Double Action

Ratings

Pros

• Bass with weight, body, punch, physicality, volume, and texture.
• Mids that move between the warm, physical density of the black filter and the liveliness and sparkle of the gold filter.
• Crisp, energetic, and well-extended treble, but without crossing the line.
• Volumetric soundstage.
• Good level of detail, technical skill and resolution even with the black nozzles.
• Excellent level of accessories, thick and modular cable, zippered case and four sets of silicone tips in two plastic cases.

Cons

• The bass frequencies have a medium decay and are evident throughout the rest of the frequency range.
• Sharp BA character in the treble and upper midrange.

Purchase Link

https://hifigo.com/products/kefine-quatio
https://www.aliexpress.com/item/1005009240353190.html
https://www.amazon.com/dp/B0FBWGD472?th=1
https://www.amazon.co.jp/dp/B0FBGGQBH3

Link to the WEB

http://www.kefineelec.com/en/

Introduction

KEFINE, the brand name combining the founder’s name Ke and the word ‘refine’, aims to offer refined audio products for music lovers at an affordable price and with the best value for money. On this occasion, the brand has launched a new hybrid product, the first of its kind, consisting of four drivers (2DD+2BA) and named Kefine Quatio. Each capsule houses a 10mm driver with a DLC diaphragm, which produces a high-resolution response across the entire frequency band, and an 8mm driver with a PU+LCP diaphragm, which has been positioned to improve bass response. The dual BA configuration is tasked with delivering an enhanced high-frequency band above the 5 kHz frequency range. Together, these four drivers, combined with the precise crossover design, ensure the highest quality sound presentation. Kefine Quatio features a three-way crossover design. It is a hybrid crossover design comprising both physical acoustic tubes and an electronic crossover board. There are three acoustic channels, each of which goes directly from a 10mm, 8mm and dual BA configuration to the ear nozzle. The sound is warm, rich and musical. They have three replaceable tuning nozzles: a gold nozzle for a transparent, neutral and more accurate sound, a silver nozzle for a balanced sound profile, and a black nozzle for a warm and smooth sound response.
The pair features exclusive CNC-machined aluminium alloy ear cavities. The processing time for each pair of shells is over 30 minutes, and the dimensional tolerance is 0.01 mm. Each pair has a highly textured finish, as they have undergone advanced polishing and anodising processes. The thickness of the Quatio metal shell is only 0.06 mm, which minimises the size of the shell and ensures a comfortable fit for most users.
Kefine Quatio includes a high-purity silver-plated oxygen-free copper cable. It is a 4-wire cable with a braided structure. Each strand contains 98 wires, for a total of 392 wire cores. It guarantees lossless sound signal transmission. This cable features an interchangeable connector system with 3.5 mm and 4.4 mm connectors included in the package.
Finally, the set comes with 4 sets of silicone tips distributed in two dedicated cases that still allow the user to tune the sound to their liking.
Let’s see what this new Kefine model has to offer.

Specifications

• Driver Type: 10mm 1DD with DLC diaphragm + 8mm 1DD with PU+LCP diaphragm + 2BA.
• Frequency Response: 20Hz – 20kHz.
• Sensitivity: 107dB±3dB.
• Impedance: 32Ω.
• Jack Connector: Modular cable with interchangeable 3.5mm SE and 4.4mm BAL plugs.
• Capsule Connection Type: 2Pin 0.78mm.
• Cable Length: 1.2m.
• Starting Price: 129.99$.

Packaging

The Kefine Quatio comes in a medium-sized black box measuring 142x119x65mm. On the front is a real photo of a capsule with its cable and a silicone tip. In the upper left corner is the brand name and at the bottom is the model name and a description of the drivers, mainly in white ink. The back is divided into two boxes, the first containing the specifications in two languages. The second contains the brand’s logo. After removing the cardboard, a black box with the brand name in silver ink in the centre is revealed. Under the lid there are two sections, the upper one containing a foam mould lined with black cardboard and containing the two capsules. The lower part is larger and is a black cardboard box. Underneath and inside are the manuals and other accessories. In summary:

• The two Kefine Quatio capsules.
• User manual.
• Quality certificate.
• Instructions for the mouthpieces.
• A black faux leather case with zip.
• A transparent plastic box with two sets of white silicone tips.
• A transparent plastic box with two sets of black silicone tips.
• A modular cable with interchangeable 3.5 mm SE and 4.4 mm BAL plugs.
• Three pairs of interchangeable tuning nozzles (one installed in the capsules).

