In today’s review, I’m checking out the Kefine Quatio IEMs. Quatio is a quad-driver in-ear monitor with 2 dynamic drivers and 2 balanced armatures, and 3 distinct sound profiles. It’s priced at 129 USD.
Disclaimer: This sample was provided by KEFINE in exchange for an honest review. All observations and opinions here are my own, based on my experience with the product.
KEFINE Quatio
Specifications
Driver Type: 2 DD + 2 BA
Driver Sizes: 10 mm & 8 mm
Frequency Response: 20 Hz – 20 kHz
Sensitivity: 107 ± 3 dB
Impedance: 32 Ω
Cable Length: 1.2 m ± 0.2 m
Plug Types: 3.5 mm SE & 4.4 mm BA
Inside the Box
- Quatio earphones x1
- Hard carrying case x1
- Tuning nozzles x3 pairs
- Eartips (L/M/S) x12 pairs
- User manual x1
- Quality certificate x1
- Notice card for nozzles x1
- Eartip storage case x2
Design
The Kefine Quatio doesn’t go out of its way to impress you with a flashy exterior. On the contrary, it’s rather utilitarian with its matte black aluminium shells and plain black faceplates with just some KEFINE branding in the middle. The surface feels tough and resists fingerprints, which keeps them looking fresh – a nice change from the polished fingerprint magnets that some IEMs have!
Despite having only a single pinhole vent behind the 2-pin sockets, I don’t feel any unpleasant “cabin pressure” while using the Quatio. The nozzles, which also act as tuning filters, are precisely machined and easy to swap out.
Sound
Sources used for testing include the SMSL RAW-MDA1, iBasso DX180 and Cayin RU6. The Quatio is an efficient IEM and doesn’t have demanding power requirements, so you can use it with any audio source.
The fun is back! For a while, it felt like both manufacturers and enthusiasts were fixated on flat sound signatures or the usual “neutral with a sub-bass boost” tuning. Those of us who’ve been around longer (say, 6+ years) might remember when bass was celebrated—ChiFi brands used to flaunt “Fever Bass!” in their marketing. Back then, it was a bit like the wild west—anything could happen. I’m digressing a bit here, but my point is: KEFINE has consistently focused on musical, well-balanced tunings, and it’s paid off. The Quatio continues that approach—designed for enjoying music, not just impressing with graphs.
I’m not saying the Kefine Quatio is a bass monster—far from it. But it has some character and a fullness that makes it both engaging and non-fatiguing. It balances body and technical performance to give you the best of both worlds. Those who prefer absolute transparency and no colouration should seek alternatives, but people who are looking for something with a musical flavour—whether it’s a bit of warmth, punch, or nuanced emotion—will likely find the Quatio hits the sweet spot. It’s lively enough to bring energy and dynamics, yet refined enough to keep vocals, instruments, and detail firmly in focus.
A Word on Filters
The three tuning filters adjust the amount of bass and lower midrange. The black filter is the warmest and smoothest, increasing the bass and adding thickness along with some extra thump to kick drums. The silver filter sits in the middle and delivers the most balanced sound, while the gold filter has the least bass and, as a result, gives the impression of more perceived treble. The silver filter resonated most with my ears, so that’s what I’ll be focusing on for this review.
Bass
Quatio’s bass is well-controlled but also knows how to let its proverbial hair down and have some fun. Sub-bass notes reach deep with satisfying impact, but without lingering or becoming overbearing. The lows feel authoritative and integrated—part of the overall tuning, not just an afterthought added to prop up an otherwise anaemic or overly analytical presentation.
The mid-bass is slightly tamer but still delivers plenty of punch and slam to drive the music along. Notes are well-defined, with a crisp leading edge that gives the bass clarity and precision, all while maintaining a strong rhythmic presence.
Midrange
The midrange of the Quatio hits that sweet spot between warmth and clarity. Male vocals feel full-bodied, bringing natural warmth without sounding thick or bloated, while female vocals retain a crisp edge—delivered with sweetness rather than harshness. Instruments like strings and piano have a pleasing presence and realism, anchored by a clean tone and texture.
