Short answer: the Kefine Klean. It ranks #248 of 1291 in-ear headphones by sound quality, rated 4.2/5, at $53.61; the KZ ZS10 Pro X ranks #345, rated 4.1/5, at $53.19. Close enough in price that the sound-quality gap is the deciding factor.
Why pick the Kefine Klean: A single 10mm dynamic driver holds an average deviation of about 1.5 dB from target in squig.link hobbyist measurements, for a preference score of 77. Watch for: The treble is uneven, with a 3.7 dB peak near 8 kHz followed by a 4.4 dB dip near 9.7 kHz, which can add a little edge to sibilance while blurring cymbal decay.
Why pick the KZ ZS10 Pro X: The median of 10 hobbyist measurements gives it a very good Harman preference score of 75 with a 1.86 dB spread, and its mids sit within about 0.9 dB of target, so vocals and instruments sound natural. Watch for: A 6.4 dB peak near 10.6 kHz can make cymbals and sibilance sound sharp.
Buy the Kefine Klean. It is rated higher for sound quality, and the $0.42 you would save on the KZ ZS10 Pro X does not close the gap.
Looking for alternatives? See the complete Headphones rankings.
A single 10mm dynamic driver holds an average deviation of about 1.5 dB from target in squig.link hobbyist measurements, for a preference score of 77.
Amazon $53.61 eBay
The median of 10 hobbyist measurements gives it a very good Harman preference score of 75 with a 1.86 dB spread, and its mids sit within about 0.9 dB of target, so vocals and instruments sound natural.
Amazon $53.19 eBayPrices on this page were last checked October 16, 2026 at 5:46 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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Specifications Side By Side
| Kefine Klean | KZ ZS10 Pro X | |
|---|---|---|
| Price | $53.61 | $53.19 |
| Ranked | #248 of 1291 in In-Ear Headphones | #345 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 77 (median of 30 squig.link measurements, calibrated to AutoEQ) | 75 (median of 10 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.52 dB standard deviation | 1.86 dB standard deviation |
| Tonal Tilt | -0.57 (negative is warmer, positive brighter) | -0.33 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.9 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+0.7 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Hybrid |
| Drivers | 1 x 10mm dynamic | 1 x 10mm dynamic + 4 x balanced armature |
| Impedance | 32 ohms | 29 ohms |
| Sensitivity | 107 dB | - |
| Weight | 0 lbs (10 g) | - |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | 20Hz - 40kHz |
Frequency Response Compared
Both headphones’ measurements overlaid on the Harman target. Above the target sounds louder in that range, below it quieter. Each curve is the median of several independent measurements, shifted so its 500 Hz to 2 kHz average sits at 0 dB, so only the tuning is compared.
Measurement data: the Kefine Klean from aftersound, ankramutt, atechreviews, audioamigo, awsmdanny, bassaudio, boizoff, cqtek, csi-zone, dl, ducbloke, eplv, fahryst, hbb, iemworld, jaytiss, lumerion, musicafe, obodio, practiphile, pw, regancipher, silicagel, sl0the, soundcheck39, soundignity, theaudiostore, timmyv, tonedeafmonk and treblewellxtended; the KZ ZS10 Pro X from ankramutt, flare, hoods, ianfann, iemworld, pw, superreview, theaudiostore, treblewellxtended and vortexreviews, all via squig.link.
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