By aspect — in detail
Tonality
Contested · 10 srcEveryone describes the same tuning — flat through the bass and lower mids, with a deliberate lift through the presence region — and splits on whether that is the point of the product or its limitation. One camp hears a genuine reference that shows other in-ears up; the other hears something analytical and cold that works as a studio tool more than a music tuning. The split tracks the calendar more than the ears: the launch-era sources sit in the first camp, the 2018-and-later ones in the second.
Measured
Crinacle grades it A- for tone and A- for technicalities and files its signature as 'Neutral'. His IEC60318-4 measurements put the ER4XR within about 1 dB of its own 1 kHz level from 20 Hz to 300 Hz, with a +9.6 dB pinna-gain peak at 2.7 kHz — flat lows, lifted presence.
⚠ vs. listeners — Both camps are reading one graph correctly. Against Etymotic's own ER4SR the XR lift is real; against a Harman-style target, or almost any modern in-ear, a ruler-flat low end is bass-light. The verdict moved because the reference point moved, not because the earphone did.
Where it splits
A real reference — flat is the feature, and it shows other in-ears up.68%
“To my ears, the Etymotic ER4 XR is close to perfectly tuned.”
Klaus, Headfonics
Analytical and bass-light — a studio tool more than a music tuning.32%
“This is an expensive IEM at $300 with an out of box performance that doesn't satisfy in this day and age.”
amirm, Audio Science Review
The clearest fault line, and a dateable one. Sources agree on the physics — the low end is linear to 20 Hz with no roll-off and no bloat — and split hard on whether there is enough of it. The 2016-2017 reviews treat the XR lift as exactly right; the 2018-2025 ones treat the same response as polite, modest or outright bass-light, and several reach for EQ. Everyone agrees on one caveat: it does not take a big bass boost gracefully.
Measured
Averaging Crinacle's raw left/right IEC60318-4 exports and normalising at 1 kHz, the ER4XR measures -0.2 dB at 20 Hz — effectively no bass shelf at all. Against the ER4SR it gains +3.6 dB at 20 Hz, +2.0 dB at 100 Hz and +1.3 dB at 200 Hz, converging above 300 Hz, which matches Etymotic's stated '+1-2dB to the mid-bass … and 3-4dB to the lower-bass and sub-bass' and The Absolute Sound's independent reading of the same lift.
⚠ vs. listeners — Nobody is mis-hearing. Both camps describe a response that is flat to 20 Hz; they disagree only about what flat is worth. Two sources also note the lift is near the driver's limit — Audio Science Review measured limiting at 114 dBSPL, and Headfonics found 'the bass performance will quickly distort when boosted further' — so the EQ that fixes the quantity has a ceiling.
Where it splits
The lift is judged and clean — taut, extended, never muddy.53%
“Initially I was concerned that the XR would have a muddier and less refined mid and low bass, but the upper bass or lower midrange wasn’t obscured by the additional bottom-end energy.”
Steven Stone, The Absolute Sound
Still bass-light — linear but modest, and wanting a shelf.47%
“I first dialed in the bass shelving filter. That added warmth to even female vocals where you don't think you need much bass.”
amirm, Audio Science Review
Consistently described as upfront and energetic, with the emphasis in the upper mids rather than the lower — a deliberate design choice, since deep insertion bypasses the part of the outer ear that would normally supply that boost. Sources broadly agree it is the source of the ER4XR's clarity; they differ on how often it tips into shout. Reviewers using dense or bright material hit it most, and tip choice measurably shifts it.
“The Etymotic ER4XRs' top qualities are the detail and definition of the midrange, rewarding the closest listening.”
What Hi-Fi?
“This is probably the most polarizing aspect of this headphone. The upper mids can be a bit forward.”
zjHy, r/headphones
“I find the upper midrange to be slightly boosted.”
Klaus, Headfonics
Measured
The Absolute Sound reports the ER4 line carries 'an intentional boost at 2.7kHz and 5kHz, which simulates and recreates the boost that your ear (due to its shape) normally supplies to all aural stimuli' — the compensation for a fit that bypasses the pinna. Crinacle's data bears it out: +9.6 dB at 2.7 kHz and +4.3 dB at 5 kHz relative to 1 kHz.
