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Audio-Technica ATH-CK90Pro

Audio-Technica ATH-CK90Pro Review

Audio-Technica ATH-CK90Pro
Reviewed Jul 2010

Details: Dual-driver monitors from Audio-Technica built around an acoustic horn design
MSRP: $299.99 (manufacturer’s page)
Current Price: $220 from
Specs: Driver: Dual Armature | Imp: 37 Ω | Sens: 111 dB | Freq: 20-15k Hz | Cable: 4′ L-plug
Nozzle Size: 4mm | Preferred tips: Monster tri-flange, Sony Hybrid
Wear Style: Straight down or over-the-ear

Accessories (3/5) – Single flange silicone tips (3 sizes), heat-activated foam tips (1 set), and soft carrying pouch
Build Quality (4/5) – Unlike the higher-end consumer-oriented CK10 and CK100, the CK90Pro features a no-frills plastic construction. The housings are sturdy though foam is used in the nozzle in place of a filter. The cable is nowhere near as thick as those of the CK10/CK100 and generally doesn’t feel very impressive for a $300 product. It lacks a cord cinch but is properly relieved on housing entry and terminated with the same iPhone-friendly 3.5mm L-plug as the CK100
Isolation (4/5) – The angled-nozzle design and thin housing allows for deep insertion and the sealed housing yields impressive isolation with the right tips
Microphonics (4/5) – The cable carries a bit of noise when the CK90Pro is worn cord-down but is general not very energetic and carries no noise when looped over-the-ear
Comfort (4/5) – The oddly shaped housings work surprisingly well when it comes to providing a comfortable fit. The earphones can be inserted quite deeply but remain comfortable. Over-the-ear wear takes a bit of getting used to as the housings need to be angled upward but becomes quite comfortable and very secure in the long run

Sound (8.7/10) – Being part of the Pro audio line, the CK90Pro is the black sheep of Audio-Technica’s high-end in-ear stable. Lauded on release as a CK10 replacement, it is hard to see how Audio-Technica ever intended to substitute the austere and impassive CK90Pro for the shiny and exciting CK10. But the CK90Pro has a place in Audio-Technica’s lineup even alongside the two consumer models. For one it is much darker-sounding than both – while the CK10 and CK100 are both somewhat bright, the CK90Pro is just shy of neutral, leaning slightly away from brightness. The CK90Pro also has the most impactful bass of the three, perhaps due to the acoustic horn setup of the sound channel. Its extension is very impressive, offering flatter bass than the CK100 and coming quite close to the linearity of the CK10 without as much of a sacrifice in low end quantity. Decay times are extremely short and the CK90Pro can nearly keep up with the speed and accuracy of the CK10 despite the greater slam. Still, the sacrifices typical of decay-less armature bass abound – there is simply no way the CK90Pro can keep up with the bass body/fullness of something like Panasonic HJE900 or Monster Turbine Pros even though they are plentifully impactful.

Expectedly there is no midrange bleed and, as with the CK10, the midrange is neither forward nor recessed. Clarity and detail are good but the CK90Pros are smooth to the point of sound ‘glossy’, meaning that there is a loss of microdetail as the earphones strive to avoid sounding sharp. The brightness present in the CK10s is nonexistent and harshness/sibilance are nearly imperceptible with the CK90Pro, with the side effect being a slightly duller sound, especially when it comes to female vocals. It is the treble, however, that draws me to Audio-Technica’s consumer-oriented earphones. Compared to the CK10, the treble of the CK90Pro is slightly de-emphasized and lacks the peaks that make the CK10 so bright and sparkly. It is clear and quite detailed but without that last bit of treble extension that makes the other two so effortless. Those who find the treble of the CK10 overbearing and are willing to sacrifice a bit of detail for a smoother overall sound may do well to check out the CK90Pro.

When it comes to presentation, the CK90Pro again impresses with excellent imaging and decent (though not nearly UM3X-good) instrumental separation in its average-sized stage. The earphones do have a good sense of space and do a surprisingly capable of job of not only left-to-right but also front-to-rear positioning. They aren’t pinpoint-accurate and not nearly as three-dimensional as something like the UM3X but do a good enough job of it to be involving without sounding unnatural.

But there is something else. The CK90Pro, being part of Audio-Technica’s Pro monitor line, is a proper studio monitor and something of a chameleon when it comes to source matching. Aside from the CK100, which requires careful source matching for different reasons, the CK90Pro may be the most source-dependent earphone I’ve tried. Hook it up to a Sansa Clip/Fuze and it showcases the strengths of the player with outstanding stereo separation and imaging. Swap those for a Sony DAP (A828 in my case) and they warm up and become even smoother. Hook them into an S:Flo2 and bass slam and note articulation improve noticeably. In addition, the old head-fi maxim of ‘garbage in – garbage out’ applies unequivocally in the case of the CK90Pro – feeding them low bitrate tracks out of a laptop’s headphone jack will result in an exceptionally dull listening experience.

Value (7.5/10) – The Audio-Technica CK90Pro may be the odd one out among the company’s high-end IEMs in design and build quality but its sound signature is just as polarizing as those of the CK10 and CK100. Dark and quite hard-hitting for an armature-based earphone, the CK90Pro is technically even more balanced than the others, boasting neither the forward midrange of the CK100 nor sparkly treble of the CK10. However, the sound of the CK90Pro has a strong tendency to reveal the strengths and weaknesses of its source and even the core signature won’t appeal to everyone. The CK90Pro, then, is business as usual for Audio-Technica. It is the proverbial love-it-or-hate-it earphone – those who enjoy a monitor-like approach to music will fall in love with its balance and technical proficiency; those who do not will quite possibly hate it.

Pros: Highly isolating and comfortable with the right tips, great technical proficiency
Cons: Build quality is disappointing next to other Audio-Technica earphones, strong source dependence, love-it-or-hate-it sound





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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