Disclosure: I’d like to thank Kefine for providing me with the Klean for this review. All thoughts and opinions are my own, and Kefine had no say or input on the contents of this review.

At $49 for a single dynamic driver IEM, the Kefine Klean enters one of the most competitive segments in the IEM market, where every new release faces serious scrutiny from budget-conscious audiophiles waiting for the new best price for performance IEM.

What caught my attention with the Kefine Klean, though, is its approach to tuning. Rather than chasing experimental sound signatures, it follows the consumer-favorite 2019 Harman target, delivering a balanced, mildly V-shaped tonality with technical performance focused on holographic imaging. The hefty polished cast alloy metal construction and 10mm dynamic driver certainly don’t hurt either, creating a package that appears to punch above its modest $49 price tag.

Technical specs and marketing claims only tell you so much, though. This review examines the design, comfort, sound quality, and gaming performance to see if the Kefine Klean earns a spot in your collection or gets lost in an already crowded market. Let’s get into it.

• Kefine Klean
• 1.2m silver-plated copper wire cable with 3.5mm SE termination
• 1.2m silver-plated copper wire cable with USB-C termination (included with my version)
• Hard zipper storage case
• Set of S, M, L silicone eartips
• 2 sets of nozzles
• Manual

The overall presentation feels more premium than expected, with everything neatly organized and well-protected. The inclusion of interchangeable tuning nozzles stands out as particularly impressive, as this level of sound customization rarely appears at this price point.

The cable deserves mention here, too. It’s a 2-core oxygen-free copper design that feels substantial without being stiff. At roughly 1.2 meters long, it provides good reach while the 0.78mm 2-pin connectors create a secure fit. Microphonics stay minimal, and the strain relief looks adequate for regular use. While it won’t rival aftermarket cables costing as much as these entire IEMs, it’s significantly better than the typical budget IEM cable, and I really do like the feel and look of it.

The semi-rigid case provides decent protection for daily carry while remaining very compact and travel-friendly. The fabric material gives it a distinct look and feel, too. Not the most spacious of cases, but it gets the job done and is a solid value add here.

Picking up the Kefine Klean immediately tells you this isn’t your typical budget IEM. The full metal construction feels substantial and solid. The Klean uses metal injection molding to create its distinctive six-sided design, with a rectangular pattern etched on the faceplate and the KEFINE logo displayed prominently in white. The black finish looks sleek and holds up well to daily use, with gold-plated nozzles providing a nice contrast that adds a bit of elegance to it.

Each shell weighs about 9.8 grams, noticeably heavier than plastic alternatives due to the metal construction. The extra weight doesn’t become bothersome during regular use, though. The compact dimensions mean they don’t stick out much from your ears, making them practical for everyday wear and even sleeping while wearing them.

Two small vents, one near the nozzle and another on the inner face, contribute to the acoustic design. I appreciate that the Torx screw secures the back panel rather than sitting on the faceplate, keeping things clean-looking while also adding an industrial look to the IEM when you notice it.

Despite being all metal, these surprised me with how comfortable they are. The shells follow your ear’s natural shape well, though the nozzle diameter might feel slightly wide if you have smaller ear canals like I do, but the Klean didn’t cause any discomfort for me. The ergonomic shape provides good stability, but getting the right ear tips is crucial for a proper seal. Once you find the right fit, they’re comfortable enough for long listening sessions.

USB-C Cable

Kefine also offers a USB-C cable for the Klean that features in-line controls with a built-in microphone. The USB-C connection has an integrated DAC, so it’s just plug and play into any USB-C device. The DAC supports up to 32-bit/384kHz playback, at least from what I can see when I plug into a Windows computer.

There is no sound quality difference between this cable and the 3.5mm version, at least to my ears, so don’t expect any DSP magic. The cable also feels and looks exactly the same as the 3.5mm version, which, as you have already read, is a good thing.