What you get for 130$ is pretty good: a nice case, a rather attractive modular cable, four sets of silicone tips stored in two plastic cases, and three sets of tuning nozzles. That’s pretty good.

Construction and Design

The Kefine Quatio capsules are not the most original in design, but they are well constructed. They are metallic and manufactured using CNC technology. The outer face of the capsules is oval-shaped with a thinner vertex at the bottom. Near the edge there is a groove that surrounds the entire capsule, and the interior is light grey. The same incision and ink has been used to put the brand name in the centre of the face. The capsule’s connection interface is integrated into the surface. The 2-pin 0.78 mm contacts are gold-plated. Nearby is a white letter indicating the channel. There is a hole in the curve of the edge. The inner face is very rounded and smooth, with no protrusions. The surface is matte, micro-textured. The interchangeable metal nozzles are mounted on an oriented, stylised base. The nozzles are 4.2mm long, with a lower diameter of 5.5mm and an outer crown diameter of 6.4mm. The metal grille has a spiral pattern and is colour-coded to distinguish each pair: gold, black and silver.
The cable consists of four thick intertwined strands. Its colour is a dark silver champagne. The plugs are interchangeable using a screw mechanism. The cable entry to the plug housing is protected by a tight-fitting plastic cover. The upper part of the sleeve is a larger diameter crown with a triangle to indicate the position of the part containing the plug. The next part is a knurled crown with an internal thread necessary to attach the cylinder containing the plug. This part has another triangle to aid attachment and the brand name. The part of the cover that contains the cable is the male part and has four gold-plated pins. The plug part is the female part and its connectors are also gold-plated. They are mounted on a male plastic base with a slot, while the four pins protrude from a female base with a guide to secure the assembly. The splitter piece is a cylinder with thin edges and a larger diameter. The model name is written lengthwise in white letters. The pin is a metal ring that does its job very well as it is difficult to move. The 2-pin connector covers are cylinders with the channel letter in white ink on each one. The two pins are mounted on a piece of translucent white plastic. All parts of the cable are metal, with a dark champagne gold colour to match the cable itself. The cable has a black Velcro strap. The strands are subtly rigid so as not to bend, but they are soft to the touch and do not offer much resistance to bending, being consistent and pleasant.
As I said, the construction of the capsules is nothing new in terms of design, but their build quality is impeccable. The modular cable, while not spectacular, is very well designed and I think it adds great value to the set and is perfectly adequate without needing to be replaced by others.

Adjustment and Ergonomics

A simple, well-proven design offers proven ergonomics. The surface of the capsule is matte and micro-textured, very soft and pleasant. The inner surface is completely rounded and has no protrusions. This makes the fit somewhat looser and allows for slight rotation within the ear canal. The best position is when the capsule cannot rotate any further. This point seems to achieve the best angle for the nozzles in relation to my ear canal. So I think you need to play around with this rotation and the best set of silicone tips you can find to ensure a shallow but occlusive and firm insertion. And, as usual, I achieve this with my large silicone tips filled with foam by hand. Although the fit is quite firm, it is not the most durable I have been able to achieve. What is certain is that the capsules do not touch any external part of my ears. The isolation is not the best, but it is noticeable. The result is quite comfortable because it does not cause discomfort over long periods of time. It is recommended for gentle, everyday use, but with some care. I do not recommend it for running or more vigorous exercise.

