By aspect — in detail
Tonality
Strong consensus · 8 srcThe one thing nobody argues about: a neutral tuning with a gentle sub-bass shelf and a touch of lower-midrange warmth, close enough to flat that reviewers use it as a reference point for other sets.
“one of the more neutral sounding sets on the market”
VSG, TechPowerUp
“The best way to describe the Softears Studio4s’ sound signature is “neutral.””
Azzief Khaliq, Voltcave
Measured
Three independent IEC-711 rigs agree on the shape: a +4.8 to +6.4 dB shelf at 20 Hz that is back within 1 dB of level by 200 Hz, a flat 200 Hz–1 kHz stretch, and a modest ear-gain peak of +8.3 to +9.6 dB at 2.85–2.95 kHz.
⚠ vs. listeners — Where listeners land inside that neutrality varies: Cuckoo Studio calls the result warm (blaming the 6 kHz dip), while Head-Fi's thaslaya and EnemySpider hear a slightly bright tilt. The graphs support both — the dip is real and so is the 3 kHz and 8 kHz energy above it.
The most praised part of the set, and the closest thing to consensus after tonality: natural, uncoloured vocals and instruments with no obvious recession or shout. The dissent is narrow — that a tuning this even leaves vocals sitting further back than a vocal-first listener wants.
“The midrange is where Studio 4 shines”
Cheryl, Headfonics
“The midrange is the star of the show with the Softears Studio4s”
Azzief Khaliq, Voltcave
“As a lover of vocals, the midrange falls a bit flat for me.”
thaslaya, Head-Fi
Measured
A flat 200 Hz–1 kHz lower midrange with the ear-gain peak placed at 2.85–2.95 kHz and sliding 3.3–3.9 dB down to 4 kHz — forward vocals without the 3 kHz spike that produces shout.
Sources split hard. One camp hears a smooth, well-extended, never-sibilant top end and calls it the set's best feature; another hears a monitor that plays it too safe and leaves out the bite and air. The measurements say both camps are right about different octaves.
Measured
Every one of six traces from three rigs shows a trough at 6.4–6.7 kHz sitting 4.0–5.8 dB below the 5 kHz shoulder and 3.7–5.6 dB below an 8 kHz peak. Cuckoo Studio, measuring against Harman 2018, reads the same feature as roughly 9 dB of attenuation near 6 kHz.
⚠ vs. listeners — The split tracks the curve rather than taste alone: the 6.5 kHz hole is the missing bite, and the 3 kHz and 8 kHz energy is the crispness — different octaves of one response. Head-Fi's thaslaya hears both at once, calling the treble "a bit of a conundrum." Above 10 kHz, where the air argument lives, the rigs disagree by up to 5.7 dB at 15 kHz, so no measurement settles that half of it.
Where it splits
smooth, extended, realistic — the highlight55%
“The S4’s treble sounds open and extends well without being aggressive.”
Berkhan, Headfonia
too safe — missing bite and air45%
“the Studio 4’s treble is too safe; it sounds like it’s missing entire parts of the mid-treble”
Precogvision, headphones.com
Unanimously quality over quantity — fast, tight, and completely clear of the midrange, with sub-bass that reaches down but very little slam behind it. What sources argue about is texture: some hear it as a genuine strength, others as the giveaway that these are balanced armatures.
“The bass on the Softears Studio 4 is tight and controlled”
Cheryl, Headfonics
“the bass is surprisingly tight and precise for an all-BA set”
VSG, TechPowerUp
“It sounds fairly plasticky, missing tasteful decay.”
Precogvision, headphones.com
Measured
A sub-bass-only shelf: +4.75 to +6.40 dB at 20 Hz across six traces, peaking +5.30 to +6.63 dB at 30 Hz, and back to between +0.06 and +0.99 dB by 200 Hz. There is no mid-bass lift at all.
⚠ vs. listeners — Head-Fi's thaslaya hears it as "more mid-bass focused than sub-bass" — the opposite of what all three rigs show. The shelf is entirely below 200 Hz, which is why most listeners describe depth without punch.
Soundstage
Contested · 6 srcThe most one-sided of the contested aspects. Most sources call the stage narrow or cramped — Headfonia makes it the review's headline complaint, "There needs to be better layering and better staging, especially in terms of width" — but a real minority, including the ranking aggregate, hears it as wide. Nothing measurable adjudicates perceived space, and it is worth noting the split runs by source type: the narrow camp is where the bench-equipped written reviews land, the wide camp is drawn largely from video reviewers and ranking sheets.
