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[Review] CK100PRO Unboxing & Impressions (+ a retrospective journey with Audio-technica and versus CK100)

post #1 of 355
Thread Starter 

Official TVCM (song featured is BoA's Milestone single)
Official TVCM Making of/Behind the Scenes
Japanese TVCM Flash site: View here
Special Feature: View here
Product Specs: View here

Product Specifications:
  • Driver Technology: 3-way, 3-driver Balanced-armature Design
  • SPL sensitivity: 109dB/mW
  • Frequency range: 20Hz ~ 18kHz
  • Impedance rating: 39ohm
  • Weight: around 9 grams
  • Cable Length: 1.2 metre (Y-split cord design, detachable option)

Hello everyone! as promised earlier in one of the discussion threads started by fellow Head-fi member Randius (who's also a fellow countrymate from Singapore), I will be doing an unboxing + impressions review of the CK100PRO. My pair has arrived since late last week, but because I have been busy with couple of stuffs plus spending some late nights with TES 5 Skyrim (an excellent RPG made by Bethesda Softworks as I have always been a longtime fan of their TES series) thus this review was kinda delayed on my part.

Before I start off, please kindly take note as I'm not a professional reviewer nor do I have a good flair for writing these sort of technical IEM reviews like how |Joker| or james444 usually does around here, they may not be as descriptive as you may like or expect. My listening impressions will also probably vary abit with other people around here who may also own the same IEM models as me, and they are of course subjective due to my personal inclinations/preferences/experiences mostly with IEMs that are usually mid-centric or treble-heavy in nature, as I usually avoid purchasing warm/bass-centric phones in real life.

But because I want my review to be balanced as well, I will be trying my best to be as unbiased & professional as I can, in describing the pros/cons of both the CK100PRO and CK100 models respectively. As usual with all other online reviews found on the net, please take my subjective opinions with a pinch of salt as what they always say, your ears will always be the best candidate for making a more informed/better judgement when it comes to selecting IEMs or headphones for yourself. I also welcome all other CK100PRO owners on this thread to discuss and share your own personal findings or opinions, or any potential to-be buyers of this latest IEM product produced by Audio-technica. smily_headphones1.gif

Box Packaging:


In terms of the box size compared to the CK100's, it's comparatively much larger/bigger in size. According to my japanese friend who has already listened to these and the CKM1000, it seems that only the CK100PRO/CK90PRO MKII models are made in Japan, while the CKM1000s were made in China. Don't have any idea regarding where the CKW1000ANV were made though, may have to wait for local distributor sets to turn up to find out for yourselves.


The english description on the actual product box reads "Detailed high frequencies, balanced midrange and powerful bass." Is Audio-technica lying to us for pure marketing purposes or there's indeed some truth to these claims? Well you will find out more in my review later.


Frankly, just like most previously released Audio-technica IEM products (or to a certain extent as with most japanese manufactuer produced IEMs like Final Audio Design/Ortofon), you don't get very much optional accessories other than the basics. (probably a huge disappointment to some people especially coming from UE/Shure/Westone products)
Below is a clear summary of what comes originally bundled with the CK100PRO for its given accessories.

Bundled Accessories:
  • Supplied original detachable cables
  • ER-CKM55 original silicone eartips (in size S, M, L)
  • Comply™ original foam eartips (size M, T-200 model)
  • Leather carrying pouch w/square-shaped plastic earphone holster (unfortunately, the material is made up of vinyl faux leather instead of real leather as found on the former CK100, probably for cost cutting reasons especially after their 3/11 fiasco for Tohoku Japan)

Size Comparison:


Here are some pictures to show you guys the difference in the housing shell shape/size against the CK100. You can see that the titanium shell is now considerably abit larger than CK100, so people with very small ear canal shapes may have some problems here though as usual, your mileage may vary.

Cabling material is exactly the same as with my CK9/CK100, very soft and supple with no memory wire effect. It has a L-shape angled minijack similarly like the one on CK100, the third picture is sorted in chronological order from latest purchase to oldest purchase. (CK100PRO, CK100 and CK9, by left to right sequence)
post #2 of 355
Thread Starter 
The Fantastic Fours:


ATH-CK9 (discontinued product):
  • Product Page: http://www.audio-technica.co.jp/products/hp/ath-ck9.html
  • FR Data: http://en.goldenears.net/GR_Earphones/5536
  • Purchased: June 2008
  • Damage: around 200SGD (based on japanese SRP)
  • Where to buy: As it's officially discontinued by AT, most likely you won't be able to find these through any authorised retailers anymore. Ebay or Yahoo Japan Auctions might be a solution, but please
    be aware that both Audio-technica and Sennheisers are usually fav brands for China manufacturer replicas, so unless they come with proper packaging or warranty card I wouldn't take any of those risks.


Also known as Audio-technica's first Balanced-Armature IEM to ever grace the market. If I'm not wrong this IEM product was released as part of their 45th year anniversary commemoration if I recall correctly. It was also my first BA IEM,
as before purchasing the CK9 I had only owned dynamic IEMs so far, so you can say it was truly an eye-opener in terms of the high resolution/clarity of the typical properties of the balanced-armature driver technology.

Short Notes:

There's nothing much to describe about this single-BA IEM since I believe the balanced-armature technology has advanced forward so much since the older days that nowadays there are probably alot of cheaper and better single-BA IEMs out there for a very reasonable pricing.
However as these were my first pair of BA IEMs and I quite liked their sound signature (after they were burnt in and the sound opened up, kindly see below for further clarification), these do have a very special sentimental value to me that IMO is very hard to be replaced by other single-BA IEMs out there.

