kill the buzzing I had to run the S:Flo2 through an amp. The iBasso T4, though warm and very portable, actually detracts from the excellent resolution of the earphones. Ditto on my Music Valley RC-1. In the end, I settled on my aging DIY mini3, which is clearly overkill for the CK100 in terms of driving power but gives the desired tonality. If not for the tendency of the CK100 to reject otherwise decent sources for their tonal balance, I would have no problem declaring the CK100 the best sounding IEM I have heard; it certainly shows the most technical potential. But while it may be expected of high-end full-size cans, I consider this capriciousness of the CK100 a negative for an IEM and cannot put the CK100 a clear step above the other top-tiers.

Value (7.5/10) – Audio-Technica’s strict hold on distribution of their earphones makes the ATH-CK100 one of the world’s most expensive universals outside of Japan. Due to the inconsistent pricing, the touchy nature of the signature, and the fact that some people will love the forward mids and others will hate them, the value of the CK100 is extremely subjective. What isn’t subjective is the build quality, which is superior to any and all earphones I have held in my hands. Isolation, microphonics, and comfort are all far above average as well. As a total package the CK100 makes sense to me even with a $450 price tag. Just prepare to do some source tweaking to unleash their full potential.

Pros: Market-leading build quality, great comfort and isolation, addictively forward sound
Cons: Inconsistent pricing outside of Japan, love-it-or-hate-it midrange, picky with sources





Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


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