Kinboofi MK4 Review – Famous Soon?
by Jürgen Kraus
Pros — Audiophile tuning; good tonal accuracy; very easy to drive at 22 Ω ; hand-crafted shells; high-quality MMCX connectors; great cable.
Cons — Large earpieces; meager accessories.
You find a series of detailed photos showing the anatomy of the Kinboofi MK4 on our blog HERE.
EXECUTIVE SUMMARY
A well-resolving, mostly neutral (but never sterile) sounding earphone with a tepid low end.
INTRODUCTION
Kinboofi is a Chinese junior company with an unusual sounding name so cryptic that even Kinboofi could not tell me much about themselves in their humbleness. I contacted them via their amazon store to get some basic information, but all they had to say was that they didn’t have a “famous history” and that they wanted to be as well known as Knowledge Zenith. Quite frankly, Knowledge Zenith likely do presently not offer a model that can sonically compete with the MK4.
SPECIFICATIONS
Product Name: Kinboofi MK4 4BA In-ear Earphone
Type: In-ear
Drive Unit: 4BA Balanced Armature drive unit each side
Impedance: 22 Ω
Headphone Sensitivity: 116 db
Frequency Range: 20-20 kHz
Interface: 3.5mm
Cable Length: 1.2 m ± 5 cm
Color: blue
Cable: Silver-Plated, no mic
Earphone Interface Type: MMCX connector
Price: $259 (at the time of this review)
Product Link: Wooeasy Earphones Store
IN THE BOX…
…are two identical (but differently coloured) sets of eartips (S, M, L), cable, earpieces, and a small case.
PHYSICAL APPEARANCE, HAPTIC, AND BUILD QUALITY
The beautifully and sturdily built resin earpieces are rather large but fortunately also quite light. The included pearly white six-core silver-plated copper cable is extremely soft and flexible and has zero microphonics (but also no chin slider). It feels silky smooth between the fingers. I usually don’t care much about cables but this one is great. The MMCX connectors are robust and of a higher grade than the ones I had experienced previously. They were tight to begin with so that I had problems getting the cable connected for the first time. And after numerous forced dis-/re-connections, the connectors remained tight and precise.
ERGONOMICS, COMFORT, ISOLATION, AND FIT
Despite their large size, the earpieces are comfortable and, depending on insertion depth, isolate well.
SOURCE AND EARTIPS
The Kinboofi MK4 were very easily driven by my iPhone SE at their 22 Ω impedance. In fact, adding the Audioquest Dragonfly dac/amp created amplification overkill. The largest relatively long and slim included green-and-grey eartips worked well for me.
TONALITY
JK’s tonal preference and testing practice
The low end has a flavour somewhat between a BA and DD in terms of composition and speed. It is not particularly textured but rather linear and adds a bit of warmth to the otherwise more neutral overall image. Call it tepid. The low-end is definitely above neutral, though not by much. It is well extended and stays reasonably well composed all the way down. Luckily, the mid-bass hump of so many dynamic drivers is missing and the slam of a more or less realistic magnitude comes from the lower-bass/sub-bass transition. The low-end is quite pleasant to my ears and develops sufficient impact to please — without being “too much”. Nevertheless, changing tips can generate a different bass perception. For example, the largest tips included with the Moondrop Kanas Pro [review] created an almost boomy bass. Results may vary from ear to ear.
The lower midrange is slightly recessed, close to neutral, and therefore not at the upper end of the “richness” spectrum. Male voices are rendered realistically but are not particularly warm. Female voices are well sculptured and with good air, and they can be still slightly back to reasonably intimate. The upper midrange is relatively smooth and does not develop a general harshness but it can be a bit overwhelming at times. The whole midrange is characterized as close-to-neutral with great speech intelligibility and resolution. I find the transition from the low-end (from warm to neutral) could be a bit smoother.
Treble can be somewhat inconspicuous. Cymbals and snares can sound realistic in some pieces and plasticky and grainy in others. The Kinboofi is certainly not a treble-forward earphone but also none with unpleasant peaks. Nevertheless do the upper treble peaks create some air and possibly some fake resolution.
Soundstage has a good width with some depth and it is rather high. As a difference to cheaper earphones I have tested, the stage is simply bigger with better spatial cues. Resolution is excellent and better than in any of my $100-150 earphones tested: high and low notes are separated well (e.g. Rammstein’s rhythm guitar on the low end and keyboard at the high end). Micro-resolution in the treble may be lacking a bit. Violins develop great micro detail I can’t hear in cheaper models.