If I were to describe its overall sound signature, this would probably sound very close to the Phonak PFE v1s or Etymotic HF5 with quite abit of tight bass punch/impact though it probably won't satisfy any bassheads out there. It has this kind of lean and dry sound signature with a good and clean top-end which may be considered to be too clinical for some people's listening tastes. They are mid-forward just like most AT's out there, but their overall presentation is not as mid-centric/heavily coloured as CK100, rather I find that these share more similarities with the CK10/CK100PRO brethens.

These got pretty much used and abused by me for the past three years, but nowadays I don't exactly use them anymore now for my portable rig, only occasionally using them for sleeping. Despite what some people out there are saying about their fit these can be quite comfortable in terms of fitting actually just like most Shures/Westones IEMs out there due to its angled-nozzled design and how the whole housing tends to fit nicely in your ear.

The CK9 also requires quite a large amount of time and patience to experience the improvements of burning-in effect compared to my other IEMs so far, as the midrange didn't really opened up to produce AT's airy and lush signature until sometime after the 300-hours plus mark.
Before the burn-in effect kicked in, they sounded really dry and overly harsh/sibilant which did not sound very musical right out of the box, but if you are patient enough with them your hard work will certainly pay off as personally I even consider this IEM's midrange/mid-tones quality to be much better and slightly ahead of the CK10's, even though both of them overall does share the same kind of treble signature, as well as the similar treble peaks/emphasis in the upper-mids region.

Robust cabling material/design similarly as my CK100/CK100PRO with no memory wire.
Able to easily provide a much deeper, ease of seal and isolation factor compared to my other more expensive IEMs to date.

Plastic housing with average build quality. L/R markings and painted-on manufacturer logos tends to fade easily over time as compared to the engraved/etched ones on my CK100/CM700Ti. (for example, the left channel L-markings and manufacturer logo on my pair has already faded off completely)

ATH-CM700Ti (Titanium ver, discontinued product):


The CM700Ti is the little brethen and replacement successor of the CM7Ti released back in 2003, a set of quality earbuds clad in titanium housing that has garnered quite alot of loyal supporters and fans in JP several years ago.

The CM700Ti came into the picture around two years back when I was looking around for a quality earbuds and after doing my homework online it was down between the Sony MDR-E888, Yuin PK2s and the Audio-technica CM700. I have tested/listened to all 3 myself, in my own words the MDR-E888's lower-end frequency was kinda too bloated and much for my own liking and its overall resolution/clarity was only slightly ahead of my E931, the Yuin PK2 while has a treble that's pretty warm and smooth to my liking, was actually lacking the clarity/analytical factor I was yearning for.

ATH-CM700 was my final choice in the end, but back then I found out here in Singapore it's near impossible to get the Titanium version (AT sold this locally in both BK/SV color variants made with Aluminium housings, while there's also another more pricier version clad in Titanium housing aka Ti version and is also made in Japan *both the BK/SV versions were made in China instead) Thus decided to request my japanese friend
for help and through some mere stroke of luck managed to found a BNIB set on Yahoo Japan Auctions for me after much patience and scouring. Back then the highly-acclaimed Yuin PK1s were retailing for close to 240SGD, and because Yuins are generally known to be pretty weak in build quality and also has a rather high impedance and needs an amp to sound good so I didn't want to take the risk so IMO this is still considered a pretty good bargain considering the CM700Tis were already been discontinued in JP.

I did also take into consideration the more extinct and discontinued CM7Ti's, but after doing my own research online, I found out that the CM7Ti while being more heavily colored in terms of sound presentation and also highly regarded by many HK/Taiwan audiophiles as being an excellent choice for female vocals, are only quite suitable for listening to female vocals strictly only that's all according to many chinese threads. I wasn't looking for a female vocals-oriented earbud since I already had my CK9 back then, and furthermore since the CM7Ti also only comes in 0.5m cable length configuration with provided 1m cable extension, as well as having a J-shaped asymmetrical cord design which I have always hated, so it was a no-go for me thus I chose to purchase CM700Ti in the end.

Short Notes:

These actually have a pretty clean and balanced signature without sounding overly harsh/sibilant to my ears. When comparing the CM700Ti to my first AT IEM which is the CK9, it's pretty obvious to my ears the latter has a slightly higher resolution/clarity and quicker transient response to it, but to me the CM700Ti's displayed an exceptional strength in terms of dynamics, and a much vibrant and roundness in their mid-tones quality and some pretty decent bass quality/decay (though not so in terms of quantity) over my previous single-BA CK9 so to this pair of ears it's of no mistake that I actually preferred the CM700Ti over CK9 when it comes down to sound quality strictly.

It was also for the first time I finally realised that you can actually get this level of dynamic range and soundstage quality from just a pair of small portable earbuds, and one that can actually match similarly to some of the mid-fi full-sized cans out there. As someone who have placed alot of faith in terms of balanced-armature technology after acquiring my first BA IEM, honestly this wasn't quite something I was expecting as back in those days normally single balanced-armature IEMs were all the rage as with Etymotics ER4P, Shure E3Cs, Westone UM1 and of course the ATH-CK9s themselves being the popular selection choices among many audiophiles out there.

