artnoiNov 11, 2025
Never imagined myself writing consumer review for a 10 year-old in-ear monitors. But the Etymotic ER4SR is just too good to not have it in my digital footprint. My descendants will be proud of me, for the love I have for this pair of little ear dildos.
If I can only have 1 pair of earphones for my whole life, that will be Etymotic ER4SR. It singlehandedly killed my 2016-2017 passion for hunting for headphones/earphones, simply because other stuff was no where nearly as good or acceptably priced.
This is my tribute to one of the best engineered products from an engineering-first companu, the only one to do so in the bullshit ridden consumer audio space.
I like music, and I want to enjoy it with as much fidelity as possible (i.e. transparent). Normally, most parts in an audio chain are transparent, even the cheap ones.
For example, the Apple Lightning Dongle and MacBook outputs are considered transparent enough for driving its intended load.
The 3 points are my top 3 requirements for an audio system:
I have access to the music library (solved)
I have transparent audio devices
I have transparent enough drivers
Extra points if I can verify the gear performance from independent measurement, or salute to the manufacturers who publish these results objectively and professionally.
Bonus points if it’s also portable.
Despite owning several “monitors” and non-monitor headphones/earphones, I still feel like something’s off. It’s like each of my other monitors will sound good overall, but lacking or having some problems in some frequency range.
Then one day I walked into a Seoul audio shop, and happened to see a weird looking barrel-shaped Etymotic ER3 models on shop stand.
I suddenly remembered that I’ve since always seen it on audio forums since maybe 2011, and that people call it “too flat” or “too dry” but still the best reference. I demoed the unit right away.
The first one I tried at the shop was ER3SE, and boy was I blown away. It sounded right in every region - the bass, mid, and highs, and it’s very cheap too. It also sounded like my HD600 but with fuller sound across the spectrum.
And after having had tried the ER4SR, I bought it right away (at the time, I could barely tell the differences between ER4SR and ER3SR due to ear fatigue).
Well it turns out, a lot of things.
In fact, let’s first compare the FR of ER4SR with my other “reference” grade custom monitors and see how the ER4SR handles ear gain with grace compared to whatever UE’s doing:
Very, very flat sound
Although engineered for decades already (ER4SR was released circa 2016, developed from earlier ER4S, which in turn was developed from the original ER4), no other IEMs come this close for sounding so boring for such a long time.
Being designed by the folks who make hearing-aid and first in-ears, it’s so surprise that the ER4SR sounds so damn good. It sounds good because of its transparency.
You’re almost listening to the music itself and not to the drivers. This is why I call the Etys “boring” in the sense that you almost forget about the monitors had they not penetrating you that deep.
Transparent bass
The bass response is superb. It’s not boosted, but it’s still flat down to 20Hz. That makes the bass very high quality, and you could hear everything including the lowest bass frequencies. People who say the Etys lack bass simply crave boosted bass response, and they don’t even know that their boosted bass is masking the lowest sub-bass.
I also have another pair of IEMs (custom too, in fact) that has some what similar looking flat bass performance: the 3BA UERR+.
Note: my UERR+ is a different model, not UERR as measured in the link above. However, they should sound close, considering UE did not even bother to put up a big marketing efforts for it.
Compared to the much more expensive (\(1000 customs vs \)200-310 universals), the ER4SR holds its own pretty well but still lacks the energy and details in lower frequencies. This might have to do with ER4SR’s single driver being stressed out, but who knows.
Natural mids, with proper ear gain
Because Etymotic knows about the ear amplification effect, they factor this phenomenon into their engineering process. The result? Excellent flat midrange that sounds very natural as if it comes from outside of the ear.
Compared to my CIEM UE RR+, which measures flat at the eardrum (does not factor in this ear amplification effect), the ER4SR mids are not muffled or laid-back, whereas the CIEM sounds like so despite it measuring flat.
Tonality wise this is the best sounding mids I’ve heard. Not too powerful, not too loud, not muffled - it’s just right.
Boring highs (good)
Highs are just right. No piercing and not rolled off. Not sure what’s more to say about this, I’m getting old, so let’s just say it’s not problematic and transparent enough for you to stop thinking about the trebles.
Certificate
Every box of ER4SR comes with a paper certificate hand signed by a human. The cert covers frequency response of both channels, and THD in %. Of all the monitors I’ve bought, only the ER4 family.
US designed, made, and binned (before 2025)
Etymotic has some serious QC pipeline that allows it to match both ER4SR channels to within 1dB.
The 2nd pair I bought in 2025 was made in Vietnam, but still comes with the certificate. Not sure where they measured the VN lot though.
Accessories
You’re for Right to Repair? If so, the Etys are for you. ER4SR comes with 2 sets of any type of tips included. Assume we have 5 types (yes they include that many), then we have 10 tips included.
The box also includes the replacement filter and high-quality metal precision tool to service the tiny earphones.
And this earphones include 2 cases! One rectangle hardcase and a smaller pouch.
Durability and longevity
THe ER4SR is designed for longevity. MMCX cables are replacable, so are the tips and internal tubes. It’s designed to last and be serviced.
I’ve stepped on the ER4SR once, droped it to concrete once, and there’s not a scratch on the barrel. After 7 years, my original pair of ER4SR is still going strong, except for broken cable. The cable broke because I wore them over-the-ear, though it’s designed to be worn normally. That puts extra stress on the cable and cause it break.
In fact, it’s because the cable broke and the replacement cable are somewhat pricey that led me to buy a 2nd pair in 2025.
After getting a 2nd pair, I can confirm that my original pair still work like it’s new.
Superb support
Etymotic replies my emails within 1 business day. I once accidentally put my ER4SR through very high volume (wasn’t listening) and was afraid I broke the drivers. Etymotic replies right away with technical information that basically just says “your pair is ok not fried).
After the assurance, Etymotic offers me to send my pair back to them to verify that it’s still good I did not, simply because I trust them
After 7 years, I asked them about replacement cables, and they replied right away. Last week, I contacted Etymotic asking them about new version of tips I included in the Vietnam version, and they gave me solid and detailed explanation.
Compare this to UE who not only misses deadlines but also not replying to any of my emails (they will direct me to my Thai dealer instead). UE fails to ship date, and when the date came, failed to notify me that the deadline was extended for 2 days after the deadline.
Due to current geopolitical climate, I’m not sure if we’ll be able to buy these fantastic ER4SR in the future. Which is why I bought the 2nd pair - to horde it for myself.
Owning a 2nd pair also combines their accessories to the point that I’ll not run out of tips within 10-20 years. And when I’m paranoid whether I’ve clogged the sound tubes, I can just use the other pair to confirm. If you gotta have reference, why not have 2 references?
In fact, after getting myself a custom UE RR+, I’ve been wanting to buy a 3rd pair for girl from Drop.com because $200 is such a great deal.
Although I know that there’re competent Chinese companies making in-ear monitors scientifically now, I still want to celebrate Etyomotic’s pioneering spirit.
TLDR; It’s just that good. Buy before US implodes.