By aspect — in detail
The one thing nearly everyone agrees is large. Both rigs put it about 13 dB above the midrange at 20 Hz, and unlike most sub-bass-only shelves it is still up around 7 dB at 100 Hz, so there is real mid-bass behind it. Praise is for depth, speed and texture; the dissent is a minority who hear it as bloated, and one reviewer who hears it as merely natural.
“The low-end of the Letshuoer Astralis is very big and hard edged with a meaty and bullish presence and it is clearly the focus of this iem”
Chris Love, Mobileaudiophile
“Sub-bass boosted all-rounder, very dynamic, engaging, and vibrant with great musical contrast.”
Jays Audio, via IEMRanking
“it feels bloated and constantly bleeds into the lower mids”
blay, Head-Fi (2.5★)
Measured
Both rigs agree closely: +12.96/+12.98 dB at 20 Hz (squig.link) and +13.16/+12.80 dB (Audio Amigo), relative to 500 Hz — still +7.0 to +7.6 dB at 100 Hz and +3.2 to +3.5 dB at 200 Hz. That is a genuine mid-bass lift, not a sub-bass-only shelf.
⚠ vs. listeners — Two claims sit outside the data. Audiophile-Heaven's "far from sounding basshead" is hard to square with a ~13 dB shelf on two rigs; and thaslaya's light mid-bass is true only relative to the sub-bass, since 100 Hz still measures about 7 dB up.
Sources split. One camp hears a warm, full-bodied midrange that flatters male voices; the other hears it thin, hollow or pushed behind the bass. The graphs explain both at once: ear gain peaks unusually low (1.7–1.9 kHz) and modestly, then falls away by 3 kHz, which lifts lower-male-vocal weight while leaving female vocals set back.
Measured
Ear gain peaks at only +7.19 to +7.48 dB around 1.75 kHz (squig.link) and +8.19 to +8.51 dB around 1.85–1.93 kHz (Audio Amigo), then slides 3.8–4.5 dB by 3 kHz — while the bass shelf sits some 4.5–5.5 dB above that peak.
⚠ vs. listeners — Both camps are describing the same curve from different ends. thaslaya independently spotted the mechanism by ear, noting the set's earlier upper-mid accentuation puts male singers forward — which is exactly what a 1.75 kHz peak with a 3 kHz dip does.
Where it splits
warm and full-bodied — especially male vocals57%
“Melodic mids, great note weight, excellent earthy timbre, never shouty, great for vocals”
Chris Love, Mobileaudiophile
thin, hollow or recessed behind the bass43%
“Vocals generally lean toward the thin and sterile side of the spectrum.”
thaslaya
The most contested aspect, and the reason opinion on this set is so wide. Most sources hear it smooth, safe and non-fatiguing — some to the point of calling it dark. A minority hears it thin, zingy and at times harsh. The same unit measured at three insertion depths produces three different treble curves, which is the likeliest cause.
Measured
Insertion depth barely touches bass or mids — 20 Hz moves 1.03 dB and the ear-gain peak 0.29 dB across shallow, default and deep — but it rewrites the top. The main treble peak migrates from 6.3 kHz (shallow, +8.3 dB) to 8.1 kHz (default, +6.8 dB) to 9.25 kHz (deep, +9.1 dB); 8 kHz alone swings 9.1 dB, from −2.27 dB shallow to +6.79 dB default.
⚠ vs. listeners — Super* Review scored the treble E while noting the Astralis measured as the more restrained set of its comparison group — a contradiction the depth series resolves, since a shallower seat parks an 8 dB peak at 6.3 kHz right in the sibilance region. Listen Vibes describes the deep-insert curve almost exactly, hearing a dark lower treble alongside genuine upper-treble air.
Where it splits
thin, sharp or outright harsh25%
“Treble is thin, incisive, and sometimes harsh; could use more air and extension”
thaslaya
Broadly read as warm and bass-forward, usually called U-shaped; the measurements back that unambiguously. Two dissents exist and point opposite ways — one reviewer hears it as cold and sterile, another as flat-out neutral — but neither matches the response curve, which is bass-dominant on both rigs.
“The overall timbre is warm and smooth, slightly dark and pleasantly laid-back.”