I would also like to add on that, despite there is a perceived higher level of brightness/transparency in the Titanium version over the normal BK/SV aluminium editions to my ears, I usually wear these without any foam pads on as it's much more to my sonic preference liking. (but I cannot walk around much without the foam pads on, as the earbuds will easily drop off due to their housing weight, so I only use them when I'm sitting down, or standing in a static position and not moving around)

The CM700Ti like it's earlier sibling CM7Ti and newer sibling CM707 are all based on an open-vented design, so isolation isn't exactly the best nor can it be compared to my previous CK9s or any decent in-ear monitors found these days for that matter.
As these do leak quite abit of sound just like many open-design phones out there such as my Grado RS-1i/Sony MDR-EX800ST, I don't exactly use them outside anymore now in terms for my portable rig, instead they have been relegated to use only at home on my Onkyo CD transport or PC desktop occasionally.

These earbuds do experience a great amount of improvement changes between burning-in periods, as I had personally experienced sound changes between the first 50-hours, and after the 150-hours mark.

It has a titanium-clad housing and stem design which are considered to be pretty indestructible, I consider the housing build quality for these to be one of the best/polished in terms for consumer grade earbuds (the housing finishing for these are even slightly ahead of CK100/CK100PRO IMHO), and definitely puts the Made in China Yuins to shame.

In terms of sound this one has definitely enough level of clarity/details without the whole sibilance issues that plagued my previous CK9 to satisfy any detail freak out there. IMO this is considered one of the best earbuds you can buy for your money according to one of the major review comparison written sometime ago on Head-fi. (contributed by Kostalex and many others on that thread so credits all goes to them)

While this has a rather robust housing finishing/build the funny thing is it also has probably one of the worst cabling materials/Y-split design you can ever find on an AT product, and is a stark contrast compared to the CK9, CK100 and CK100PRO's reknowned cable build quality.

I can foresee the cable wiring/mini-plug to fail me sometime in the near future and that's when I will probably look for a modder to make/reterminate a custom cable for this when it happens. I'm currently using a 3.5mm to 1/4" stereo-jack adapter in order not to put the strain on its miserably small straight mini-plug.

Without proper equalization, it is also considered bass anemic even by my own standards and I'm not even a basshead myself, but things can be improved to an extent with some helpful EQ-ing in this case. While Classical and acoustic jazz genres sounds pretty fine with this out of the box with no EQ-ing done, others like hard rock or electronica/trance genres tends to suffer abit when there's no equalization applied.



This was my first pair of triple-BA IEMs. After coming across them sometime back in late 2009 in JP and listening to a pair of well-burned in set, slightly more than a year later I finally lost my control of lust for it and the rest were history.Since I will be providing an A/B comparison between the CK100 and CK100PRO in my second part of the review, I will attempt to describe both of these IEMs' own unique signature and sound characteristics more in actual detail in the following paragraphs.

Build Quality:

Comes with a nicely designed half-titanium/half-plastic housing shell with engraved logos and L/R markings. Definitely one of the smallest housing design ever for a universal triple-BA model. (kindly refer to this picture for some comparison in size with the TripleFi 10)

It features a very robust cabling material/stress relief design near the housing which is comprised of very hard rubber material with a soft and flexible cabling material on the cables itself with no memory wire. The CK100 will always be my reference standard in terms of build quality whenever choosing a universal IEM for myself.

Sound Signature/Resolution:

In terms of clarity/resolution, to my ears the CK100 doesn't exactly sound quite as analytical or bright as what the CK9/CK100PRO family siblings does. Instead it has this rather liquid and pleasing mid-centric sound that is quite airy/transparent and yet at the same time is also very resolving and detailed in the highs, without giving the listener any sort of listening fatigue. (by comparison between similarly priced 3-driver BA IEMs for example, IMO I have always thought the CK100s were much more controlled/refined in the highs region when compared to phones such as the normal edition Shure SE535s or the UE TripleFi 10s)

Detail Retrieval is moderately good. Vocals sounds exceptionally clean and well-refined. It has the ability to let you hear the backing instrument nuances going on in vocal tracks, and because the CK100 actually place a larger emphasis in their midrange vocals are also usually more pronounced and forward-sounding, in my experience even more so than my CK9/CK100PRO.

However, there's a caveat point that I would like to highlight though. In terms of extended treble extension and picking up micro-details in the background in a music track I would say the CK100PRO are probably slightly ahead/more obvious than CK100, the reason I believed being caused by its intended tuning or taming done by AT in the upper-mids region. There's a slight bit of perceived smearing/veil of details and focus due to a gradual roll-off in the upper-mids region around the 2kHz - 7.5kHz spectrum range due to its intended coloration I believe. My personal listening experience also seemed to concide with the frequency response data taken from Sonove's blog, please kindly refer to the above-mentioned FR graph data tagged above to understand more regarding this issue. (for more reference, refer to audio glossary "haze, haziness")

Sound Texture/Tonal Balance:

The treble texture of the CK100's can be considered to be very smoothing and creamy (IMO it shares some similarities with some other universal IEMs such as Sennheiser IE8 or Earsonics SM3 v2 in terms of texture characteristics). Vocals are usually accompanied with this non-fatiguing, delicately sweet and silky texture without sounding overly harsh/aggressive to my ears. (for more reference, refer to audio glossary "golden", "liquid" and "sweet")

On the contrary, the CK9/CK100PRO models are quite the opposite of this characteristic traits, as the latter two are considered to be much more leaner/brighter and more revealing on many vocal tracks that I'm familiar with, mostly due to the treble peaks occuring in their upper-mids region in their frequency response and thus having an overall much leaner and clinical signature. (to some people this may actually be quite fatiguing to listen to for long hours, so IMO this was something that the CK100 had an advantage over the CK9/CK100PRO)