Where it splits
narrow — the set's main technical weakness68%
“the soundstage is on the more narrow side of average”
VSG, TechPowerUp
genuinely wide, if shallow32%
“Staging on the Studio 4s has a good amount of width and height but is a bit lacking in depth.”
Cheryl, Headfonics
Imaging
Strong consensus · 8 srcPrecise placement and clean instrument separation are agreed on across every class of source, including the one reviewer who dislikes almost everything else about the set.
“It does have fairly precise imaging”
Precogvision, headphones.com
“the Studio 4 has one of the best imaging I have tried in an IEM released in recent times”
monkonomics, Head-Fi
Measured
Cuckoo Studio ties it to channel matching: "the nearly perfect frequency response matching gives STUDIO4 an extremely robust center image." Precogvision's own pair tracks within about 0.2 dB below 5 kHz.
⚠ vs. listeners — Not every unit measures that way. Head-Fi's EnemySpider posted his own graph with the note "Channel matching is not great!", and the vsg and atechreviews pairs differ by up to roughly 1 dB in places — seal and insertion depth move this as much as manufacturing does.
Most sources rate resolution and separation at or above the price; the critical camp calls it surface-level. The gap is wide enough that this is the aspect where the field's scores diverge most after treble.
“Instrumental separation is excellent and I feel the Studio4 even hits above its price class here”
VSG, TechPowerUp
“the Studio 4’s detail mostly comes across as surface level, possibly around a “B” grade in my book”
Precogvision, headphones.com
The clearest agreed-on weakness. Nobody calls the Studio4 punchy; opinions run from "lively enough" to outright dismissal, and the aggregate grades it lower than any other trait.
“the dynamics of the Studio 4 are not worth talking about other than to say they are unsatisfactory”
Precogvision, headphones.com
“It’s not a particular punchy set thus, yet manages to sound lively and detailed.”
VSG, TechPowerUp
Measured
IEMRanking's aggregate of nine expert reviews grades dynamics B− — its lowest grade for the set, against A for tuning, mids, treble and soundstage.
Isolation
Strong consensus · 6 srcExceptional, and agreed on by every source that mentions it. The unvented shells and the deep, semi-custom fit block more than almost any other wired IEM at the price.
“The shape of the shell creates a remarkable seal that drowns out outside noise effectively.”
Cheryl, Headfonics
“The Studio 4s have non-ventilated shells, so they isolate very well.”
Azzief Khaliq, Voltcave
Light, low-profile shells that most reviewers wear for hours without complaint. The two recurring caveats both come from the same design choice: the nozzle has no retaining lip, so tips slip, and the unvented shell can build pressure.
“one of the better fitting and isolating IEMs on the market”
VSG, TechPowerUp
“The nozzle of the IEM is so smooth that wide-bore ear tips slide off. The nozzle does not have a lip.”
EnemySpider, Head-Fi
Measured
Roughly 5.8–5.9 mm at the widest point of the nozzle, ~5.6 g per shell, and no pressure-relief vent anywhere on the body — the physical cause behind both the isolation and the seal complaints.
The monitor itself is well made — smooth resin, recessed 2-pin sockets, a hard waterproof case — and measures consistently unit to unit. What draws fire at $449 is everything around it: a stiff, single-ended-only cable and three pairs of tips in one style.
“The build quality is exceptional, with a premium feel on both the hands and ears.”
Berkhan, Headfonia
“It's not very soft or supple, feels a bit cheap in hand, and has some memory issues. For $450, I'd expect a much nicer cable.”
thaslaya, Head-Fi
Measured
Cuckoo Studio's distortion sweeps at 86, 96 and 104 dB hold under 1% with matched left and right channels: "there are no problems with quality control."
Bimodal, with almost nobody in the middle. One camp says nothing about the Studio4 feels overpriced; the other says it is simply not competitive at the asking price. Some of that gap is arithmetic rather than taste — the positive camp mostly argues against a sale price, TechPowerUp having seen it near $368, while the negative camp argues against the $449 list. Both numbers are live today: ShenzhenAudio sells it for $348, HiFiGo and Linsoul for $449.
Where it splits
fairly priced for what it does57%
“there's nothing here which is making me think the Studio4 is overpriced”
VSG, TechPowerUp
not competitive at the asking price43%
“the Studio 4 is not bad, but it’s also not necessarily competitive for its price point”
Precogvision, headphones.com
