Hi audionewbi, you are welcomed. Glad to know you went with the CK100pro's, you won't be disappointed with its SQ I can assure you, it has a much greater linear response and genre bandwidth compared to the previous predecessor flagship IEM, the CK100 and although the midrange response is not as silky/liquid compared to the former (in my own words CK100 is a mid-centric IEM and has quite abit of coloration), it does bass/treble extension much much better and very apparent when you are using a decent portable source with it. You may have noticed that in my original review, I used the Sony NW-HD5 HDD Walkman which is quite an old Sony player, about 6 yrs+ old. Around February again this year I moved up and upgraded to the NW-Z1070 Sony Walkman Z series, and again perceived an overall improvement to its sound quality. So as long as you have a capable portable source/DAC, you may start to notice gradual and discernable SQ benefits or improvements as long as you use it along with higher quality music files. (ever since I moved up to the Walkman Z, I have only used/relied on MP3 bitrate files rated at 320kbps CBR LAME, and also FLAC Lossless so far, while previously in my NW-HD5 setup it was a mix of 320kbps and ATRAC file rated at lower bitrates)
The hint of sibilance you may have encountered with your pair is perfectly normal if your pair is still relatively new and fresh out of the box without much burning in periods, reason why I say this is because before I wrote and finished up this impressions review for my own CK100PRO's set, before it manage to hit 80 hours there were signs and hints of sibilance issues to me too, mostly with my female pop vocal tracks. I have covered before in one of my posts around here that usually 5 - 8kHz in terms of the FR response chart at this region it adds sparkle and/or treble clarity/energy, so if the music CD tracks that you currenty own/listen have already been overprocessed/equalize by the recording studio by adding gain to it (alot of mainstream pop/vocals CDs out there these days tends to suffers from this syndrome, so don't be caught too surprised by this fact), you will "feel" this sibilance issue as the 5kHz to 8kHz region of the CK100PRO's will indeed be more obvious to the listener, as this is an pretty neutral/analytical IEM with a slight FR tilt towards upper-mids/lower treble. (like you say, it shares certain DNA features/signature with the Etymotic ER4S, and I would agree with that but it's such a cold/lean IEM like the Etymotic, the midrange body is fuller and has more presence and its bass/lower-mids are not that deficient for listening to mainstream pop, unlike the ER4 which can sometimes sound quite lean to me in terms of lower-mids/low-end frequency response when it comes to my japanese pop, my personal experience is with the ER4P version only, not the ER4S as I don't own a portable amp back then when I tried out those Etymotics)
You should experience some better improvements by "not hearing" the sibilance parts after getting yours fully burnt in, I don't experience much issues with regards to the treble now with my Walkman Z, and this was also concured with the post I have posted awhile back, just look at that Mobile01.com discussion post if you don't get what I mean. I do agree with what someone else had mentioned on this thread before though, CK100PRO seems to benefit from added electrical resistance in terms of adding Ohm resistance to the yr player's output, so if you have any 75Ohms resistance adapter lying around (I have the original Etymotics 75Ohm resistor all along so I usually use it with my portable amp before connecting to my NW-Z1070) so you should probably use one if you can find one, it actually benefits the whole FR response in that the bass quality becomes slightly smoother and you may feel that the upper-mids/lower treble response gets smoothed out quite abit more, instead of being "shouty" or hearing too much energetic sparkle/shimmer depending on how you view it. However I wish to emphasize that since each and everyone of us hear things differently via all IEMs/headphones as per usual, some people may prefer this "shouty" or "more energetic upper-mids" syndrome, so it's not necessary to use the resistor adapters as well according to one's preference. For my case when I use it straight from the NW-Z1070 headphone out, I do not use it with any added resistance input to it because it just sounds great out of the Z1070 without giving me any sort of background noise hiss issues. (the TTVJ Slim/Audinst AMP-HP in my current possession is not totally black in terms of noise background, and because the CK100PRO's are pretty sensitive IEMs by themelves thus I try to use it with the 75 Ohms resistor adapter whenever possible to cut out background noise)
As for IEM hardware failures/build quality issues for the CK100PRO, I just wanna share with you as far as concern on this thread and in my local forum's dedicated thread discussion, so far there has never been anyone who had build quality issues with the CK100PRO except for fellow HF member Bokyung. Anything can happen to your IEMs if you are not careful yourself, and judging from QC/build quality on majority of flagship universal IEMs out there, I would say Shures have more problematic cases on many accounts, from the amount of feedbacks online and in my local forum. This dude from my local forum only had the Shure SE535 LTD edition for only a month, and within this period the nozzle on the earphones just broke suddenly without any abuse, he just mentioned that when he was changing eartips the unfortunate incident just happened. I have been changing silicon eartips on my own pair for the last 1 year (I got my pair since late November and finished up my review by early December last yr as I was one of the early first owners for the CK100PRO's since i placed a preorder) and so far I have never encountered any build issues in regards to the nozzle.
Not trying to say Bokyung's incident was a special "isolated" case, but as with all electronic products many things can happen to any other IEMs out there due to user fault/mishandling etc, and it's their own responsibility to get it replaced within the warranty exchange period since all along to my knowledge/experience, Audio-technica has excellent warranty coverage for all their products and has never failed my expectations. Although all my own ATH IEM/headphone products have never failed me in terms of build quality, I did handled some warranty exchanges for my friend's Audio-technica headphones before since I have my own contact in Japan, and Audio-technica san has been very very understanding on all accounts, replacing the damaged/faulty products with brand new sets. (You can go read the ATH-CK10 appreciation discussion thread in this forum, one of the recent owners W1CKED had his CK10 replaced with a brand new pair, despite that I know since March 2012 this year Audio-technica has already discontinued both CK10/CK100 products globally.
Just trying to assure you thats all and sharing my personal experience in terms of build quality, for ATH's IEM products. Enjoy your new IEMs!
Negative/False report. My iPod Touch 4th Gen 32GB (I had it with me since 2010) with 7-8 Ohms output impedance rating doesn't sound quite as musical as my NW-HD5/NW-Z1070 Sony players. TTVJ Slim with only 2 Ohms output impedance sounds fantastic with my pair of CK100PRO's, and also the Audinst AMP-HP as well. Yes it's not a coherant comparison I know, since TTVJ Slim and AMP-HP are not dedicated DAPs but what I'm trying to say is, you cannot judge an IEM's sound qualities/traits by just basing on hear-say/rumors. You need to get down to listen to the CK100PRO's for yourself, in order to understand what you are saying.
I would like to share with you as well, even though you may have gotten a general consensus that majority of Cowon products are well-received in this forum, I'm one of those who do not quite like what I'm hearing from my friend's S9/J3 models he had loaned me, for trying out with my own pair of CK100/CK100PRO IEMs sometime back. Cowon's have noticeable bass roll-off issues to my ears (it's been quite well-discussed in some forums, go search up online sites like iAudiophile.net and Anythingbutipod) and when the CK100PRO's are paired with the S9/J3, it has very strident/clinical sounding dry treble properties, not what something I would refer to as "musically involving". This was without enabling its built-in presets or customising any of those BBE and Mach3bass settings as I was trying to judge the true nature of Cowon DAPs when I was interesting in buying one back in 2011. Unfortunately it failed my evaluation so I continued to stick with my old Sony player, and it was only until this year Feb that I finally jumped on a new DAP, in the form of the Walkman NW-Z1070.
I hope the above clarifies any doubts that you have, regarding the CK100PRO's.
