• 1DD Driver Configuration;
• Impedance: 32Ω;
• Sensitivity: 107dB;
• Frequency response range: 20Hz-20kHz;
• Connector: 2 pin 0.78mm.;
• Cable material: 2 core silver-plated copper cable;

 WHAT'S IN IT:

• IEM itself;
• 2-core silver-plated copper cable, 1.2m length;
• 1 sets, 3 pairs of regular black eartips: (S / M / L);
• Interchangeable black nozzles;
• Carrying case;
• User manual and quality certificate.

• Price:49$.

 FIRST IMPRESSION

The Kefine Klean shells are made from a metal alloy using a two-part construction method. They feature a matte black finish, giving them a solid and premium feel. Each shell weighs 10 grams without eartips.

The faceplate is adorned with a subtle pattern of lines and squares, accompanied by a large white "Kefine" logo. I believe this design choice fits well in any scenario, whether you're at the office or a party.

The back of the shell includes a brass nozzle that is relatively wide and long (with a silver filter installed by default), a screw that reinforces the structure to prevent the shell from splitting, two compensation vents, and R/L markings.

The side of the shell houses a 2-pin 0.78mm connector.

I have not had any issues with the build quality. All the parts are carefully made and I have not had any complaints about the build.

COMFORT

Kefine designed the Klean shells to be compact and ergonomic, ensuring they fit most ear shapes. The shells are perfectly contoured to the ear, providing a deep and secure fit without causing discomfort, even during extended listening sessions. Despite their relatively substantial weight, the shells do not feel heavy or intrusive in the ears. I find this shape to be universally accommodating and comfortable for users with both large and small ears. The only minor drawback is the metal housing, which feels cold for a short while after putting them on.

Thanks to their snug and deep fit, the Kefine Klean provide about 70–80% isolation from external noise, which is a commendable result. With the right choice of eartips, I can confidently say you’ll be satisfied with the noise isolation these IEMs offer, allowing you to enjoy your music without distraction from outside sounds.

CABLE

The Kefine Klean stock cable is of high quality and feels pleasant to the touch. It’s a 4-core braided silver-plated cable made of oxygen-free copper, enclosed in a PVC sheath for protection against damage and tangling. The cable is lightweight, flexible, and thin, providing a comfortable experience when using the IEMs.

All the fittings on the cable matches the color of the shells, leaving a positive impression. One end features a 3.5mm connector with the Kefine name, the middle section has a metal splitter, and the other end includes ear hooks. However, the ear hooks are somewhat unusual: their shape doesn’t fully wrap around the ear but extends slightly backward due to the straight design rather than a curved one.

This cable reminded me of the ones Simgot provides with their EA500/LM and EM6L models. Overall, it’s a high-quality cable made from premium materials that doesn’t require replacement.

EARTIPS

The stock eartips provided with the Kefine Klean are standard and familiar to most users. They are gray, made of rubber, and have a typical bore. In terms of firmness, they strike a middle ground—neither too soft nor too firm. However, due to their somewhat unusual design, they didn’t fit my ears, even in the smallest size (S).

In terms of sound performance, these eartips offer fairly balanced sound reproduction, without emphasizing any particular frequency, simply complementing the IEMs default tuning. In the end, I decided to use similar tips from BQEYZ.

DRIVABILITY

In terms of sources, I noticed a slight improvement in performance and sound quality when using the Kefine Klean with more powerful sources. During testing, I connected these IEMs to various devices, and switching from a phone to the Fiio KA11, I observed an increase in sound quality: the soundstage became wider, with a sense of air and fullness in the audio.

When connected to the Qudelix 5k, the soundstage expanded even further, and the sound scaled up, gaining additional depth.

SOUND

To summarize, these IEMs perform best with powerful sources, but they also deliver satisfactory performance when used with a phone or tablet.

The Kefine Klean are more U-shaped IEMs rather than V-shaped ones. They offer two sound tuning options depending on the selected nozzle. The main and significant difference between the silver and black nozzles lies in the elevated upper midrange (+3 dB) with the black nozzle, along with slightly altered treble. I used the pre-installed silver nozzles as I find their sound more natural and accurate.

BASS

Since this model features a single dynamic driver, the bass is incredibly captivating and impactful. Let’s break it down:

Sub-bass: Fast, punchy, and resonant, achieved through a well-defined bass impact. The sub-bass delivers a small but palpable thump that energizes the sound and adds fullness to the bass body, making it more defined and complete. It’s fast enough to set the right depth while helping the bass form a dense and rich structure.

Mid-bass: Deep, resonant, and assertive. These IEMs emphasize quality bass over quantity, delivering smooth, buttery mid-bass with a gradual rise and decay, resembling a parabolic curve. The bass is dense and avoids any muddiness, even in bass-heavy scenarios. These are not basshead IEMs, as the focus here is on quality over quantity.

Instruments sound excellent: the bass guitar has an energetic tone, drums are deep, and MIDI controllers and drum machines convey bass-heavy sounds in EDM tracks with precision. For me, listening to rock, EDM, or atmospheric music with these IEMs was pure pleasure.

