With K For Clean

Ratings

Pros

• Very musical sound.
• Two very pleasant, homogeneous and balanced tunings.
• Without any revolution in frequency response, Kefine seems to get the best out of the 10mm DD with DLC diaphragm.
• Excellent construction, simple and durable.
• Remarkable cable.
• Good technical level for the price.
• Ergonomics.

Cons

• Not for those looking for alternative tunings.
• Single set of tips.
• Black mouthpieces may present a slightly more sibilant sound.

Purchase Link

https://es.aliexpress.com/item/1005007957993609.html

Link to the Store

https://es.aliexpress.com/store/1103185504

Introduction

The Kefine Klean is the fourth IEMS of the brand and the cheapest model to date. But that does not mean a drop in quality in any respect. The capsules are made of metal and are manufactured by alloy casting. The inner and outer face of the capsules are secured by means of a screw, which eliminates the need for adhesives that can peel off over time. The dynamic driver has a neodymium magnet and the 10 mm diaphragm is made of DLC (diamond-like carbon), one of the hardest materials in the world. The structure is double-cavity. They come with two sets of interchangeable threaded mouthpieces to provide slight changes in tuning: warm and smooth with the silver mouthpiece and brighter, more transparent and higher resolution sound with the black mouthpiece. The wire is made of silver-plated copper wire. Each strand is composed of eighteen wires of 0.06 mm diameter. The cores consist of three strands. The cable is made up of two cores, so there are a total of 108 wires (18x3x2) in the entire cable. The connection interface is the classic and durable 2-pin 0.78 mm connector. Let’s see what Kefine has to offer for only $49.

Specifications

• Driver Type: 10mm dynamic with DLC diaphragm with N52 neodymium magnet.
• Frequency Response: 20Hz-20kHz.
• Sensitivity: 107dB ± 3dB.
• Impedance: 32Ω ± 15%.
• Jack Connector: SE 3.5mm.
• Cartridge Connection Type: 2Pin 0.78mm.
• Cable Length: 1.2m ±0.2m.
• Weight: 10g per side.
• Starting Price: $49.

Packaging

The Kefine Klean comes in a white box with dimensions 108x128x38mm. On the front side there is a real photo of a capsule with the cable. The brand name is in the top left corner and is written in black letters. Below, in the centre, is the model name and a short description. On the back side are the specifications in Chinese and English. Underneath is information about the brand and icons for the certifications it meets. Underneath the cardboard is a black box with a cardboard flap of the same colour with the brand’s lettering in the centre, written in silver ink. When the flap is removed, the capsules can be seen in a foam mould lined with black cardboard. Underneath is a box with accessories. The complete contents are as follows:

• The two Kefine Klean capsules.
• A grey zippered case.
• One two-strand cable with silver-plated copper wires.
• Three pairs of black silicone tips sizes SxMxL.
• Two pairs of screw-on tips (black grid and silver grid).
• User’s manual.
• Warranty certificate.

Only one set of silicone tips, but the cable is good for the price. Includes two pairs of tuning mouthpieces and a branded zipped case. Kefine has focused on offering a very good quality construction, with a cable that doesn’t need to be changed and a grey case that is very practical.

Construction and Design

The black capsules of the Kefine Klean are made of alloy castings. The outer and inner sides are screwed together. They have a very irregular hexagonal shape, with two longer opposing sides and the rest of the faces smaller to round off the shape. On the outer face is a light-grey rectangular pattern. In the centre, the mark can be read in large white letters. The inner face is smooth and soft, without too many curves, beyond the elevation of the nozzles. There is a Torx screw near the edge. Above it is a white lettering indicating the channel. There are two holes, one next to each letter and one near the nozzles. The nozzle tubes are gold-plated and have a diameter of 5.2mm. The filters have a serrated edge and a diameter of approximately 6.5mm. The 0.78mm 2-pin connection is fully integrated into the capsule.
The cable has two cores, three strands and 18 wires per strand for a total of 108 wires. It is silver plated. The sleeve of the 3.5 mm SE connector is metallic and black, and the brand name is written on it in white letters lengthwise. There is a pair of circular grooves near the cable outlet, which is protected by black plastic. The splitter piece is a black metal cylinder with the model name in white letters. It is narrower at the edge. The pin is a black metal ring with a hole inside. It fulfils its fitting function very well. The sleeves of the 2-pin 0.78 mm connectors are black metal cylinders with the channel lettering in white ink. The cable has ear guides.
The construction is very good, the capsules are very solid and have that security screw. It might weigh a bit more, 10 grams per capsule, but the shape is very good.
The design is not bad at all, not too complex from an ergonomic point of view, but the flat shapes adapt well to the morphology of my ears. I like the sober black with few details.
The cable is very good for the price, it is of good thickness and relatively handy.
The nozzles deserve a special mention, as only the crowns are the filters. They are screw-on and have a coarse, obvious toothing that allows them to be replaced very easily and safely with your fingers.