The quietest part of the record. Sources line up on a top end that is smooth, extended and essentially free of sibilance or glare — several single it out as the best-executed part of the tuning, and long-session fatigue is rarely reported. The dissent is narrow: the one independent bench calls the lower treble slightly exaggerated, and the most recent reviewer finds sibilants edgy on bright recordings.
“Both the ER4 SR and XR perform amazingly in the treble.”
Klaus, Headfonics
“The high frequencies are also well integrated and impressively resolved, just not super-bright.”
What Hi-Fi?
“Secondly, they are very smooth. No annoying resonances, no harshness, nothing fatiguing in the long run.”
florinandrei, r/headphones
Measured
Audio Science Review's bench found 'some extra lower treble response' against its target and flagged the 'slight treble exaggeration' as an unwelcome surprise; its EQ flattens that region and, in Amir's listening, 'took away some sharpness that was there without it'.
The most reliable praise the ER4XR gets, and the reason the single-driver design keeps being cited as proof that driver count means little: it resolves and separates far beyond what its size and price suggest, and several long-term owners describe it as recalibrating what they expect from other in-ears. The one substantive dissent is recent and specific — that the clarity is inconsistent, and hardens on complex material.
“and you have not noticed how freakishly detailed they are? Especially for the size / price. They're incredible. You just hear so much stuff.”
florinandrei, r/headphones
“the ER4 XR can reveal more micro details than most of the competition”
Klaus, Headfonics
“Detail can be a bit inconsistent on the ER4XR—it’s very clean at times, but occasionally exhibits distortion that comes across as slightly strident.”
Chris, The Headphoneer
Measured
Crinacle grades its technicalities A-. Etymotic channel-matches every pair 'within an industry-leading 1dB across frequencies from 100 Hz to 10 kHz' and ships the certificate in the box.
Soundstage
Contested · 7 srcA genuine split, and an unusually clean one: roughly half the sources call the stage closed, intimate and squarely between the ears, the other half are surprised by how wide and unboxed it sounds for an in-ear. The disagreement is probably structural rather than a matter of taste — deep insertion bypasses the outer ear that normally supplies spatial cues, and how deep you sit the barrel varies with tips and anatomy. Both camps agree on the depth axis: there is very little of it.
Imaging
Strong consensus · 6 srcThe strongest agreement in the whole record after isolation, and it holds across every class of source: whatever the stage is doing, instruments sit in definite, separable places, with layering good enough that reviewers follow individual lines through crowded mixes. The only caveat comes from the most recent source, which finds the precision slips on dense passages.
“you will be rewarded with category-leading isolation levels and precise imaging with excellent depth recreation”
Steven Stone, The Absolute Sound
“the excellent separation and spatial precision mean you can dive deep into music just as much as when wearing a pair of full-size open-backed headphones”
What Hi-Fi?
“The soundstage is fairly large, and imaging and layering are solid, though the limited low-end depth slightly reduces precision in certain conditions.”
Chris, The Headphoneer
The consistent weak point, and the one place the objective picture is contested. Sources that push it describe a single small driver running out of headroom: flat, unemotional or compressed when the music gets busy, notes lighter in body than rivals, and audible strain if the bass is boosted. The midrange and treble are exempt — it is the low end and the loud passages that give.
“But the capacity limit shows in the dynamics. The ER4 XR can sound a bit flat and unemotional, occasionally compressed.”
Klaus, Headfonics
“I was disappointed to see rather high distortion in mid frequencies”
amirm, Audio Science Review
“Note can come off as too thin or small in size despite being in your face too.”
iNeroSurge, r/headphones
Measured
Audio Science Review measured high mid-frequency distortion and 'a large jump at 114 dBSPL with the graph changing shape, indicating limiting', plus low sensitivity — 45 Ω and 98 dB at 1 kHz per milliwatt, which is insensitive for an in-ear.
⚠ vs. listeners — The only figures showing very low distortion (0.15% THD) come off Etymotic's own per-unit factory certificate, reported by The Absolute Sound, not from an independent bench. The one independent measurement disagrees, and two listening reviews corroborate it — so the maker's certificate is recorded here rather than averaged in.