There's a good amount of treble details and extension here but in all honesty, these traits are considered to be much more articulated/pronounced on the CK100PRO to my ears, but despite that the CK100 doesn't have the same level of texture articulation or micro-detail retrieval that the CK100PRO has, at least it doesn't suffer the issues that plagues the CK100PRO especially with those upper-mid treble peaks which may prove to be a glaring problem for some people's listening taste/preference. (though in my own words, in CK100PRO's scenario there's always some Comply foam tips or EQ-ing software to rectify these issues)

In terms of tonal balance, there is this huge emphasis placed on its midrange region usually due to its mid-forwardness projection and coloured "slightly warm and creamy" mid-tones quality, so it will always demand and divert the listener's concentration and focus towards it. This can be said to be a good or bad thing, in my opinion if your portable source does not display a good synergy with it well, it will definitely sound
just plain wrong or unmusical to your ears. This is because I have found out from a small experiment conducted awhile back, through testing with a friend who owns both Cowon S9 and J3 DAPs and found out for myself that the Cowon's signature sound did not seemed to bode that well with the CK100 actually, as to my ears the sound signature became much drier (the mid-tones quality became even much colder and sterile) and just sounds much less musical to me despite having a much cleaner and transparent top-end compared to the sound output I was originally getting from my own NW-HD5 Sony Walkman.

According to some previous thread discussions on Head-fi as well as other japanese BBS discussions that I had came across, it is reported that the NW-HD and A/X-series Walkman DAPs by Sony normally have this distinctive thickness and warmth signature characteristics to them, in contrast compared to the Cowon players I had tried which sounds much colder and drier sounding with their main signature which probably explains that the Cowons may have a certain synergy issue with the CK100s. Of course these are all pretty subjective based on my own listening. If there are any Cowon owners around here holding onto a pair of CK100's as well please kindly feel free to comment on this issue in your own words, as I will be interested to know more about this too so more inputs are always welcomed.

In terms of bass response, the bottom end has a moderately good pitch definition with a good amount of decay. I can't really explain whether these have a neutral or accurate bass response, because I'm not exactly a basshead myself and have also noticed in almost all modern universal IEMs produced by various manufacturers these days, with the exception of Etymotic ER4 usually most IEMs' bass response can be quite colored and tailored to suit mainstream contemporary music out there. In my own words unless you are using monitor headphones such as my pair of CD900STs, you are very unlikely to get neutral or accurate bass response despite having a good source.

Despite all that being said, I do quite like the CK100's bass quality as they are pretty punchy and quick with the right amount of decay timing and body presence for common percussion instruments like snare/kick drums, and do not seem to over-emphasize the mid-bass region that plagues some of the triple-BA IEMs out there such as the TripleFi 10. (by the way have I mentioned how much I hate the TF10s? lol) However, because of their slight roll-off nature in terms of bass extension and the almost grain-free/lean nature in terms of bass notes they are considered slightly more diffuse and also lacked abit of articulation in terms of bass details when compared to the newer CK100PRO, so in my most honest words they may not exactly be the best universal IEM for listening to male vocalists with chesty vocals or any of those trance/electronica genres requiring a good amount of bass energy and details, although this can also be subjective to certain people and YMMV of course.

Dynamics/Transient Response:

The CK100's has a pretty well-refined dynamic range, attack and decay attributes, it is able to easily give the listener a good sense of power and presence and balancing factors like speed, dynamics, decay during a track. IMO these factors are quite important in order to convey the hit impact, resonance or decay of many of the common brass/strings/percussion instruments going on in a classical/orchestral track.

Ride cymbals shines through as bright and lively while trombones/horns resonants off the air with that well-refined and clean ringing in a non-offensive/non-fatiguing way. Whether it's listening to either slow-paced ballads or vocal jazz tunes it can display an exceptional romantic and delicately sweet presence, yet at the same time can also present with an edgy and aggressive signature whenever the recording calls for in various different situations. They can also easily cope with busy or complex passages without becoming muddy with no sweat.

Whenever I'm listening to either Olivia Ong's gentle vocals or Asian Kung-Fu Generation's fast drumming or guitar picking skills the CK100 manage to handle them with ease and definitely a real treat to listen with. I would consider the above-mentioned traits as the CK100's main advantages over my other IEMs I have owned so far before the CK100PRO came into the picture, as both dynamics and speed are definitely the CK100's strongest forte and best feature sets.


Vocals/Instruments can be clearly defined, and easy to distinguish apart. Vocalists are usually center-filled and projected quite mid-forward (so instead of a couple of rows away from the stage just like watching a real concert performance in an actual theatre hall, their sound presentation will always place the listener right on the stage together with the singing performers/backing instruments, in this sense it shares very similar traits here with my RS-1i headphones and to a certain extent, the CK100PRO as well).

The backing instruments does take a slight backstage here with the main vocals feeling more pronounced/forward usually, but it is still pretty easy to pin-point each of their various respective positions without sounding too blended together. The CK100 gives a good sense of aliveness and 3-dimensional spatial realism of acoustical space/ambience between the singing performers and the instruments going on in the background in the music track, which makes you feel like you are actually watching an actual live performance or being placed in a real live concert theatre hall with the actual performers. (for more reference, refer to audio glossary "realism" and "acoustical space")

The soundstage has a 3D-like presentation that surrounds the listener and are reasonably wide with decent depth to my ears. It is well-layered and has a good sense of depth, air and space though it is still considered those in-your-head kind of headstage presentation, unlike some of my other portable in-ears such as the EX800ST/CM700Ti as the latter two dynamics definitely sounded much more expansive/natural to me without that in-your-head effect, but to my basic understanding this is simply a mere technical difference btw a vented open-design and closed-design so this is quite understandable.