Adjustment and Ergonomics

The domes are of medium size and their flat-sided shape with rounded corners integrates very well into the pinna. They fit flat, while the mouthpieces are somewhat short and insertion can be only shallow, though somewhat deeper if more suitable tips are used.
Although each dome weighs 10g, the good fit does not compromise on ergonomics. The capsules do not move in the pinna and the fit is unique, durable and occlusive, providing a high level of isolation.
The hardness, fit and comfort make them suitable for everyday use, for outdoor use and for light sports such as brisk walking.

Sound

Profile

Kefine Klean IEMs are inexpensive IEMs with two tuning mouthpieces. According to the brand, the silver-plated mouthpiece offers a warm and smooth sound, while the black mouthpiece provides a higher resolution, brighter and more transparent sound. In my opinion, there are many models with a similar tuning to the Klean with the silver-plated mouthpiece. I would choose the silver-plated mouthpiece for long listens. It is a tiny U or W profile, with very rounded curves and no peaks. The profile achieved with the black mouthpieces is doubly excited in the upper mids and first treble, adding more energy in the 2.5 kHz and also in the 5 kHz. The latter peak can be somewhat more aggressive in an area where the human ear is quite sensitive. Therefore, any excess in this area can be detrimental. As the silver mouthpiece profile is the safest, I have preferred to use the black mouthpiece for this review, as it is more critical and daring.

Bass

There is no doubt that dynamic drivers with a DLC diaphragm can reproduce bass with great power. Thanks to the high hardness of the material, the bass is precise, natural and deep. This is how the bass of the Kefine Klean can be described. Starting with the very low-frequency pure tone test, the 20 Hz sound really natural, with a strong sensory component and hardly any oscillating character, which makes them very pure and very realistic. The fact that the first note starts off so well only presages a great bass range. As the frequencies climb, you continue to perceive very little colour and more energy, and maintain that great physical substrate, while increasing the volume and space occupied. The result is a deep, dark bass, physical and sensory, with power, but without being predominant in the mix. Of course, the DLC diaphragm allows the bases to be very compact and dry, as well as generating very concise, tight and fast decaying hits. The execution of the bass drums is fast, with no aftertaste, not too elastic, just enough, and here we can appreciate that the mid bass is very restrained: it exists in the right proportion to provide volume and strength, but avoiding bleeding into the mids. Undoubtedly, the presence of the bass is more prominent with silver mouthpieces, but it is more compensated with black mouthpieces.
In my classic test of dirty, complex and unfiltered bass, the Klean’s hold up very well, as if reproducing the worst bass was a piece of cake. The speed and precision of the driver allow the bass lines to be very clean, quite deep and well marked. The worst situations are under control and I could only criticise some symptoms of reduction to a simpler reproduction. But perhaps this is the result of how well the Klean’s work in these situations. There’s no stress, the driver doesn’t suffer and that shows in a natural, maybe not too rich, but very successful performance, layering the layers very well and separating the complex lines of the bass drums in a clear and concise way. It’s hard to believe that a $50 bass sounds so effective and realistic.

Mids

As usual in this type of tuning, with a rather technical bass, the first half of the mids is perceived as quite clean. With silver mouthpieces, this part is warmer and denser. With the black mouthpieces, a little more of the base is lost in favour of the middle and upper frequencies. The male voices lack some body and physicality. Overall, they feel quite close in the mix, but without that density that makes them fuller and deeper. As a result, this first half feels leaner, a little thin, though with good presence and cleanliness. It is not a very busy phase and feels freer and more transparent. The energy level of the second half helps a lot. Although it is true that it can slightly favour sibilance, it is not a completely splashy profile, but with a point of vivacity and sought-after expressiveness, but not overdone or too excited. Thus, already in the male voices, one can appreciate how the higher parts are favoured and the accent is placed on the ending of the notes.
The timbre, although natural, is subtly deviated towards brightness, but without losing the neutrality that distances it from the new, darker META curve.
The female vocals are in their element. Although I still notice a certain lack of strength in their base, the rest of the way through until they are fully executed sounds very good. It’s not a display of nuance and resolution, but there is a clear desire to sound quite full, without falling into an analytical profile or losing smoothness or control. I think Kefine wanted to bring the two sides of the Klean midrange sound through the two mouthpieces it comes with: on the one hand, that softer, smoother and rounder sound, warmer and more suitable for long hours of listening. On the other, a slightly sharper, richer and more exposed sound, with the risk that this entails, but without pushing it to the limit, just adding a little more sparkle, light and spice to the upper mids and first treble. This is how the Klean’s upper zone develops, with that brighter aspect, but with a mixture of subtle warmth and sparkle, which is not polarised, but well blended. In this way, the upper mids don’t feel splashy or forced, but maintain a good balance with the black mouthpieces, ideal for those looking for an extra point of clarity and accentuation of detail.