Comfort
Contested · 10 srcThe biggest fault line, and a physical one: the ER4XR only works properly when the barrel is seated deep in the ear canal, and people divide sharply over whether that is a week's acclimatisation or a non-starter. The heavier side of the split says it is intrusive — one reviewer had to stop for days from the pain, and the community nickname for the triple-flange tips is unprintable. The other side insists it disappears, and then nothing else competes. Nearly everyone tip-rolls: foam, dual-flange, Comply or SpinFit come up repeatedly as the fix.
Measured
The Absolute Sound puts the stakes plainly: 'The Etymotic ER4 has, since its original inception, been an in-ear that prospective users either love or hate, not because of its sound, but due to its fit.' Etymotic's own page warns that 'Sound quality, full bass response and noise isolation all depend on a good eartip seal in the ear canal.'
Where it splits
A real barrier — invasive, and for some genuinely painful.72%
“For listening, I had to use the foam one as the silicon tips have never fit my ear canal.”
amirm, Audio Science Review
Fine once you acclimate — and then nothing else seals like it.28%
“I finally settled on the triple-flange for both versions because they stayed in place better, requiring far less adjustment after the initial installation.”
Steven Stone, The Absolute Sound
Isolation
Strong consensus · 8 srcThe one thing nobody argues about, and still the best reason to buy it. The deep seal delivers a rated 35-42 dB of passive attenuation; sources independently rate it above active noise-cancelling headphones, and one long-time reviewer rates it above the custom in-ears he has owned. Working drummers use it to monitor at lower volume. The only asterisk is that this isolation is inseparable from the fit half the room can't tolerate.
“Using the triple-flange tips the isolation level of the ER4SR and XR is probably the best of any, including custom-fit in-ears, that I’ve experienced.”
Steven Stone, The Absolute Sound
“As these earphones are non-ported, the foam tips provide fantastic isolation, all-but unbeatable among universal earphones.”
What Hi-Fi?
“Noise isolation is amazing, 35 ... 42 dB with the triple flange tips, they are better than a lot of active noise cancelling headphones.”
florinandrei, r/headphones
Measured
Rated 35 dB with silicone tips and 42 dB with foam. Etymotic notes for comparison that most custom in-ears manage roughly 25-28 dB and foam earplugs up to 32 dB. RTINGS, measuring independently, calls the isolation excellent and says it 'blocks more noise passively than some of the best noise canceling headphones we've tested'.
Build
Strong consensus · 8 srcBroad agreement on both halves of a split verdict. The shell earns near-universal praise — CNC-machined anodised aluminium, tiny and light, a clear generational step up from the plastic ER4P, and expected to survive years of abuse. The accessories are the consistent gripe: the cable transmits footsteps and bumps straight into the ear (the shirt clip helps, routing it over-ear helps more), and the MMCX connector is keyed so most third-party cables simply won't fit.
“Gone is the plastic design. Please welcome an aluminum-built body with replaceable cable.”
Klaus, Headfonics
“you get an extremely well-designed and constructed in-ear that, like the original version, should stand up to any abuse that a traveling audiophile or musician can dish out”
Steven Stone, The Absolute Sound
“However, I do have one issue and that is microphonics. Bumps on the cable are forwarded loudly and directly into the ear.”
Klaus, Headfonics
Measured
Etymotic confirms the cable lock-out is deliberate: 'The cable connector is a customized version of the MMCX. Since it is customized, it is unlikely that other manufacturer's cables will work with the new ER4 models.' The shells are 'anodized aluminum, CNC machined with extremely tight tolerances'; the warranty is two years.
Contested, and along the same seam as the tuning. The launch-era and community sources call it extraordinary — a reference signature and technicalities that embarrass far pricier sets, and Crinacle marks it 'worth the price' at its $350 list. The measurement-led and recent sources counter that near $300 in a crowded market you can buy more consistent sound elsewhere, and that the out-of-box performance needs EQ to justify the money. Both sides agree on what you're really paying for: the isolation and the fit, which nothing else replicates.
Measured
Crinacle ranks it A- overall with a ★ 'worth the price' value rating against a $350 MSRP. Etymotic lists it at $309.99; the most recent review quotes about $299.
Where it splits
Extraordinary — reference sound and technicalities well above the price.58%
“This is an easy recommendation for any aspiring audiophile.”
Klaus, Headfonics
Hard to justify now — modern rivals do more for the money, and it wants EQ.42%
“I can't recommend the Etymotic ER4XR IEM as is.”
amirm, Audio Science Review