Timbre is good albeit not quite as organic as it could be. The Kinboofi MK4 does sound like a BA earphone, which is less organic than, for example, the new Sennheiser IE 500 Pro single DD. In comparison to $100 earphones, the Kinboofi have a more substantial image and more of a concert hall feeling to them. I also find that the MK4 as well as my Ultimate Ears 900s start distorting at relatively low volumes, whereas I can turn up the single DD Sennheiser IE 40 PRO ad infinite, but this is a general BA issue.
CAN THE KINBOOFI MK4 BEAT MY ULITMATE EARS 900s?
I don’t have many earphones in the Kinboofi MK4’s price range to compare them to, but coincidently the $399 Ultimate 900s [occasionally $179 at Massdrop] are one of my go-tos. The UE900s also sport 4 BA drivers (all by Knowles] stuffed into much smaller earpieces than the Kinboofi MK4’s, which are connected by a selection of two terrible-quality cables. The more neutral MK4 present a more natural midrange against the smoother, more coherent but also more coloured UE900s. The MK4 also have a better build, a higher soundstage, whereas the UE900s have superior imaging, separation, and resolution. Bass is of a more BA-type for the UE900s, but very well executed…very dry…and more textured than the Kinboofi MK4’s, but also more boosted. Both earphones don’t have any part of their frequncecy spectrum overly exaggerated, which makes each of them good a non-fatiguing listen that should appeal to both the fun crowd and the analytical crowd alike. The MK4 work for me for many genres from classical, jazz, through rock and pop.
But to answer the question: there is no clear winner, both earphones, the UE900s and Kinboofi MK4 are certainly in a similar sonic league imo.
CONCLUDING REMARKS
The Kinboofi MK4 have passed my test. Who may think the name Kinboofi rhymes on goofy will stop laughing soon when the company will be a household name. Kinboofi may not be as big as Knowledge Zenith but they certainly have a product in the MK4 that is arguably superior. In today’s world, where a $200 earphone has become as disposable as a bottle of wine, the beautifully handmade Kinboofi MK4 could be a good candidate for a go-to earphone with a long shelf life.
KINBOOFI MK4 QUICK SECOND THOUGHTS
by Biodegraded
Pros: Build, cable, even tonality, easy to drive
Cons: Bulk, incoherent timbre, sensitivity to amplifier impedance
The tonal balance of these is good, without the overemphasized bass or elevated treble of many Chinese earphones. The treble though can tend to hissiness and sibilance on revealing recordings. The quick-decaying BA timbre is very noticeable, particularly in the highs, and it seems that the multiple drivers don’t play together very well, giving a sense of incoherence. I couldn’t decide if it was that or if it was true distortion that gave rise to a fuzz that I know isn’t there in certain mid-centric guitar riffs, but the effect was disconcerting.
Also disconcerting was the impedance profile. With impedance varying >5x from a low of 5 ohms around 10 kHz to a high of 56 ohms in the midrange, these will react strongly to the output impedance of the amplifier they’re driven with. In the plot below, compared to an assumed zero impedance reference in red, the frequency responses with amps of >3 ohms (blue; ‘iEMatch’ output of ifi Nano BL), 5 ohms (purple; older iPhones), 10 ohms (teal; some Topping amps) and 23.5 ohms (tan; SE output of Loxjie P20) show increasingly darker tilts: bass and lower mids up, treble down. I spent most time listening to these with the Audioquest DragonFly Black (< 0.5 ohms) and my phone (1.2 ohms).
Despite their bulk, I found these comfortable to wear for extended periods and with the stock tips I found they isolated well. Like a lot of recent ‘budget’ and ‘mid-range’ Chinese-made IEMs, the supplied cable is excellent and together with the solid construction gives the impression that these are serious iems.
In conclusion: I liked the tonal balance, but not the BA treble timbre and the multi-driver lack of coherence, and whatever was causing the midrange guitar fuzz. I worry too that people with different amps (or phones) will hear these differently; on the other hand, if you have amps with rather different impedances, you might enjoy the differences in tonality they’ll provide.
DISCLAIMER
The pair of Kinboofi MK4 was supplied by Wooeasy Earphones Store for our independent reviews. Thank you very much.
Our generic standard disclaimer
