I just received a KBEAR KB04 review unit from KBEAR.
This is just a OOTB first impression with minimal burn in (using stock tips/cables), but it is quite a good budget set. It is a 1DD + 1BA set, and at the $30 price, it seems better tuned than some similarly priced 1DD + 1BA sets eg the Jade Audio EA3.
Build: Well built, metal chrome shells. On the slightly heavier side of things. May be a fingerprint magnet for the OCD among us, but it is comfortable and well fitting, no weird poky edges. No driver flex.
Accessories: Comes with SPC cable, a bit thin, but flexible and should be usable OOTB. Most audiophiles will probably upgrade the cable, but considering the cheap price, I think KBEAR had to save some money at the cable area. 2 different sets of silicone eartips are provided (one with narrower bore, one with wider bore), will try them out and A/B more. But the tips are good fitting, no need to mess around with aftermarket stuff like the BLON BL-03.
Isolation: Very good, considering it is vented.
Sound: Harmanish tuning, subbass extension/decay/quantity is a bit on the thin side considering it is a DD bass (sorry I'm a basshead). Mid bass is definitely lesser than some sets like the BLON BL-03/KBEAR Diamond, so those that want something approaching a bass just slightly north of neutral might appreciate this set. Slight midbass bleed. Bass seems quite fast for a DD set, quite accurate note placement. In fact if the KBEAR specs didn't specify a 1DD + 1BA config, I would have thought the bass was a BA bass.
Mids slightly recessed in the lower mids. Upper mids are boosted and occasionally can get shouty with certain tracks. Lower treble is boosted with higher treble roll off. Minimal sibilance.
Soundstage: Above average in width.
Technicalities: Above average clarity/details. Good imaging/instrument separation.
Timbre/note weight: Note weight on the thinner side. Slightly artificial timbre for the treble frequencies for acoustic instruments. Timbre slightly dry for vocals. The timbre in the bass frequencies (covered by the DD) is quite good and natural.
Drivability: Does well from low powered sources like smart phones and will make a good on the go IEM. Scales better with amping in the areas of soundstage and details.
Will drop a more detailed review after spending more time with the KB04, but for the price of $30, I think it will be a good set for those new to the hobby and those wanting a good daily beater budget set. Experienced audiophiles will probably own something better (though more expensive). But the KB04 definitely boasts good price to perfomance ratio. I remember paying more than 10 times some years back for my Westone 3 (3 BA driver) to have something very similar in technicalities as the KB04 (though Westone 3 was more V shaped in tuning). I suspect the upper mids harshness can be tamed somewhat with different eartips, will explore more and report back.
EDIT: I am pleased to report that with different eartips (eg wider bore ear tips like tenmark whirlwinds), the upper mids can be tamed. But of course we all have different hearing health, different ear anatomies and different treble sensitivities. But I would strongly advise to try the KB04 with different tips other than just the stock ones, you might just hit on a certain configuration that gives you the Eureka sound!