Chris, The Headphoneer
“Warm, bassy planar with strong texture, smooth treble, and competitive technical performance.”
Audio Amigo, via IEMRanking
“Astralis is a natural-neutral tuned IEM with a nice sharp treble, natural bass and natural midrange”
Audiophile-Heaven
Measured
A ~13 dB bass shelf over an ear-gain peak of only +7 to +8.5 dB is a bass-forward tilt on both rigs, with no tuning switches or nozzles to change it.
⚠ vs. listeners — The "cold and sterile" reading describes note weight and timbre rather than frequency tilt; the "neutral" reading is not supported by either measurement.
Soundstage
Contested · 7 srcGenuinely split, and not along the usual lines: two sources call the stage wide and close to holographic, while roughly as many call it merely average for the money. Those who like it tend to describe width rather than depth.
Where it splits
wide, spacious, immersive44%
“Nothing ever sounds closed in or narrow and the Astralis never sounds like a 2D plane of sound in front of me.”
Chris Love, Mobileaudiophile
average for the price — nothing remarkable56%
“Soundstage is only average in size”
Ryujinie, Head-Fi
Mostly praised for placement accuracy and separation, with separation singled out as a strength even by the set's critics. One Head-Fi reviewer is a firm dissenter, and the aggregator rates it merely average for the class.
“The separation is one area of the technicalities in which Astralis excels.”
thaslaya
“Soundstage and imaging are only average for the class”
Audio Amigo, via IEMRanking
“Imaging performance is below average”
Ryujinie, Head-Fi
Rated good-to-very-good by most, with the caveat that detail arrives smoothly rather than being pushed forward — several sources note it is not tuned to be a detail specialist. The lone strong dissent comes from the reviewer who also hears the bass as masking everything.
“this might be one of the most detailed planars for its tonality”
koyawmohabal, Head-Fi
“Superb resolution and detail, literally competing with IEMS twice the price”
Audiophile-Heaven
“While the S12 Pro is surgical and clean, the Astralis is muddy.”
blay, Head-Fi (2.5★)
A consistent strength. Reviewers describe low compression and strong bass dynamics, and the aggregator's dynamics grade is its highest. The reservation is that the polite upper midrange can make the whole presentation feel less energetic than brighter planars.
“Highly dynamic with little compression”
Audiophile-Heaven
“Macro dynamics and overall energy can feel lacking compared to brighter planar sets”
Ryujinie, Head-Fi
Widely praised — light aluminium shells, vented so pressure does not build, and one of the better-fitting sets Letshuoer has made. Reviewers disagree on whether the shell is compact or slightly large, which tracks ear size; several note tips matter more here than usual, because the seal changes what you hear.
“Tip rolling necessary for best fit and seal”
Kingnubian, Head-Fi
“The shells are slightly large. People with smaller ears may find that the outer edges make contact with their ears.”
Kagrra, Head-Fi
“there is no void and no driver flex, which is better than even some flagship planar driver IEMS”
Audiophile-Heaven
Isolation
Moderate · 3 srcLightly covered, but what there is runs positive — a sealed aluminium shell with only small pressure-relief vents blocks a useful amount of noise and leaks little.
“around 20 dB to 25 dB of pure passive noise isolation”
Audiophile-Heaven
Build
Strong consensus · 8 srcThe least controversial part of the set. The CNC aluminium shells and the modular 3.5/4.4 mm cable draw praise from every source, including the harshest critics, and the bundled USB-C dongle is treated as unusual generosity at the price. The recurring gripe is the plastic screw-top case.
“Exceptional build quality in general”
Audiophile-Heaven
“Solid and comfortable shell design with a great aesthetic”
thaslaya
“cable could be better for the price”
koyawmohabal, Head-Fi
The sharpest disagreement after treble. Supporters call it one of the best warm planars under $200; detractors point out that Letshuoer's own cheaper S08 and S12 Ultra do the same job, and that at this price the field is crowded. The aggregator's five expert scores span 3.0 to 7.4 out of 10.
Where it splits
worth the money — a standout warm planar under $20062%
“the Astralis is without question one of the best warm, bassy, musical planars under $200”
Chris Love, Mobileaudiophile
not at this price — cheaper siblings do it better38%
“the Astralis might be the least appealing of the mid-fi planars that I own”
thaslaya
