By aspect — in detail
The single most-argued axis. The Chu II carries a sharp peak above 10 kHz, and listeners split on how it lands: most hear a clean, well-extended, non-fatiguing top end (often called cleaner than the graph looks), while a substantial camp — and the aggregate's headline sonic complaint — hears it as spicy, piercing or sibilant. The split tracks treble-sensitivity, tips, source and volume, and several owners report it mellowing over the first weeks of use.
Measured
Measured on a GRAS 45CA (ASR), the response sits very close to the Harman target with low distortion, but with an overshoot/peak around 14 kHz; the Crinacle / squig.link 711 graphs show the same sharp spike above 10 kHz that the critical camp points at.
⚠ vs. listeners — The same high-treble peak is heard as 'clean and non-fatiguing' by most reviewers (and measures close to target with low distortion) and as 'spicy, piercing, sibilant' by a sizeable owner minority — the aggregate's #1 sonic complaint. Tips, source, volume and a few weeks of listening all move it ('the treble has ever so slightly become rounder and less piercing'), so there isn't one 'true' treble here.
Where it splits
Clean, well-extended and non-fatiguing — cleaner than the scary graph suggests.45%
“Highs are well-extended and articulate, offering a touch of sparkle without becoming harsh or sibilant.”
Acexpurplecore, r/headphones
Spicy, piercing and sibilant — the main weak point, especially for treble-sensitive ears.55%
“These have spicy treble and instruments can be piercing at times.”
AudioNotions
Two genuinely split readings. The all-metal shell is a near-universal high point — premium and overbuilt for ~$20, and the new detachable cable fixes the original Chu's worst flaw. But the brass nozzle oxidises (turns green), the set is a little moisture-sensitive, the finish can tarnish, and the stock cable is widely called flimsy — so owners divide on whether longevity is a non-issue or a real caveat.
Measured
Zinc-alloy shell with a machined brass nozzle, ~8 g per bud, detachable 0.78 mm 2-pin, 3.5 mm single-ended. The brass nozzle greens with humidity/sweat (normal for brass, but cosmetic and occasionally flaky); the aggregate lists 'Durability and moisture issues' as its top owner con.
Where it splits
Overbuilt metal shell that lasts — the green brass nozzle is normal, not a fault.45%
“Chu II owner here > 3 years, no oxidation despite of humidity level in Malaysia, and no paint chipping issue either.”
Either-Prior6259, r/iems
Real longevity caveats — nozzle tarnish/oxidation, moisture sensitivity and a flimsy cable.55%
“the finish on these nozzles has tarnished noticeably.”
Bedrock Reviews
Broadly a highlight — an elevated, sub-bass-focused low end that several call the best in its price class and a clear step up from the original Chu in fullness and texture. The caveats are consistent: it can sound a touch slow, and its quantity leans on the seal — the sub-bass 'lacks' on the shallow stock tips and comes alive with a better tip/source. A few simply find it too much.
“The sub-bass I found to stand out and be the best sub-bass I have heard from a budget IEM to date.”
AudioNotions
“As for the bass, they are more present but a bit slow, the sub bass lacks using stock tips.”
Mobileaudiophile
Measured
Single 10 mm dynamic driver with bass elevated from the sub-bass up to ~400 Hz; the bump is moderate enough that reviewers note it avoids bleeding into the mids. Quantity is seal- and tip-dependent (wide-bore tips and a better source firm it up).
Competent but the quietest part of the V — slightly recessed, with clearly better timbre and separation than the original Chu. Female vocals sit forward and clear; male vocals and some string instruments can come across thin, hollow or, on busier tracks, a touch shouty. Recessed vocals are a recurring owner note.
“Midrange clarity and instrument separation are excellent.”
Bedrock Reviews
“The mids are slightly recessed, string instruments like guitars sound a bit thin in some tracks.”
Mobileaudiophile
Strong agreement on the recipe: a fun, warm-bright V-shape with a sub-bass lift and energetic highs — noticeably more V-shaped than the original Chu. The interesting wrinkle is that, despite the 'fun' label, it measures close to a neutral preference target; the V is mostly the sub-bass boost plus the high-treble peak sitting on top of an otherwise on-target midrange.
“The Moondrop CHU II is a fun V-shape with a slightly warm bright signature.”
Mobileaudiophile
“the Chu II has a noticeably more V-shaped sound signature compared to the Chu.”
Bedrock Reviews
Measured
Per ASR's GRAS 45CA measurement the response hugs the Harman target closely ('the gaps between its response and our target is very small'); the perceived V comes from the sub-bass shelf and the >10 kHz treble peak rather than recessed mids.
A consistent strength for the money — resolving and clean enough that reviewers repeatedly say it punches above its price, and it holds its own against far costlier sets. The honest ceiling: it's still a $20 single-DD, and a little of the perceived 'air' up top is the treble peak.
“Detail punches above the price level”
AudioNotions
“The Chu II has superior overall detail retrieval and improved soundstage height compared to the Chu.”
Bedrock Reviews
A consistent shape, not a disputed one: intimate and on the narrow side, with average width and decent height/depth — fine for the price but not a strength, and notably close-in for competitive gaming.
“The sound is intimate, the soundstage is quite narrow and lacks some air.”
Mobileaudiophile
“Soundstage does feel a little closed in but does have a good sense of depth to it.”
AudioNotions
Rated good-to-average for the price — accurate-enough instrument placement and separation, helped by the clean mids. It isn't pinpoint, and the intimate stage limits precise localisation (a sticking point for FPS gaming).
“Imaging is fairly accurate and does a good job at giving you a sense of instrument placements.”
AudioNotions
“Imaging is good but limited. Overall I would still say average.”
Mobileaudiophile
Mostly a plus — a small, light all-metal shell that's comfortable for long sessions and works for small ears, and clearly more comfortable than the original Chu thanks to the normal detachable cable. The recurring caveat is the stock tips: the wide, shallow nozzle makes the seal fiddly for some, and a few feel pressure points after a couple of hours.
“Fitment in my ears is better than some other IEMs due to lighter weight and smaller size.”
Audio Science Review
“After a couple of hours of wear, my ears experience discomfort where the anti-helix meets the concha.”
SoundGuys
Lightly covered but generally positive — punchy and engaging for the price, in line with the fun V-shape. The common caveat is that the bass can sound a little slow, softening slam on fast tracks.
“The dynamics are quite good”
AudioNotions
Average to slightly-below-average, as expected from a small vented single-DD — fine for casual use, not a strong isolator, and improvable with better tips. Little disagreement here.
“These are isolation-only buds with average performance.”
SoundGuys
“secureness of fit and isolation are slightly below average.”
Bedrock Reviews
Value
Strong consensus11 srcThe strongest point of agreement — a premium metal build, a detachable cable and a genuinely enjoyable tuning for ~$18.99 is treated as a bargain almost across the board, and a perennial 'best under $20' pick. The one recurring asterisk: if the spicy treble or fiddly stock tips push you to buy better tips and a cable, the all-in cost starts to approach the next tier up.
“Moondrop has once again raised the bar for what is possible in terms of technical performance in a $20 IEM”
Bedrock Reviews
“with all money spent on extra cable and tips, I could've bought an Aria 2 or a Lan II IEM.”
Master_Cartoonist_16, r/iems
Measured
~$18.99 (some listings ~$22.99). Owner aggregates: 4.2/5 from 3,927 Amazon ratings; 63% positive and #26 in IEMs across 484 aggregated Reddit reviews. ASR concludes it is easy to drive (low impedance, comfortable on any source) and recommends it.
