Short answer: a tie on sound quality. Both are rated 3.7/5 (#632 and #640 of 1291 in-ear headphones) at nearly the same price ($22.99 vs $24.99), so choose on features and fit.
Why pick the KZ ZST: In oratory1990’s measurement the preference score is 70, with bass about 2.3 dB above target from 60 to 200 Hz for extra warmth and punch, and sub-bass tracking the target within 0.1 dB. Watch for: A 9.4 dB dip near 4.4 kHz and 3.7 dB lower presence from 3 to 6 kHz pull back vocal clarity and the attack of snares and guitars.
Why pick the Moondrop Chu 3: The median of 16 hobbyist measurements gives it a solid Harman preference score of 70 with a 2.14 dB spread, and its mids sit within about 0.6 dB of target, so vocals and instruments sound natural. Watch for: Presence sits about 3.1 dB low with a 5.3 dB dip near 5.4 kHz, so vocals and instruments lose some bite.
Buy the KZ ZST or the Moondrop Chu 3 on features: they are rated the same for sound quality at close to the same price.
Looking for alternatives? See the complete Headphones rankings.
In oratory1990’s measurement the preference score is 70, with bass about 2.3 dB above target from 60 to 200 Hz for extra warmth and punch, and sub-bass tracking the target within 0.1 dB.
Amazon $22.99 eBay
The median of 16 hobbyist measurements gives it a solid Harman preference score of 70 with a 2.14 dB spread, and its mids sit within about 0.6 dB of target, so vocals and instruments sound natural.
Amazon $24.99 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
| KZ ZST | Moondrop Chu 3 | |
|---|---|---|
| Price | $22.99 | $24.99 |
| Ranked | #632 of 1291 in In-Ear Headphones | #640 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Harman Preference Score | 70 (measured by oratory1990, via AutoEQ) | 70 (median of 16 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.31 dB standard deviation | 2.14 dB standard deviation |
| Tonal Tilt | -0.47 (negative is warmer, positive brighter) | -0.59 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.1 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.8 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Hybrid (1 dynamic + 1 balanced armature) | Dynamic |
| Drivers | 1 x 10mm dynamic + 1 x balanced armature | 1 x 10mm dynamic |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | 12Hz - 50kHz (Manufacturer specified) |
| Back | Closed | Closed |
| Impedance | - | 16 ohms |
| Sensitivity | - | 118 dB/Vrms |
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 KZ ZST from audioamigo, bassyalexander, hbb, iemocean, isaiahse, melatonin and sl0the; the Moondrop Chu 3 from aden, aquaphobic, atechreviews, audioamigo, bassaudio, bedrock, boizoff, breampike, dvewlsh, eplv, fernandagunsan, hbb, iemocean, practiphile, precog and superreview, all via squig.link.
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