It has been a long time since i have used the ck10 so i would be purely speculating. However the c3 is not a bright player nor dark like sony or 601 it sits in the middle for me which is the sweet spot and has a lot to do with why i like it, as i previously mentioned it has a slightly mid presentation and I have had no problems at all with sibilance or fatigue from highs.
Bass performance is good with sufficient quantity and great quality but shigzeo did point out it rolled of a touch but no more than any other player. Used with my more bass heavy eph-100 its a dream.
With low Ω earphones. I took the measurements myself and it is typical, at least it doesn't get waffled, but simply and gently falls off after 100Hz.
EDIT: sound of C3 is pleasing, for sure, and size is perfect (a bit bigger than the 3rd gen iPod nano 'sumo') and well put together. UI seems okay. If you are used to Cowon players, you know what to expect in terms of bass roll off (minimal, but can be heard in some cases). Low noise floor. Luxury feel. I think it doesn't come with earphones, but here at headfi, that isn't a big deal at all, is it?
There is very little hiss and the signal is strong well till near 90% or so for powering external amps.
*It is of my opinion that shigzeo experienced the player on old firmware before the release came with the button fix, works well now as demonstrated in the video.
another user Nikosirus commented:
Got hold of a C3 today. Sounds great. I have had a ridiculous number of music players over the years and I think I'm going to prefer it to anything I've heard except for the HifiMan players and the M6SL. So that's better than anything that I've heard by Cowon, HiSoundAudio, Teclast or iRiver. Just my opinion of course, but what else can I say?
If I can level any criticism at it I would say that it's not exactly overly bassy, but I can live with that - particularly if I listen to it with the decidedly bass-heavy Radius DDM. Also It has failed to play a couple of songs, throwing up a 'file error' message. Only a couple mind, and I may yet discover why - you know how some players are ultra-fussy about tagging.
Build quality is top drawer and whilst the interface is not the most intuitive you get used to it pretty quickly. Got it super-cheap on eBay from Hong Kong too, and got the fancy Colorfly box, mains charger and PAA-1 earbuds in the package. If nothing else I'd call it a bargain.
*he later discovered the file error was due to a badly formatted microsd and admits it was no fault of the player
Edited by stozzer123 - 9/5/12 at 3:29pm