MIDS

Lower mids: Melodic, soft, and natural. This range delivers a pleasant and full-bodied sound, neither overly bassy nor flat. The lower mids excel at reproducing instruments. The tone of the guitar is natural and authentic, while the saxophone and clarinet have a velvety texture, adding warm and smooth notes to jazz tracks. This range complements and enhances the midrange frequencies, strengthening their performance.

Mids: I believe this set was specifically designed to reproduce a high-quality, mature midrange with Kefine's signature sound. The mids are balanced, neither pushed forward nor recessed. I appreciate how the tone of the Klean adjusts to the character and timbre of voices or instruments, creating a flexible and luxurious sound that is typically found in premium IEMs.

Instruments sound outstanding: the piano is melodic and rich, the guitar is full of energy, and the violin is refined and pleasantly vibrant. I am fully satisfied with the melodiousness and tonal delivery of instruments in the Klean.

Male vocals are impressive and tonally accurate. Accurate tonal reproduction is a key indicator of well-tuned vocal performance. The vocals here are not muffled; I can hear every breath and tonal shift, from high to low. Listening to iconic voices like Sinatra, Jackson, Presley, Armstrong, and others, I can confidently say the vocal reproduction is as natural as it gets.

Female vocals are velvety and sparkling. Similarly, the Kefine Klean adapts to the character of female voices, delivering them in the most natural and tonally accurate way. I enjoy the slightly warm yet full-bodied presentation of both male and female vocals.

Considering the budget price of Kefine Klean at $50, I believe the midrange performance far exceeds its cost. This set can easily compete with popular IEMs in the $100–150 price range.

Upper mids: Thanks to the silver nozzle and precise tuning, the upper mids are moderately bright and sparkling. They are non-fatiguing during extended listening sessions and do not overshadow other frequency ranges. There’s a sense of airiness, particularly noticeable in vocals and, to some extent, instruments. I’d say the upper mids beautifully complement the vocal and instrumental delivery, enhancing detail and keeping the sound alive.

TREBLE

Moderately bright, sparkling, and airy. I really enjoy the lightness of the high frequencies. This range is exceptionally pleasant to listen to, and I’m genuinely impressed by how Kefine achieved this. The treble are pure and light, entirely free from sibilance or graininess—an absolute delight. Cymbals have a crisp and resonant tone, while the instrumental treble is sparkling and smooth, with a natural decay. Both male and female vocals reproduce the highs without any harshness or sibilance, making them very enjoyable.

Separating, sound stage

COMPARISON:

Kefine Klean vs Simgot EA500LM:

I would like to compare the Kefine Klean with similar IEMs in terms of sound profile—Simgot EA500LM.

Both models are made of metal, with a similar shape and fit. Their packaging is also quite similar. However, the Simgot EA500LM is $40 more expensive.

In terms of sound, the two models are quite close, with some differences. The bass on the Kefine Klean is superior in quality compared to the Simgot. Their midrange is roughly on par, but the Simgot is more technical, while the Kefine is more melodic. The Simgot features their signature bright treble, whereas the Kefine Klean delivers a softer and less pronounced high end. The key difference lies in their overall presentation: the Simgot EA500LM provides an analytical sound, enabling you to piece together the details into a cohesive picture, while the Kefine Klean offers a smoother and more refined sound. In 2024–2025, I don’t see the need to pay extra for the Simgot EA500LM when the Kefine Klean is available.

Kefine Klean vs BQEYZ Cloud:

The next comparison I’d like to make is with the vocal king—BQEYZ Cloud.

Both models are made of metal and share a similar shape and fit. Regarding accessories, BQEYZ offers a wider selection of eartips, whereas the Kefine Klean provides interchangeable nozzles. However, the BQEYZ Cloud is three times more expensive than the Kefine.

The sound of the BQEYZ is tuned to deliver the most natural and authentic midrange, where the Kefine Klean can’t quite compete. However, Kefine surpasses BQEYZ in both bass quality and quantity. The mids on the BQEYZ are, in my opinion, flawless, and no other IEM has managed to outperform them yet. On the other hand, the highs on the Kefine seem more accurate and realistic. I would describe the BQEYZ’s sound as vocal-focused, while the Kefine comes across as more balanced and tonally “correct” overall.

I noticed that IEMs with balanced armature drivers tend to have a narrow and confined soundstage, and the Rose Technics Star City 5 Pro is no exception. I would describe them as more monitor-like rather than analytical. With these, you won’t be piecing sounds together like a LEGO puzzle.

In terms of separation, the sounds don’t stack on top of each other but are delivered very smoothly and balanced, one after the other. I have no complaints about the imaging—you can easily pinpoint the direction of instruments or vocals.

CONCLUSION:

Kefine Klean are IEMs that are nearly perfect in every aspect, from the unboxing experience to the finest details of their sound. Honestly, it was difficult for me to find any flaws in this model. I believe Kefine has done an excellent job of creating an affordable alternative to the more expensive Kefine Delci, without compromising on either build quality or sound performance. Their sound truly exceeds their price, and I’m ready to compare them to IEMs in the $50–150 price range.

It’s been a long time since I’ve heard such naturalness and tonal accuracy. Combined with Kefine’s signature tuning, the Klean shine even more. I love how they adapt to the presentation and adjust their tonality, as if they have AI built inside.

I believe these are a must-have dynamic IEM under $50 that deserves a place in your collection.