Introduction

 

Kefine is already well known for the Klanar, the Delci and the Delci AE, and they have just launched a new product: the Klean. In this review, I am going to speak about this new product and compare it with some other products from other brands. Since my first set broke, I borrowed one set from a friend and slightly edited the review accordingly.

Technical Specifications

• Driver Configuration → 1 x 10mm DLC Dynamic Driver
• Impedance → 32 Ω ± 15%
• Spec-sheet Frequency Response → 20Hz-20kHz
• Nozzle Diameter (widest point) → 6mm
• Sensitivity → 107 ± 1 dB
• Cable → 1.25m detachable silver-plated copper cable with 0.78mm 2-PIN connectors
• Plug Type → 3.5mm

Packaging

The packaging of the Kefine Klean is rather sample and contains:

• The Kefine Klean
• The detachable cable
• One set of silicone tips
• One pair of different nozzle filters to tune the sound
• Carry case
• User manual

I would really like companies to include at least two sets of different tips, one set isn’t enough in my opinion.

Design, Build Quality, Comfort and Isolation

The design of the Klean is… “clean”: the metal shells are superbly crafted and are painted in black color. The faceplate only shows the KEFINE brand logo, providing for a minimal design (just like every other KEFINE’s set).

The earpieces are very comfortable, the nozzle is long enough to grant a decent insertion depth and even though the stock tips aren’t enough to do some proper tip rolling, the fit is already pretty good with them. The earpieces are slightly heavier than average but they are built to last.
The isolation from external noises is average.

Cable

There are some other brands who include a slightly better cable in the box, but the Klean come with a stock cable that is perfectly in-line with the price range.

Sound

 

GEAR USED FOR THE TEST

• DAC: Topping E30
• AMP: Topping L30, Fiio A3
• Mobile phones: Samsung Galaxy S7 Edge, Xiaomi Mi A3, Samsung Galaxy S23 Ultra
• Moondrop May’s DSP cable with PEQ=0
• Dongle: Apple Type-C dongle, Fosi DS2, Hidizs XO
• Portable DAPs: Benjie S8/AGPTEK M30B
• Bluetooth Adapters: KBEAR S1, KZ AZ10
• Other sources: Presonus AudioBox iONE, Elgato Wave XLR

Do they need an amplifier?
No, an amplifier is not strictly needed. An amplifier slightly tightens the low-end but it’s not a night and day difference since the driver is already quite efficient.

Sound signature
The Kefine Klean are U-shaped.
The description of the various frequencies will be based on the stock silver nozzles, whereas at the end of this section you’ll also find out what are differences with the black nozzles.

Lows
The sub-bass and bass are forward in the mix, with proper punch, extension and control. The bass is of good quality, and even though not the punchiest out there, it’s still impactful enough to grant a good reproduction of most tracks, even those that focus on the low-end dynamics.
It’s not a basshead set, but those who love some added bass will definitely like the Klean.

Mids
The midrange is slightly recessed, with more focus on female vocals than male ones. Male vocals and acoustic instruments still have proper weight and warmth, which is good news considering that on most U-shaped sets they lack depth and presence.
Female vocals are spot-on, energetic, lively, never shouty, providing for very enjoyable sessions with female singers’ tracks without becoming fatiguing.
It’s not a set for those who like an uncolored and neutral reproduction, but those who like some coloration will certainly love the way the Klean do it.

Highs
The highs are lively, they pack a good amount of detail, and the general tuning of the upper range isn’t neither aggressive nor fatiguing. I think it’s the type of low-end that will fit most listeners provided that you like a very soft touch of added energy and spice. The upper treble has decent extension too, yet without becoming fatiguing or artificial.
There isn’t any kind of sibilance too, which is great news.

The soundstage is well rounded with nice width and average depth and height. The imaging is very good too for the price range and so can be said for the overall layering.

BLACK FILTERS vs SILVER FILTERS
Pretty easy: the black filters increase the upper mids and the treble, improving the overall energy and the detail retrieval, and slightly reduce the low-end presence. I personally find them a bit too aggressive for my taste, the silver filters make them a lot more balanced, natural and pleasant.

Some comparisons:

Kefine Klean vs Kefine Delci
The Klean is basically a cleaner and more balanced Delci: slightly more lively and airy female vocals, a tad less treble “spice” due to less emphasized mid-treble and a softer upper-end roll-off. The result is a more correct reproduction of vocals and more coherent sound along the spectrum.
Technicalities are 90% identical, but the Klean has a touch less soundstage width and slightly more precise imaging.
The build quality is good on both sets, but comfort and isolation are better on the clean, also thanks to the thicker shell that provides for a deeper and more stable insertion in the ear canal. The cable is not that different even though Klean’s cable looks a bit better, and the overall tips’ selection isn’t that different.
I’d say just get the Klean since it’s a more mature and more refined Delci, that’s all. If KEFINE told me that Klean’s driver was the same used on the Delci, I wouldn't even read the specs and I would believe that since the technical prowess is quite similar. If you already have the Delci, instead, I would not buy these: there’s not enough difference in performance to justify the expense for the Klean.

Kefine Klean vs Sivga Que
The Que are slightly less U-shaped than the Klean, with inferior end-to-end extension and more forward mids. The two don’t share much, but we could sum-up the comparison by saying that the Klean sounds overall more engaging and lively with a fuller low-end. They also sound a bit more technical and snappier than the Que. If the Klean will be sold for a lower price, then the Que could experience some hard times.
The imaging is better on the Klean, whereas the soundstage is of similar size.
Build quality is good on both, the Que come with a better stock cable and a wider tips’ selection while the Klean provide for better isolation and comfort.

Kefine Klean vs Truthear HEXA
Completely different sound approach: respectively U-shaped and fun-oriented vs neutral and analytical.
The Klean have more bass and sub-bass, with better punch and note weight, the lower midrange is a bit more recessed than on the Hexa and the upper mids are slightly more controlled than on Truthear’s set. The Klean are slightly more natural and vivid up-top even though the Hexa carry some more informations. Overall the Hexa are slightly more analytical sounding and more sterile, whereas the Klean are still quite competent while never sounding boring or sterile at all.
Imaging is good on both sets, stage is a bit more spacious on the Klean.
The build quality of the Klean feels superior even though the Hexa are built very well too. Klean’s stock cable is better. Comfort is good on both sets, whereas the isolation is a bit better on the Hexa.

Final Thoughts

The Klean are well-rounded and competent IEMs, and they are actually what the Delci would have been if Kefine had applied a few refinements before releasing them. But this is not a bad news, and instead really shows how Kefine has listened to reviewers and users in order to improve a product that already offered a lot for the asking price.
It’s hard to go wrong with a well-tuned set like the Klean, and the price is spot-on for what you receive (except for the fact that I would have liked to see a few more tips in the box).

Another strike (more like a spare in this case, since they had already done a good work with the Delci) from Kefine, hopefully they’ll keep working like this.