Just got my CKX9iS today. I'm so pleased with it and yet at the same time kinda flummoxed by it, that I just have to come on here and discuss my emotional rollercoaster ride in public discourse. Yes, I'm that kinda person, you've been warned.
Disclaimer
My ears may not be as hi-fi as yours; all views are relative and subject to sudden tectonic shifts; our music collections and listening habits may be very different, etc etc et al, are just roundabout ways of saying: your freaking mileage may vary, and don't sue me, don't curse me...
The Seduction
I had the opportunity to sample the CKX9 (demo unit is non-iS, without the remote button and analog volume dial) in a quiet showroom with portable sources: today the fleet consists of two iPod shuffles, a Samsung U5, and two smartphones. It's not often that I take a liking to Audio-Technica's sound; in spite of serving up the trebly highs I so enjoy, they often sound too dry or too flat to my ears, and I often opt instead for an IEM with inherently less treble, then apply a treble-boosting EQ..
But the CKX9 sounds very good to me. I own a few $100 IEMs - the JVC FXT90, UE700r, Sony EX510 - actually they all cost me a little more than $100, but I get the feeling that CKX9 is higher-fi than all of them. In terms of details and layers revealed, the precise spatial placement of sound elements, and maybe a little more energy/fun than even the FXT90. Most of my music - even 70s oldies in a very low bitrate - sound renewed and modern, but at the same time the CKX9 doesn't go overboard on higher-energy stuff like EDM or smooth jazz (yep, laugh away...). This is the quality that sold me.
The CKX9 is not a bass monster, there's just no way when there's a true fart cannon that we call the Sony XB90EX. If you like bass, there's plenty of rumble and fire to keep things enjoyable, but the CKX9 is simply not as dark as the XB90EX, the overall balance bears more resemblance to Sony's non-XB offering in this price range, the EX510.
But Do I Pull the Trigger?
The showroom had other products. The CKM77 and CKM99 with their metal housings are more precise, corresponding to the sensory pleasure derived from sharpness in a well-focused picture. The "solid bass" CKS99 seems more bassy, at the expense of some separation and clarity. It might be that the CKX9 demo unit isn't burned-in adequately, but it trades these other IEMs' refinement & control for a little straight-forward fun - the trade-off is very subtle and you can absolutely have fun with any of them, but since my obsession was with the CKX9 first, I picked up a black pair, in the iS version for its analog volume thingy. At $90, less than half of the CKM99's price, it punches above its weight and is a great, great deal.
The Fall
My previous ATH purchases have always sounded very dark out of the box, and take a few hours to a day to open up; not this pair, it sounds impressive even as is, so that's not the source of my pain. Call me silly, but it just hadn't dawned on me until I left the showroom that the CKX9 doesn't offer much isolation. This is not a fit issue; there's a tiny vent facing the inside of your ear canal that lets sound in, and no silicon tip (or the bundled Comply Action foam tips) can defeat that tiny vent. You could tape up the vent like I tried to, but that changes the sound beyond recognition.
Some of my favorite IEMs have always been only semi-closed: The Sony EX90 that head-fiers don't really care about, and the Philips SHE9500, and my Sony EX510, are all like this. I cannot resist the bouncy airiness in their timbre. But I often crave so much peace and quiet while I'm out and about, that I don't know if I'd made the right call. In silence the CKX9 is still super-persuasive, in the same way love songs bitch about "how can something feel so right & turn out so wrong?", so I'm going to do the obligatory? 200 hours burn-in and see what happens.
Addendum
I did not try the CKX5, but I tried the CKX7. It sounded smaller, darker, more vocal-centric, and was easier to wear. It sounds more like my existing IEMs. With only $20 difference between them, and a desire for something new, plus a superstition that I should avoid the numbers 5 and 7, I insisted on the CKX9.