Sound

Profile

The Kefine Quatio features three pairs of tuning nozzles that allow you to modify the frequency response. The default nozzle is the silver nozzle and has a U-shaped or lowercase W profile. This is certainly not an unusual profile for the brand, as the Kefine Klean, also with its Silver filter, has a very similar FR, but more rounded. The Quatio Silver offers less air and a slightly more abrupt profile. There are many models with this profile: Apevoix Grit, Hidizs MP145, KiiBOOM Evoke, Kiwi Ears Astral, LetShuoer S12 Pro, NiceHCK F1 Pro, Tri Meteor, etc. The black nozzle subtly softens the upper mids and early highs and slightly emphasises the sub-bass. Despite this, a better balance between the mids is achieved. With the silver nozzles, the first half of the mids sound somewhat more disconnected and distant. The greater bass extension of the black nozzles gives more body to the first half of the midrange, and the decrease in energy in the second half balances the central range, making it more homogeneous and linear. With the gold nozzle, it is just the opposite, with a slight decrease in the sub-bass and greater emphasis on the upper midrange and early treble. With these nozzles, the sound pressure increases and the sound becomes clearly more lively and vivid, but also more aggressive and sharp. It is clear that clarity is gained, but it becomes less musical and more sharp, focused on macro detail and edges.
It is clear that the profile with the black nozzles is the closest to a profile suitable for bass-heads, but it is also a more balanced profile in the midrange, and that is something I value highly. The sound impressions expressed below were made using the black nozzles.

Bass

The Kefine Quatio with black nozzles has extended bass, which starts powerfully from the sub-bass. It should be noted that the Quatio has two dynamic drivers, a 10 mm driver with full bandwidth and an 8 mm dynamic driver that serves as bass reinforcement. Each of them is connected to the nozzle by means of an individual tube, and the dual BA driver and sound are also connected by an electronic frequency divider. This results in powerful, clean bass, free of artefacts from the BA drivers. This is demonstrated in the very low frequency pure tone test. The first tone is dark and sensory, with a slight undulating character, not very pronounced but perceptible. The physical sensation is remarkable, enhancing the natural and deep character of the bass. As the frequencies increase, the undulating character disappears and the physical component is amplified, while the audible bass becomes more noticeable. The translation of these results to real music implies a relatively deep bass, but not too dark, with a good physical and sensory component that lingers in the environment, while the decay speed is faster for the mid-bass. This generates a moderately elastic but controlled bass, with a very pleasant rubbery expansion, which is noticeable in the atmosphere but is round, well defined, collected and sufficiently dry and compact. Good control and technical skill ensure that the decay is not excessive and that they feel fast enough to be agile and with a delicate texture that is not too pronounced, on the soft side of things. The remarkable sensory character manages to raise the volume occupied, something that is enhanced by the use of black nozzles. The punch is more physical and, similarly, the sensation of depth expands in length, accentuating the voluminous character of the bass. The size generated by the sub-bass, supported by the presence of the mid-bass, achieves an orientation close to the Bass-Heads terrain, which is very appealing and fun, but should be taken into account by those looking for a more neutral bass. It is true that the nozzles reduce this presence, but its potential greatness remains.
In the dirty, complex, unfiltered bass test, that deep, semi-dark, sensory character prevails. The lower bass lines are executed with good control, with a certain roughness generated by the struggle between control and the physical capacity of the dynamic drivers. These are not the smoothest lines, and there is a more vigorous, marked and muscular power, but it is sufficiently contained so that control is not lost. The higher bass notes remain more contained, while the lines and layers with fewer hertz are those that are composed of a more raw physical and sensory component. Despite any sensations, the Quatio is convincing and turns that physical capacity into an attraction on the edge of the abyss, which never overflows. This means that there is enough control to separate the complex layers from the dirty lines, demonstrating remarkable technical skill in resolution and detail in the bass.

