I'll admit it, I had low expectations for this set. Not necessarily because of the price, but the concept of combining bone conduction with a dynamic driver just seemed to me to be a potential train wreck. I'm happy to say I was definitely wrong on that score.
I'll add a disclaimer here that KBEAR contacted me out of the blue to ask if I'd be interested in reviewing the KB02. I've been contacted before by companies, and I usually politely decline, but I was curious how this combination would sound. I fully expected to give a negative review, but that won't be the case here. Don't get me wrong, these are no giant killers IMO, but the tuning is much more coherent that I thought.
I'm not one to go into unboxing, and I don't think there is much to go over in this case anyway. Generic box, IEM, 3 sets of eartips with 3 sizes in each set. Wholly adequate given the price tag (currently $39.99 USD) and well presented but nothing worthy of note.
Build quality is a bit better than I might have expected. They're very light, which might feel cheap but there are no seams I could find that might come apart, and the color scheme is attractive for my tastes. The logo I could do without, but it isn't too bothersome. They're calling the material a "delicate resin" which might contribute to the lightness.
There is the interesting vibration you can feel when you knock the shells which is obviously a result of the bone conduction technology these are constructed with.
Fit was decent for me, though this is going to be different for everyone. The KB02 has a rather large and short nozzle, which seems to fit my ears best. The included tips are fine, but tip rolling changed the fit and sound, and would be worth experimenting with. I had the best results from some conical shaped tips I have from Hidizs, but had no problem with the smallest sized Sony tips I had on hand as well. I settled on some very wide bore double flange short tips from Cardas for the majority of my listening.
Another contributing factor for my unfounded fear of the tuning is KBEAR's own marketing, which self proclaims "Ultra Strong Bass". Combined with the beryllium coated driver, which I usually associate with a steely piercing treble, I was a bit reluctant to try these.
As previously stated I instead found these to be coherently tuned and more even overall than I expected. At the risk of touching the live wire of an ongoing argument, I'll note that I found that these did need more burn in time than I'm used to (about 70 hours) especially for IEMs which I rarely find burn in to be useful for. Whether or not you believe in burn in or not, this was my experience,YMMV.
Once they did have that much time burning in, the treble smoothed out considerable, as I found it particularly harsh, unnatural and fatiguing straight out of the box. I don't think the KB02 is particularly well extended in the treble, but I didn't find myself wanting.
The upper mids can be a bit too forward on some tracks, but I found this to be mostly track dependent and had little problem for the majority of my listening. Those who are particularly sensitive in this area might want to look elsewhere. Otherwise the mids were pleasing and satisfying overall.
The bass was definitely better behaved than I thought it would be. I'll agree that the KB02 has "ultra strong bass" when called for, but on most recordings it is well behaved and unobtrusive. When called for there is a definite uptick in the sub bass and while it's not skull rattling, it is powerful and noticeable. I honestly wasn't sure how it would integrate with the rest of the sound, but I found it to be seamless and not distracting. There's a bit of a lift in the mid bass but it never smears into the mids, the emphasis is more centered on the sub bass. I think the highest praise I can give is that the bone conduction doesn't call undue attention to itself, but definitely adds some fun with bass heavy music.
Overall detail is very good but not earth shattering, which is forgivable at this price IMO. Again I don't find KBEAR to have dropped the ball, but I wouldn't confuse these with higher end earphones. The bass isn't over flabby, but not super tight either. There's a decent headstage but it's not enveloping; fairly wide but not too deep. There's actually plenty to like here, and I think it only falls short comparing to higher priced offerings.
In the end I find the KBEAR KB02 to be a compelling buy at around $40. I'll say it again, the tuning is much more mature than you might expect. While not a "reference tuning" by any stretch of the imagination, I found the bass boost to be even handed and fun to listen to, and the rest of the frequency response was solid to boot. The KB02 is well worth checking out.
