Disclaimer: I purchased the Audio Technica CKM55 directly from Ocharaku.
The Audio Technica CKM55 started life as just another IEM in the sea of entry level IEMs. The stock CKM55 has a typical entry level boombox tuning with plenty of bass, recessed midrange and unpleasant highs. Then Ocharaku came and installed their Tornado Equalizers into the CKM55 and changed the life of the CKM55 forever.
Perhaps intended as proof of concept to the benefits of the TE (Tornado Equalizers — you can download the white paper by clicking on this link), the Ocharaku modded CKM55s consists of nothing but the equipping of the Tornado Equalizers. Gone is the boombox tuning of the original CKM55s replaced by a proper tonal balance from top to bottom. The tonality is moderately dark, clean, and clear. The soundstage depth and width are good and spacious, the bass and mids full bodied and smooth. The sound signature is warm and relaxed, something that almost anyone can enjoy.
The mod comes in several variations. There are three different canal lengths to choose from: short, normal, and long. The length of the ear canal is different from person to person and you can audition the different versions and determine which one sounds the most neutral to you. You can also choose a mod with a soft treble than the default tuning, or going the other direction a mod with a more pronounced treble. In all, between the choice of the canal lengths (short/normal/long) and treble tuning (soft/normal/pronounced), there are nine different variations of the Ocharaku CKM55s.
The tuning variations have the same basic signatures though with an altered tonal balance. Testing the blue color coded for short canal lengths gives me a thinner, slightly recessed bass body that just doesn’t feel quite right. The red color for longer canal length pushes out the midrange more than the stock but not in an extremely colored way, while the light green color has an even softer treble than the relatively laid back treble of the default set up and is my personal favorite of the bunch.
Other than the blue color mod which is designed for short canal lengths (primarily women, Mr. Yamagishi said), I felt that the three different tuning of red, dark green, and light green are all very pleasing and natural to listen to. The laid back and relaxed tonality, while not as resolving and as accurate as the Flat-4 models, are much friendlier to the ears and may very well be a strong candidate of being one of the most special dynamic drivers in the market. Obviously they are far below the Flat-4s in terms of technicalities, but I just happen to enjoy how enjoyable a proper warm sounding dynamic driver IEM can sound. For 10,000 yen that it’s being offered for, I think these are one of the best buys out there. The superior dark background and soundstage depth to even the highly regarded VSonic GR07 (I’m using the GR07 bass for this comparison) makes this IEM one of the best mid-level dyanmics in the market. It would be interesting to pitch this against something mid-end like Sennheiser’s IE80, but I happen to not have a demo unit around.