Mids

The volume, power and grandeur of the bass can take up part of the space dedicated to the mids, especially if the bass is heavy and noticeable. In more balanced compositions, the tuning generated with the black mouthpieces favours warmer male voices, but with a fuller base and slightly more body. The imbalance between the first half of the midrange and the upper range is balanced, resulting in a more homogeneous midrange, with more physicality, thickness and a less splattered and vivid feel, thus making the result less sibilant and more natural. A good sense of transparency and clarity is maintained, always from a warmer and fuller perspective. The midrange has a good level of resolution, which does not feel nuanced or softened. In this way, the sensation of detail, clarity, separation and brightness remains despite the use of the black mouthpiece. It is by no means a monster of detail, nor is it an analytical sound, but despite the volume and presence of the bass, the nuances are easy to distinguish, offering an incipient micro detail that does not require much scrutiny of the sound to find.
The first half of the midrange is by no means overwhelming, but it does have a consistency and weight of its own that avoids my hated hollows and dips. This is how the male voices present a complete force from the base, with decisive nuances adapted with great naturalness and realism. The colour is pleasant, the brightness sufficient, while the voices thin out appropriately towards the details, reflecting a well-executed first part of the midrange, without losing sight of a very complete and equally full instrumental representation.
The use of silver and gold mouthpieces thins out male voices, making details more apparent, while the mids become more articulate and agile, but also thinner. There is some inconsistency between the bass and the first half of the mids, a certain hollowness or dip that is resolved with the black mouthpiece. It is true that the level of transparency, the appearance of the treble, as well as the feeling of clarity, brightness and separation is greater with these silver and gold mouthpieces. But I still think that the musicality I get with the black mouthpieces compensates for this.
The second half of the midrange remains relatively thick, with a subdued brightness, allowing you to continue enjoying the warmth and smoothness of female voices. Those looking for a more tactile, incisive and pronounced result should use the silver and gold nozzles. But I, having analysed several IEMS that feel soft in this upper midrange, prefer to maintain control and a more mature, musical and pleasant tuning, prolonging the idyll between musicality, informative and expressive capacity. And it is certainly true that the Quatio achieves a good pinch of that feeling for much less money.

Treble

The treble with the black filter has a good initial spark that is sustained, but its execution is slightly abrupt. It is clear that the mixed BA and DD treble is powerful, crisp and pronounced. But don’t expect the refinement you would find in higher-priced models. You can feel that slight BA character, with a more incisive and piercing brightness, which stands out with a sharper presentation. But there is also a noticeable extension into the airy zone, creating that volatile feeling in the environment before its clear decay above 10 kHz. The strength and sparkle demonstrated up to this point is projected further, producing a more perceptible sense of extension. This, combined with a measured but balanced amount of energy, produces sharp, homogeneous and exciting treble depending on the mouthpiece chosen.

Soundstage, Separation

The great volume and depth achieved by the bass makes the soundstage seem relatively large. The width is good, with a good level of laterality and average height. Depending on the mouthpieces used, you can feel more volume (black mouthpiece) or a more volatile sensation (silver or gold mouthpieces). The level of transparency, brightness, sense of openness, holographic impression, separation and clarity is also improved from the black nozzle to the gold nozzle. While the sense of detail with the black nozzle is flatter and more natural, the depth and volume are greater.
The image is precise, the positioning is smoother with the black nozzle and stricter with the rest.
The resolution and micro detail also depend on the mouthpiece. It becomes more analytical with the silver and gold mouthpieces, but I don’t feel more natural with the black mouthpieces. The micro detail with the dark mouthpiece allows you to feel the micro detail in an incipient way, and thanks to the good performance in generating sound layers and separating them, these minute details can be observed in a relatively visible, subtly appreciable way.

