The way Audio Technica labels their products, we would think the CKM is like the CK in some way, but it's really not at all. The CKM products is much cheaper and often less liked.
DBA-02 and CK10 are not very alike at all. I don't know why people keep saying that. They really are very different sounding earphones.
The DBA-02 did not impress me much. It seems geared for a particular task, but as a general music listening device, it isn't great. Dynamic range is compressed a bit. There is lack of texture/articulation, and the bass driver is very, very lean and can not match the presence of the high frequency driver. Even when EQing was applied, it didn't balance out well. The DBA-02 seems to be engineered to do recording work, as in make you hear all the sounds, but it ends up not being the most musical device. For reference to another budget minded set, I would pick the RE-ZERO over it every day of the week over the DBA-02 as it shows better balance, better realism, better texture, and even more bass and the RE-ZERO is a bass lean earphone itself.
The CK10 is vastly superior to the DBA-02. The speed, texture, and level of detail of higher frequencies is unmatched by anything the market. It's well balanced short a moderate peak at 10kHz. I have a slight personal preference towards the CK100 myself, but it is sort of an apples and oranges kind of comparison. There are simply geared quite different. The CK100 doesn't carry the level of texture and micro detail the CK10 has, but the CK100 has a better balanced presence and more refined up top and more presence and hit down low. In some ways I could call the CK10 better like with the texturing and micro detail. In some ways I could call the CK100 better like a more even presence across the spectrum and better sound stage separation and placement. At the time I had a pair of CK10s, I would slightly prefer my RE252 over it, although I saw the CK10 as technically more correct earphone. Right now I own the CK100 and also have a RE252 again. I slightly prefer the CK100 over the RE252. I can't say that I would pick the CK10 or the CK100 if I owned both and compared. They do different things, but I do suspect I'd lean slightly towards the CK100 if I had to stick with just one. I do feel the CK10 does need EQing too. The treble peak is a moderate issue with that earphone. Comply foam tips can help and make it acceptable without EQing, but really EQing makes it significantly more balanced. The CK100 doesn't have such a need. There aren't that many earphones that offer a really outstandingly flat frequency response. The CK100 is one of the few which also means it will sound well with a wide variety of music.
As for a budget level product, say $150 or less, I will point you to the RE252 all day long, a used pair. It is the most balanced, reference level IEM on the market. It does have a few specific faults, mainly a constrained dynamic range that tends to suck some of the "pow" and effortlessness out of the sound and the bass is there but lacks the shear presence to be full (although it's got good impact). It's sort of what you get when you put a speaker in a really tiny enclosure. It sort of gets constrained, and that's kind of how it sounds. It's just a really, really good driver that's very well balanced in that compromised setup. The RE262 is a better choice for a non-constrained sound,and uses basically the best dynamic driver in existence (it's ridiculously good) but the RE252 is more balanced and 90% as good as the RE262 in sound. The RE252-RE262 toss up is an incredibly hard one, but the RE252 can be had cheaper and the better balance makes it work better over a wider range of music.