Able to provide a relatively ease of insertion and seal when wearing, and can be easily worn either over-the-ears or straight down. (a huge improvement over my previous CK9)
For increasing seal/isolation for CK100's case, I do recommend using Monster/Shure's tri-flange tips or the default ER-CK100 foam tips provided by AT out of the box which are made of similar material as Shure's Olives, or Comply™ T-200/TX-200 foam tips.

Easily excels with the kind of genres consisting of contemporary asian female vocals and ACG music (ACG is a short abbreviation for Animation, Comics & Games)

Well-knowned music composers/artists such as Nobuo Uematsu, Yasunori Mitsuda, Yoko Kanno, Masumi Itou, Maaya Sakamoto, Nana Mizuki, Aya Hirano etc will naturally comes to those fans mind when referring to this kind of music genre.

No doubt a very good universal IEM to listen to most asian female vocalists and IMO possess an exceptional and unparalleled quality when it comes to portraying piano or any of the most common form of string instruments such as guitar or violins. For example, there's this perceived glossy/honky coloration applied when listening to music tracks containing solo piano pieces. Although this sound characteristic can also be perceived as having superficial/unnatural sonic qualities to some people, to this pair of ears they are truly a very nice and pleasant experience that none of my other portable IEMs has managed to offer me so far.

Not exactly the best IEM to listen to some electro-pop artists such as capsule, Perfume etc or most electronica/trance genre of music from my own experience. Earlier models such as CK9, CK10 and the latest CK100PRO actually tends to excel much better at portraying these kind of music genres, as IMO the CK100 does lack the required top-end sparkle/articulation in texture note details to make this form of music enjoyable.

Also CK100's bass extension doesn't exactly extend down that low (the CK10/CK100PRO models can actually go down much lower from my own listening experience in terms of the sub-bass regions/lower fundamentals) and neither does the bass note timbre sound thick or full-bodied enough like most other well-known top tier Shure/Westone IEMs, so these may not exactly be the best IEM choice to own especially if you are a huge fan of most contemporary UK/US male artists. (despite how much I love the CK100's, this is one of their main weakness that I must personally admit)

It's midrange coloration may also sound be considered too "cold or unnatural" for some people's listening tastes especially if you match it with a wrong source or amp.

However I do want to highlight one point, that is although CK100 may not seemed that enjoyable when listening to most US/UK contemporary male artists due to the above-mentioned deficiencies, IMHO it can still portray an exceptional and unique sound personality that may prove to be enjoyable to some people when listening to some male artists out there with androgynous vocals (for example in my own case, in the West I have always enjoyed using the CK100 to listen to artists such as Michael Jackson and Savage Garden's lead vocalist Darren Hayes, and in the East with asian music artists such as Hideki Tokunaga, Ken Hirai, Jeff Chang)

  • Product Page: http://www.audio-technica.co.jp/products/hp/ath-ck100pro.html
  • FR Data: none found so far. (will update later when it's available)
  • Purchased Date: November 2011
  • Damage: around 850SGD (based on japanese SRP)
  • Where to buy: (based on my personal recommendations which are reliable)
    Amazon Japan


This is Audio-technica's latest triple-BA IEM product that were just released in Japan on the November 18th last month, and is considered their current highest-end BA flagship model in terms for their line of IEM family. According to its AT's official product press page and some of the earlier japanese coverages written by the editors of AV Watch Impress, the fundamental improvements made
to this model includes a 3-way passive crossover implementation (as compared to 2-way crossover implementation in the CK100, 1 to the lower-end frequency and 1 to its mids/highs frequency), the Acoustic Horn patented technology (which was also utilised in the latest CK90PROMKII as well as former CK90PRO and CK70PRO models) for its nozzle for reducing sound resonance and lastly, also made use of a larger woofer BA driver compared to its previous balanced-armature IEM models.
For its detachable cable design, AT has opted for the MMCX-style connectors similar as those found on Shure IEMs, but because the pin design is reversed on the CK100PRO, it's pretty obvious to me you can't use the original Shures or any of those 3rd-party cables made for Shure IEMs.

Build Quality:

The CK100PRO again comes clad in a sturdy half-titanium/half-plastic housing shell that exludes a certain class and elegance feel. It is based on a slightly more symmetrical design compared to the CK100, as the titanium shell now fully covers the main housing, only the inner-portion closest to the nozzle part and the nozzle itself is comprised of plastic material.

Unfortunately this time there's no engraved or laser-etched logos and L/R markings that was found on the CK100, instead it's just color-painted on the plastic portion near the nozzle part. The original included detachable cable does come with nicely laser-engraved and color-coded L/R markings (blue for left channel and red for right channel) to highlight the proper way for the wires to fit the right channel, and similarly as CK100 it's cabling material/stress relief design near the housing is comprised of very hard rubber material with a soft and flexible cabling material on the cables itself with no memory wire.

Overall the build quality is very close to CK100's standard so there's nothing much to complain here.

Sound Signature/Resolution:

These seemed to portray a much more lively sound showcasing quite abit more treble energy compared to the CK100. IMO these phones probably share a much closer relationship to its younger siblings under the same family such as the CK9/CK10 models, instead of the CK100 in terms of overall sound signature. From the back of my head since I have heard most of AT's phones, these sounds kind of like a mixture between CK9/CK10 and also has some of the characteristic traits found in AT's full-sized A2000X headphones.