What really stands out is how the mids fit seamlessly into the overall tuning. They’re neither too forward nor recessed—they simply sit right, allowing for expressive dynamics without stealing focus. There’s just the right boost in the upper mids to give tracks a touch of energy and life, but it’s never shouty or fatiguing. People who appreciate natural timbre and a balanced vocal performance will find that the Quatio midrange checks all their boxes.
Treble
With a bass-elevated and fun sound signature, a good treble tuning is key to holding things together, and Kefine has nailed it with the Quatio. The treble is smooth and well-mannered, with just enough sparkle to keep things lively without tipping over into harshness. It doesn’t chase ultra-extended highs or overdo the air, but there’s a gentle lift that adds clarity and a sense of space. Cymbals sound crisp but never splashy, and there’s no distracting grain or sharp edges in the upper registers.
It’s the kind of treble that prioritises long-term listenability over trying to impress with exaggerated detail. That’s not to say it lacks resolution—it just delivers it in a more relaxed, unforced way. It sits comfortably in the mix, supporting the rest of the tuning rather than demanding attention, although some might find the gold filters a bit edgy.
Soundstage & Technicalities
To round out the Kefine Quatio’s performance, it presents a large, natural soundstage with well-balanced width and depth. Vocals are placed front and centre, with good note density and stability. There’s a strong sense of layering, and positional cues are precise—even with the natural roundness to the notes. Overall resolution is excellent, supported by clean instrument separation. To top it off, the Quatio is also adept at detail retrieval, picking up minute details while keeping things smooth and fatigue-free.
Comparisons
ArpegEar Hane
The ArpegEar Hane uses a single 10mm dynamic driver, compared to the Quatio’s 2DD+2BA configuration. Its resin shells are lighter and slightly more ergonomic for my ears. In terms of tuning options, the Hane uses four tuning switches, while the Quatio relies on three interchangeable filters.
These two IEMs are quite similar in terms of frequency response. The Hane has slightly less sub-bass, but thanks to the resonance of its resin shells, it still feels very much on par with the Quatio in terms of bass presence. Beyond that, both share a similar tonal balance.
There’s a real cohesiveness and naturalness to the Hane that’s hard to find at this price point, and it pulls slightly ahead of the Quatio in that regard. However, it doesn’t quite match the Kefine Quatio’s instrument separation. Those who are sensitive to treble and sharpness may find the Hane’s percussion more tolerable, while the Quatio’s notes come across more etched and defined.
To my ears, the Hane leans closer to true neutral, while the Quatio carries a bit more colouration. Both offer a similarly spacious soundstage, but the Quatio edges ahead when it comes to imaging precision.
Letshuoer S12 (Original version)
These days, the Letshuoer S12 can often be found for the same price—or even less—than the Quatio, so I thought it would make for an interesting comparison. The S12 uses a single planar magnetic driver, while the Quatio features a 2DD+2BA configuration.
Right off the bat, the S12 sounds leaner and brighter. It has a very etched, analytical character with fast transients and crisp note edges. Sub-bass extension and presence are both reduced compared to the Quatio, but the S12’s bass is tighter and more agile.
The S12’s midrange is shaped by a prominent 2kHz peak, which gives it strong vocal presence and clarity. However, this also makes it prone to harshness or shoutiness, especially when paired with its elevated 8kHz treble peak. Cymbals can sound splashy, whereas they’re smoother and more tolerable on the Kefine Quatio. In contrast, the Quatio’s midrange has more body and note thickness.
In terms of technicalities, the S12 excels at transient speed, bass control, and micro-detail retrieval. But it can also feel less resolving in dense passages, where the upper treble haze blurs separation—something the Quatio handles more gracefully. I’m less taken with the S12 now than I was when I first reviewed it—it’s starting to show its age.
Verdict
The Kefine Quatio is a refreshing reminder that IEMs don’t need to chase clinical neutrality to sound great. With its balanced, musical tuning, solid technical chops, and flexible filter system, it delivers an enjoyable and fatigue-free listen that still holds up under scrutiny. Considering the sonic performance and the generous set of included accessories, including a modular cable, the Quatio offers outstanding, class-leading value. This one raises the bar. Highly recommended.