Treble

The Klean’s treble starts with a good initial sparkle, with a slightly elevated, but very well controlled energy level. The result is a punchy base followed by a control zone that stretches into the air zone in a very remarkable way. All this gives the high notes a very natural and full sound, but without stridency. Once again, Kefine has sought to reach the border between musicality and excitement. And I think they have succeeded. Its treble is not only maintained in power and control, but even stretches noticeably into the air zone, maintaining a level of representation that makes the high notes have a good, quite realistic timbre, while the harmonics do not become artificial. Again, it is a commendable effort for a $50 IEMS to achieve a level of finesse and delicacy within a balanced and fairly even smoothness. And all this with a simple dynamic driver. There is a certain punch and a slight crunch that gives authority to the treble, but always within a coherence and order. And I think that’s not easy to achieve. I could conclude that the treble is sparkling, relatively thin and delicate, but always within a controlled and well extended range.

Soundstage, Separation

The Klean’s scene is relatively large on all three axes, filling a space larger than a quarter sphere. There is a sense of roundness in the volume generated, with very good laterality, remarkable depth and that point of height that elevates the notes and gives them a certain enveloping sparkle. However, it is not extraordinary in this respect. But it is quite clean and transparent. But, above all, it is orderly and coherent, and maintains musicality as its main premise. With the black mouthpieces it is cleaner and more transparent, and it gains the impression of incipient micro detail, quite well achieved for an ensemble that does not seek to be analytical. I feel subtle nuances subtly expressed with considerable ease and clarity. Reaching this point is already a great achievement, especially considering the price and without looking for technicality above all else. The Kleans have enough sharpness and resolution to show that good level of detail, while maintaining a coherence and balance in their more fun and sedate presentation. So, once again, you have to appreciate the resolution of a $50 driver and the tuning that powers it.
The image is coherent, well presented, with a logical and realistic positioning of the elements, without artifice or showiness. It is rather a solvent and successful image.
The separation is noticeable and there is a slight darkness in the background. You can dig into it and discern that small detail, not too sharp or delimited, but there it is. And much better than in more expensive sets. Not bad at all.

Comparisons

KZ ZS10 Pro 2 1111

The KZ ZS10 Pro 2 cost $56 and have 5 drivers (1DD + 4BA). They are made of a hybrid construction with resin on the inner side and a metal panel. They have four tuning switches instead of interchangeable mouthpieces. The packaging is minimal and includes a single cable. The Klean Kefine Klean surpasses them in construction, design, presentation and accessories, and is less expensive.
The capsules of the KZ are thicker and, although their ergonomics are not bad, the comfort and fit of the Klean is clearly superior.
In terms of profile, the KZs can be tuned to different degrees of bass. But with all switches in the ON position, the frequency response more closely resembles an excited, rising W. The Kleans with the black mouthpieces have a W-shaped profile, but softer in the treble. It is worth noting that the curve is very similar up to 1000 Hz.
The Klean’s are a little easier to move and, for the same power, sound louder.
I already commented in the review of the KZs that their bass was good, dark and deep, but with a medium speed. The Klean’s bass has a superior punch, punchiness, texture, speed and technical quality. It is not so dark as to become dull, but it is better behaved. In the very low frequency pure tone test, the Klean’s are subtly more physical and less coloured, as their wave character is lower, giving them a more realistic and natural response.
In the middle range, the first half is warmer and denser in the Klean. The male voices have more body, presence and a more accurate timbre. In the KZ, everything is leaner, with a point of imbalance and a more pronounced V-feel. The Kleans have a more homogeneous character, are more pleasant and musical.
There is also a more pronounced thickness in the female voices, which sound fuller and more realistic. The KZs, on the other hand, have a somewhat more synthetic sonority, comparatively speaking.
In the treble, the Kleans have an explosive start, but their energy level decreases afterwards. The opposite is true of the KZs: they are controlled and smooth at first, but then fill out in the mid-range. This gives them a somewhat strange and less natural timbre, which also adds to the behaviour of their BA drivers, which are further away from the realistic and organic sound of the Klean.
The KZs may boast more drivers, but the Kleans gain in micro-detail, clarity, resolution, balance and musicality. The sound is crisper, while the KZs are more muted and nuanced, with details omitted in comparison. The soundstage is superior, the sound is more open and transparent, and separation is more clearly perceived. The Kleans, with one driver, do better than the KZs with five.

Conclusion

The young Kefine brand is also demonstrating its know-how in the $50 segment. Without any revolution, playing it safe, but offering a very musical and expert tuning, something that is already a hallmark of the brand itself. The Kefine Klean is a reliable bet for those who want a tremendously musical IEMS with a bit more of everything, including good technical skill. With excellent die-cast metal construction, screw-secured capsules, a quality cable that avoids having to buy a new one, and two pairs of mouthpieces to change the tuning: warm and smooth with the silver mouthpiece; brighter, more transparent and higher resolution sound with the black mouthpiece. The Klean can easily become a fully recommendable set as an all-rounder, for everyday use as well as for leisurely and enjoyable listening.

Sources Used During the Analysis

• iFi GO bar Kensei.
• EPZ TP35.
• Tempotec V3.
• Burson Audio Playmate 2.
• Aune X8 XVIII Magic DAC + EarMen ST-Amp.