They are also very much more detailed and revealing than all my previous IEMs so far, I can easily hear those imperfections and nuances/micro-details going on in the background in many recordings that I don't usually notice with my previous CK9/CK100. The detailed and revealing nature of these also reminds me alittle bit of the MDR-CD900ST/EX800ST by Sony, which I currently own as well. IMO this can be both a blessing or a curse, while with excellent mastered classical/orchestral recordings I can truly appreciate and enjoy all of the details I am hearing in the music, but at the same time it has also proven to be quite unforgiving when listening to certain poorly-recorded mainstream music.

In these scenarios perhaps using lossless formats such as FLAC/ALAC may help improve matters here, but I believe it is still largely depends on the quality of the original CD's recording/mastering IMHO. (for my own NW-HD5 Sony Walkman, I only use 320kbps encoded MP3s or 352kbps encoded ATRAC3plus formats for my own music collection)

Detail retrieval is exceptionally good, to my ears these are actually a few notches above that of the CK100 and coming very close to my very revealing MDR-CD900ST which is a "reference grade class quality" headphones meant more for monitoring purposes. The CK100PRO has the same kind of analytical/crisp-sounding signature similarly as my MDR-CD900ST/EX800ST phones, but yet at the same time also sounds very musical to my ears and not overly clinical like the CK9/CK10 models.

In terms of overall sound presentation I do think they are much flatter and quite similar to the CK9/CK10 models, the midrange region also has noticeably less of that resonance effect when it comes to portraying certain instruments and sounds less coloured than my CK100, while in terms of the top-end response it has a well-extended treble with a good bit of sparkle/shimmmer thrown in without sounding overly harsh to my ears. I think it's correct to say its treble extension is a few degree notches above CK100, as it seemed to extend further away really well when listening to some of my soundtrack collections, for example in one of Hans Zimmer's Inception OST track "Dream is Collapsing", the trombones and french horns comes off as having a much more powerful liveliness and presence to it.

Sound Texture/Tonal Balance:

To be honest, I think this may be considered the biggest surprise so far with the CK100PRO after listening to so many previous IEMs produced by Audio-technica personally. While these still have a unique character that's strongly associated to some AT phones I have heard before, they don't exactly have a heavy coloration to themselves. In my own words these don't exactly add alot of extra "preservatives" on-top of your music, it sounds quite neutral and balanced to me. Although I can still hear sparkle/shimmer in their treble details especially around the upper-mids/highs region, these don't come across as sounding harsh/sibilant to me which is truly a nice surprise. (although my first 15-minutes impressions when I first opened up my set did sounded slightly harsh or fatiguing, but currently the treble has tamed down alot and smoothed-out after approximately 80-hours of burn-in now)

Although there is a perceived tinge of brightness somewhere in the upper-mids/highs around the 6kHz - 9kHz region to my ears, these phones do not have the over-exaggerated amount of warmth/richness energy or coldish/dry edginess throughout their bottom-end/midrange frequencies as these sounds pretty balanced to me although I can certainly see some people referring them as being treble-heavy.

The CK100PRO does have better texture/articulation in the notes than the CK100 with a slight bit of grain perceived even in well-mastered recordings (take note I have only used MP3s or ATRAC3plus, so relying on FLAC or ALAC may slightly improve matters here). While the midrange still sounds quite smooth/airy to my ears similarly as the CK100, these phones unfortunately has lost the kind of "creamy and liquid" pleasing mid-tones coloration that used to exist in the CK100 model. I suppose perhaps this may be due to the fact that the CK100PRO has being tuned towards a more neutral or balanced presentation (at least according to their product description on their official japanese site by AT), aimed towards achieving a more accurate tonal reproduction which of course isn't necessarily a bad thing here for most audiophiles out there.

In terms of bass response, this was another huge surprise that I wasn't really expecting. Although I have also heard the CK70PRO/CK90PRO before in the past and thought they do very well in terms of bass response due to AT's "Acoustic Horn" patented technology or improved tuning, I think honestly the PRaT factor and bass body/texture details in these are a few notches above all the previous AT IEMs I have heard so far.

These phones actually have a much better pitch definition, body/texture presence and extension quality in terms of the lower-end frequencies compared to the CK100 or even CK70PRO/CK90PRO, but I don't think it can be compared to most of the recent dynamics I have heard which includes the MDR-EX1000/EX800ST possessing those kind of visceral bass qualities that can only be found in most top tier dynamic IEMs usually.

But despite all that being said, there's no doubt to my ears they are considered to be way ahead of the CK100 whether it comes down to bass quality or quantity factor. I seemed to find myself grooving more to the beats of those bassy electronica/trance tracks much more on the CK100PRO, compared to CK100. While I do not think that these phones will satisfy any basshead lovers out there, I do believe that the CK100PRO has enough punch, impact and body presence to rival some of the top-tier universal BAs out there.

Dynamics/Transient Response:

Similarly like the CK100, these phones also have very excellent dynamic range, attack and decay properties. The attack on each notes are crisp-sounding, well-articulated and precise. Nothing much to complain about here, these are probably on the same level as the CK100 in terms of dynamic range/transient response as I can't really make out which one sounds better in this department.
Percussion instruments such as hi-hats and ride cymbals sound off with a good amount of sparkle and shimmer in them with the right amount of ringing/decay timing to them, while snare and bass drums has great sizzle and impact presence to satisfy any rock fans.

Listening to my fav songs performed by rock bands such as L'arc~en~ciel, Asian Kung-Fu Generation and Red Hot Chili Peppers was a very satisfying experience just like my CK100.