Comparisons

Kiwi Ears Airoso

With the same starting price and a driver configuration of 1 DD with LCP+PU diaphragm and 4 BA, we have the Kiwi Ears Airoso. This is a fairly recent model, released at the end of the first quarter of 2025. The Airoso comes with the classic Kiwi Ears case and a fairly thin cable compared to the Quatio cable. It is not even modular and is only available in a 3.5mm SE version. The Airoso comes with 3 sets of silicone tips, while the Quatio comes with 4 sets in two plastic cases. In addition, the Quatio comes with three pairs of tuning nozzles. It is clear that Kefine is superior in terms of accessories.
The design of the Airoso is unremarkable and its exterior plate is quite bland. It’s not that the Quatio is a masterpiece of design, but its metal construction is a plus. However, it’s clear that the ergonomics of the Airoso are a strong point; they fit me like a glove that doesn’t want to leave my ears. The clean, smooth design of the Quatio is somewhat smoother, and you can feel the extra weight and size.
The following comparison will be made with the black nozzles of the Quatio.
The Kefine Quatio are more sensitive; with the same amount of voltage, they sound louder.
The comparison graph shows that the profile of both is quite similar. The sub-bass is not as high in the Airoso, but they practically overlap between 100Hz and 5kHz, with the Kiwi being more homogeneous and smooth in its curve. The treble moves at a similar average but with different ups and downs. Then, the greater number of drivers means that the Airoso has more air.
The bass on the Airoso is slightly faster, has less volume, is slightly smoother and has less texture. There is more power, weight and punch in the bass on the Quatio, as well as more depth and physical and sensory capacity, but its decay and resonance is superior, although its texture is more noticeable.
In the very low frequency pure tone test, it is noticeable that the Airoso are technical, with very good performance and a very balanced relationship between physicality, sensory capacity and sound. The Quatio are darker, with lower sound and greater physical and sensory capacity. As the frequencies increase, the Airoso gains ground in terms of physicality, and both the loudness and physicality and performance become very similar between the two IEMS.
In the dirty, complex, unfiltered bass test, the Airoso proves to be more precise and decisive. On the other hand, the Quatio demonstrate greater depth, darkness, volume, punch and weight, but they are also noticeably slower and linger longer in the environment.
In a midrange with such a striking similarity in the frequency response curve, the differences are based more on individual auditory perception. The midrange of the Airoso is subtly brighter, while the Quatio with black nozzles is denser, fuller and darker. Male voices are slightly closer to the listener in the Airoso and seem more dynamic. There is more weight and physicality in the Quatio, and a slightly slower movement.
The upper midrange of the Airoso has more sparkle and liveliness than the Quatio Black. The Quatio Black’s greater physicality persists in this second half of the midrange, generating a fuller, more physical and warmer sound. The Airoso seems more decisive and refined, with slightly more speed in the central range. The disadvantage is that the Quatio have two pairs of nozzles to excite the midrange, something that the Airoso do not have.
The Quatio Black’s treble is more sparkling, crisper, better measured in its energy extension and sharper in sound. The Airoso tends to be a little softer, rounder and more controlled, but flatter in its energy level and with a more nuanced edge, yet it has more air and extension above 10kHz.
The soundstage is more voluminous in the Kefine Quatio Black in its lower range, but overall the soundstage is larger, more expansive and three-dimensional in the Airoso. The Kiwi also has less density and gives the impression of better separation and distance between elements. However, the level of resolution is very similar between the two models, allowing you to scrutinise micro details at almost the same level. Only that feeling of more air, a more separated and darker background seems to generate a slight difference in distance in the micro detail. But it is not a generic rule. The Quatio has nozzles that can improve technical performance at the expense of moving away from this smoother, warmer profile.
In general terms, the Kefine Quatio is more versatile due to its nozzles, with very similar performance and very good accessories that enhance the quality/price ratio.

Conclusion

Kefine is moving forward steadily and launching its first 2DD+2BA hybrid at a price of $130, offering great value for money thanks to its sound quality, build quality and the excellent set of accessories that come with it (zippered case, three sets of tuning nozzles, thick modular cable with two 3.5mm SE and 4.4mm BAL plugs, and four pairs of silicone tips distributed in two plastic cases). Its dual DD achieves a great, synchronised and reinforced bass response, with a great physical component, weight and punch, bordering on Bass-Heads level. The treble is crisp and sharp, expressive, informative and extensive. The midrange moves between the dense, musical warmth of the black filter to become thinner, more dynamic, expressive, marked, sparkling, sprinkled and vivid with the silver and gold nozzles. Without a doubt, this is a very versatile model with remarkable sound quality, well worth considering in the 100-150$ range.

Sources Used During the Analysis

• iFi GO bar Kensei.
• EPZ TP50.
• Burson Audio Playmate 2.
• Aune X8 XVIII Magic DAC + OpAmp Sparkos Labs SS3602 + ifi ZEN CAN 3.
• Tempotec MARCH V.
• Tempotec V3 Blaze.