The in-line controls work well and as expected. The Play/pause button is positioned beneath the volume buttons, which took some getting used to, but it is shaped differently from the volume buttons and has a small nub on it to help you identify it with just your fingers. Overall, I really like this cable as an option, and on top of using it with my smartphone, I even used it with some DAPs as it was very convenient.

The Klean’s 32-ohm impedance and 107dB sensitivity make it easy to drive from just about anything, performing admirably even from a smartphone or simple dongle DAC. It does scale up nicely with better amplification, though, particularly expanding the soundstage width. I found the Klean pairs really well with neutral ESS Saber-based sources for a more technical presentation, while slightly warmer sources (like CX31993 chip devices) enhance its musicality without sacrificing detail.

The Kefine Klean follows a sound signature that balances warmth and detail with a mild V-shaped tuning that leans toward the Harman target curve. As I alluded to earlier, the Klean does include two different nozzles that affect the sound profile slightly. The nozzles are differentiated by the color of the mesh inside the nozzle itself.

Tuning Nozzles: Silver vs Black

The silver nozzles (pre-installed) offer a smoother, slightly warmer sound with more prominent bass. The black nozzles boost energy in the upper midrange and lower treble, creating a more V-shaped profile with greater perceived detail and wider soundstage. If you’re sensitive to treble, stick with the silver filters. Detail enthusiasts will probably prefer the black option. I personally found the silver nozzles to align more with my musical tastes, which you can see in the playlist links above. My subjective impressions below were all done when listening with the silver nozzle.

Bass

The bass extends impressively into the lower frequencies with a satisfying sub-bass rumble that never overwhelms the mix. Clean and controlled, it adds proper weight to tracks like “Angel” by Massive Attack, where you need that low-end foundation without muddying the atmospheric elements. The mid-bass delivers a tight, punchy performance with excellent speed and articulation. Though slightly woolly at times, it maintains enough definition to keep bass lines distinct even in complex metal tracks like “Ticks & Leeches” by TOOL.

Midrange

Male vocals sound rich and full-bodied with natural warmth. Female vocals shine with clean presentation and no harshness. Instruments maintain proper spacing and definition, allowing even complicated arrangements to sound coherent rather than congested.

Treble

The treble extends admirably, creating an open, airy sound that gives music room to breathe. Cymbals and string instruments present naturally with good micro-detail retrieval without becoming harsh or fatiguing. This balance makes the Klean suitable for extended listening sessions while maintaining enough sparkle to prevent it from sounding dull or boring.

Soundstage and Imaging

Soundstage width exceeds expectations for this price range, though depth is more limited. Imaging proves surprisingly accurate with good lateral panning and stable positioning of instruments. This creates a believable spatial presentation where center vocals have excellent definition and presence.

Gaming

For gaming, the Klean performs admirably for the type of games I play. Environmental cues are presented with good directionality, making it effective for casual gaming where immersion matters. The bass adds weight to explosions without masking critical dialog or positional audio cues. Competitive multiplayer games also perform well as the tuning presents a good balance of being able to hear footsteps and gunshots with accurate directionality.

The Kefine Klean may be my new favorite all-rounder IEM, as it performs extremely well in most music genres, balancing detail and musicality. At $49, this IEM delivers performance that frankly surprised me. What impressed me most was the technical performance. Soundstage width and imaging capabilities genuinely exceed what you’d expect at this price point, though depth does remain somewhat limited. The interchangeable tuning nozzles also add real value to the package.

The Harman-inspired tuning hits that sweet spot for most listeners, and for me. Bass stays controlled yet impactful, the midrange presents vocals with natural warmth and clarity, and the treble extends well without fatigue during longer sessions.

Gaming performance deserves mention too, as the Klean delivers solid positional audio capabilities, making it genuinely versatile for both music and gaming.

The metal construction does add some weight that might bother those seeking ultra-lightweight options. It’s not a deal-breaker for most ear shapes, but worth considering if you’re sensitive to heavier IEMs.

The Kefine Klean earns my recommendation as a legitimate standout in the budget IEM market. It proves that excellent sound quality, premium construction, and thoughtful features don’t require spending hundreds of dollars.

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