The soundstage presentation of the CK100PRO is considered to be slightly changed here compared to the CK100. IMO while this was not very noticeable in alot of "modern mainstream" music found these days, I used quite abit of my own high quality classical/movie/video-game soundtracks to confirm my doubts when I first suspected this and seemed to be able to get some positive results with my findings.

Firstly, the CK100PRO's soundstage does not seemed to have that 3D-like spherical presentation found in the CK100 anymore. From my hearing it does not sound that narrow, in-your-head anymore but renders it better with considerably greater width/depth with a feeling of spaciousness compared to the former. Sometimes when listening to my fav movie soundtracks, I can actually feel that the depth/layering of backing instruments extends up really high or far. (though in terms of width/spaciousness I don't think it is actually ahead of my MDR-EX800ST or even the EX1000s to my ears)

Vocals/Instruments can still be clearly defined, and easy to distinguish apart similarly just like the CK100. But strictly speaking I do think in terms of instrumental separation to my ears the CK100PRO may be a few degrees weaker compared to my EX800ST or Westone's UM3x, as IMO these phones have some of the best instrumental separation I have ever heard in terms of universal IEMs.

It still gives a good sense of air and aliveness in terms of acoustical space/ambience between the vocalists/backing instruments going on in the background, but I think it has certainly lost that 3D-like ambient realism that comes with the CK100 as the resonance/narrow effect was also cut down to a minimum degree such that the spatial imaging is presented quite differently now. Personally I don't think this is necessarily a bad thing for CK100PRO's scenario, this may prove to be more appealing to some people as everyone has different tastes/flavour for this sort of thing especially if they have heard the CK100 before and don't quite like its imaging/soundstage presentation.


These may have a slightly trickier fit due to the design for its detachable cables. For more reference kindly refer to the picture provided by AV Watch Impress for their recommended suggestions on how to wear these for a better seal/fit, but personally for my own case I still wear it according to AT's recommended method as described in their original manual as it works better for my own ears. (the one pictured on the left is AT's suggested wearing method, while the AV Watch editor's improvised method is shown on the right)

Similarly like the CK100, users can use Monster/Shure's tri-flange tip to achieve a better seal/isolation factor for these if they are having trouble with the default silicone tips provided by AT. While Sony Hybrids works very well too, for increased isolation I will always rely on my trusty Monster tri-flanges and since I do not listen to my IEMs outside for long periods, comfort issue is usually not a problem for me here.

Also compared to the past CK9/CK10/CK100 models, this time Audio-technica has also included a pair of M-size original Comply™ foam tips this time to help enhance the comfort/isolation factor for the listener, so if the original silicone eartips (model ER-CKM55) doesn't work well for your case, you can simply rely on that as I don't think in terms of comfort/fit, anyone can complain about Comply™ as their patented foam tips material are certainly one of the most comfortable ear tips ever that one can buy for his/her portable IEM.

According to my own measurement, the size and bore of the included foam tips is actually the same as my pack of Comply™ TX-200s (with earwax guard) as I have been using them for awhile now with my CK100, so I believe the ones that was bundled with the CK100PRO is the T-200 model.

Higher accuracy in tonal reproduction with better bass response, texture body and presence.
A more accurate presentation in terms of imaging/soundstage for some people, as the CK100 makes you feel like you are sitting in black sphere like the GANTZ ball, with a HTRF 3D equalizer messing with your head.
Also much easier to drive despite having a higher impedance rating compared to CK100, volume sensitivity somehow seems much better than the latter as I was able to get similar listening volumes like the CK100 on my Sony Walkman with just 1/4 volume, while CK100 usually requires half of Walkman's volume output to achieve a similar listening level. The detachable cables come with good stress relief on the housings/mini-plug design.

May have listening fatigue for some people, as the brightness level is a few notches higher than CK100/SE535 normal editions and probably on par with the brightness level of MDR-EX1000 perhaps. (to state upfront, I don't have a sibilance/brightness problem on either the MDR-EX1000, EX800ST or the CK100PRO myself as they are all within my tolerance limit)

Not very forgiving to low-quality music sources due to its ultra-high resolution/revealing nature, CK100 seems to be slightly more tolerant with lower-quality 192kHz bitrate MP3s compared to the CK100PRO so IMO using FLAC/ALAC formats will probably be more helpful here. Housing weight also feels noticeably heavier when wearing on the ears straight down, compared to wearing the CK100's straight down. When worn over-the-ears, this feeling is minimised.

P.S : I have used the following Stereophile's Audio Glossary descriptions in my above-mentioned review, in order to help you guys to understand alittle better the meaning of the technical terms used in my review write-up.
Edited by Haonan - 12/12/11 at 5:12am
post #3 of 355
Thread Starter 
Epilogue and Summary:

The CK100PRO definitely possess a higher level of technical prowess/proficiency above the CK100. I think AT has managed to address and fix some of the technical deficiencies/flaws found in the previous CK100 model, one thing I remembered that has been brought up several times on Head-fi as well as in many chinese BBS forums from what I understand, it is reported and shared by many online users that they felt that the CK100 lacked the kind of bass quality/quantity that people can usually find from top tier Shure/Westone BA IEMs.

CK100PRO managed to rectify upon this problem, and while it may never satisfy true bassheads out there, I do think people really need to hear these for themselves and be enlightened that Audio-technica can indeed make a good quality, balanced IEM also suitable for R&B/hip hop/electronica genre, and not just for vocals alone. (of course the CKS aka Solid Bass series excels in those genres, but it's not a really balanced sounding IEM in my honest opinion)

Although it does not have the kind of adeyaka coloration (艶やか is the japanese kanji for this which stands for glossy or can also mean as captivating/enchanting in a same meaning, mainly used for describing CK100's midrange) qualities that was found in the former CK100 model, I think I can confidently say with assurance that the CK100PRO will be a much better all-rounder IEM for all kinds of genres for many people, as compared to the former which seemed to have garnered quite abit of love it or hate it reputation from what I understand.

Some people may ask me, so was it worth the cost of additional 400 dollars over my previous CK100? Well to a certain extent it's a positive yes, I think for now those faster-paced/tempo music with a heavier bass presence or even for classical/orchestral genres, I seemed to derive a much greater enjoyment from listening with the CK100PRO compared to the CK100 due to its more 'balanced presentation'. Was the CK100PRO a few notches above the CK100 in terms of pure vocal performance? I'm afraid I can't answer that question as it's simply a matter of preference in taste/flavour here in my opinion. Despite that the CK100PRO has managed to take a few technical aspects of sound a few notches up compared to the CK100, it's not hard for me to say I won't be selling my CK100 anytime soon though.

So who is this for? In my most honest opinion:
  • You don't mind a tricky fit/wearing method compared to CK10/CK100 (YMMV as usual)
  • You don't like the heavily coloured mids found in CK100 but have always loved the CK9/CK10 signature
  • You prefer to have forward-sounding presentation ala Grados style. (AT's indeed do have recessed mids in some of their headphones/IEMs, but this one's definitely not one of them
  • You prefer to have some sparkle/shimmer in your treble details, or excellent PRaT aka pace rhythm and timing in the lower-ends (note: -bassheads need not apply-)
  • You prefer a more balanced presentation like the MDR-EX1000s, compared to warm/dark phones like the IE8 or coldish phones like the ER4
  • You want a robust build quality/design in terms of cabling material for a universal IEM, with detachable cable options/possibility of using 3rd-party cables in near future to enhance SQ

More comparisons with CK100 to come later. smily_headphones1.gif
post #4 of 355

Great job. Thanks. Those Pros sound like winners.

post #5 of 355
Thread Starter 
Thank you goodvibes for your kind comments. I guess the CK100PRO together along with the recent Sony's XBA-3/XBA-4 would probably garner quite abit of attention around here from now on, since these are considered relatively new IEM releases that are freshly baked from Japan. biggrin.gif
post #6 of 355

They cost like Phonak 232s. You know it wont be long before we get a compare.bigsmile_face.gif I suspect the Sony's will be cheaper, looking for more distribution while making their own drivers for easy assembly. Along with the Finals, W4, 535se and the MA's, there looks to be a new wave of contenders.

post #7 of 355

Haonan, impressive review. Extremely detailed, didn't you said this was your first review? Looks like you've put a lot of time to it :)



Anyhow, hate to disappoint you, but I jumped on Pfe 232 instead of XBA-4 redface.gif. My CK100PRO will be here in 2-3 weeks. Maybe I could do 232 vs 100PRO devil_face.gif


Edited by Bokyung - 12/12/11 at 11:24am
post #8 of 355

Thanks so much for the review, very indepth and detailed. Btw I also love BoA :P

post #9 of 355

thank you so much for the very detailed and excellent review.


post #10 of 355
Thread Starter 
@Bokyung: Hey thanks for the kind words mate. And about your CK100PRO vs XBA-4 comparison, aw that's unfortunate as I was looking forward to that. But never mind I suppose once the Sony XBA series are out in my country either in Jan or Feb next yr, I should be able to audition easily locally here in my country, so no worries about that. smily_headphones1.gif

Will be looking forward to yr CK100PRO vs Phonaks 232 comparison impressions in the future. ^ ^

@tranhieu and pinoyman: Hey thank you so much for the kind compliments, very very appreciated. Yeah it's my only way of giving back something back to the community after joining here for so long, since this is sort of like my first review write-up ever written for Head-fi. Glad that you guys enjoyed reading it. redface.gif
post #11 of 355

I would like to commend you on a great review.  I am both a fan of the ATH-CM7 and the ATH-CK100. 


On suggestion though: I think it might be worth getting some impressions of the ATH-CK100Pro using some high quality lossless sources (FLAC/Apple Lossless).  I know for a fact that the CK100 do scale very well with high quality sources.  Even if it is easy to drive, when combined with a portable amp, the CK100 really sing.  With the CK100, I can actually tell the difference between a 320kbps encoded MP3 file and an Apple Lossless file.  Based on your review, I believe the there maybe a very large difference in the quality of the file, when using the CK100Pro.


Again, I look forward to hearing your impressions. 

post #12 of 355
Originally Posted by Haonan View Post

Before I start off, please kindly take note as I'm not a professional reviewer nor do I have a good flair for writing these sort of technical IEM reviews like how |Joker| or james444 usually does around here, they may not be as descriptive as you may like or expect.


Haha, what an understatement, this is probably more detailed and exhaustive than anything I've ever written. Great job, Haonan, very much appreciated! smile_phones.gif

post #13 of 355

I also just want to thank you for such a great review! 

post #14 of 355

Very well written review Haonan. Do you prefer your CK100 over your CK100PRO for female vocals?

Looking forward to more impressions from you popcorn.gif

post #15 of 355




You don't like the heavily coloured mids found in CK100 but have always loved the CK9/CK10 signature



so, where do i get a loaner pair?

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