Etymotic Research ER4S Review

Etymotic Research ER4S
Reviewed Nov 2009

Details: Legendary IEM from Etymotic Research, first released more than a decade ago MSRP: $299.99 / manufacturer’s page Current Price: $299 from  Specs: Driver: BA | Imp: 100 Ω | Sens: 100 dB | Freq: 20-16k Hz | Cable: 5’ L-plug Nozzle Size: 3mm | Preferred tips: Shure Olives, Etymotic tri-flanges Wear Style: Over-the-ear or straight down

Accessories (5/5) – Large selection of silicone and foam tips, plastic storage case, carrying pouch, two sets of spare filters, filter removal tool, ¼” adapter, and shirt clip
Build Quality (4.5/5) – The tubular are made out of a thick, sturdy plastic. Stock cables are thick, strong, and – if necessary – replaceable
Isolation (4.5/5) – Very deep fit. Etymotic claims a maximum attenuation of 42db, and I believe them
Microphonics (3.5/5) – Can be microphonic when used without the included shirt clip. Hard to wear over-the-ear due to long stem and thick cables
Comfort (4/5) – Have to be inserted quite deeply for ideal seal. The thin housing makes this easier and Foam tips often work great

Sound (9.2/10) – There is just no way not to be blown away with the level of detail these things put out. Unlike the RE0, which let the detail sink in slowly, the Etymotics smack you in the face with it. As a result, they can be very unforgiving of poor source material, as a good studio headphone should be – these are not for collectors of low-bitrate mp3s. The highs are detailed and extended, replete with mind-boggling crispness and resolution. The mids are smooth, detailed, well-placed and very engaging. Tone is neutral and the overall balance is excellent.

The bass has great detail but tends to be a bit thin of note. The ER4S is not bassy by any means, but definitely satisfying for those in search of quality over quantity. Bass texture is superb. The presentation is typical Etymotic – excellent instrument separation, good layering and positioning, but not much in the way of 3D space.

Amping: Not required but will go a ways towards making them shine with portable equipment. Though an mp3 player can drive them to decent volume, it will not unlock their full potential. With a decent amp (such as a mini3), the ER4S really opens the tap on speed and detail.

Value (8.5/10) – Make no mistake – Etymotic’s flagship is still a top-tier IEM 15 years later. The fact that the ER-4S costs $300 to some of the other flagships’ $400+ is a testament to its high value, not low worth.

Pros: Some of the most detailed sound to be had, durable, replaceable cables, unbeatable isolation, 2-yr warranty
Cons: Deep insertion not for everyone, can be difficult to wear over the ear, microphonics can annoy without shirt clip, very analytical sound


  1. Hey! I’m interested in your opinion of the ER-4Bs in comparison to these (if you’ve tried them).

    I’ve seen comments floating around suggesting they’re at least as good as the ER-4Ss for music. Would they be that much better than the ER-4Ss for binaural audio anyway?

    I’m trying to decide between these two – for use with both binaural and regular recordings. Getting both is an option but I don’t want to if the difference is marginal. How are the ER-4Bs for music, and how are the ER-4Ss for binaural?

    • Sorry, binaural recordings are really not my area of expertise and I’ve never tried the ER-4B. From what I remember Etymotic themselves do not recommend the B for music use (the S gets enough complaints of having too much upper midrange as is) but you might want to shoot them an email and see what they have to say about it these days. Last time I saw the 4B mentioned was years ago.

  2. Do they play well with EQing around? for EDM/Rock?Metal music ?

    • They can take some EQing as long as you’re not trying to radically change the sound. They will never be basshead earphones, but if you’re just trying to sculpt the response a bit here and there to suit your needs, no problem.

  3. Hi Joker,

    Love your work! Right now I have Westone W40s, but the fit is driving me crazy — one keeps falling out. Have been through all the different tips, Complys, etc. So have been thinking about Etys again, perhaps the fit will do me better. I don’t really crave the Westone warmth — last thing I had was RE400 — but do worry about output level a little. I use IEMs for iphone, and don’t want to lug an amp around with me. Do you have any thoughts on output difference between ER4s and W40s? Or any other commentary? Thanks!

    • That’s an interesting question because the ER4S and W40 are pretty much the opposite extremes when it comes to sensitivity/efficiency. The W40 is well above average while the ER4S is one of the least efficient IEMs.

      Rough guesstimate, I’d say you need at least 50% volume headroom on your iPhone, meaning that if you normally use your W40 below 50% volume you should have enough room to compensate for the lower efficiency of the ER4S.

      There is also the newer ER4PT. If I’m not mistaken, it also comes with the 4S adapter, which means you’re getting the best of both worlds.

  4. Hi Joker! I’ve had the HF5/HF2 for eight years now, and I’ve just sent my last pair back to Etymotic for the special purchase pricing (cable had a split originating at the jack). I can replace my HF2s for around $80, or get the ER4 for around $180. Do you think that the step up in sound will be meaningful for a $100 difference, especially considering that I will be using them with a Sansa Clip+ without amping?

    • It’s quite a small difference, but par for the course in the diminishing returns land of higher-end audio. You never get double the performance, or anywhere close to it, for double the money. If I were you I’d skip the upgrade, but I’m sure some would disagree.

  5. I’m pretty new to high-end IEM’s and these look really nice to me. What I don’t understand is what does “these are not for collectors of low-bitrate mp3s” mean? I mostly listen to music on my iphone and my macbook and i listen to a whole range of genres, will they not be good for me? Wouldn’t you want analytical sound?

    • What I meant is, balanced and accurate headphones like these make it easiest to pick up on things like compression artifacts in low-bitrate mp3s and poor mastering in general. If you have a lot of those types of tracks and don’t want to hear that stuff, get less revealing headphones.

      • What about the Etymotic Research ER-4PT?

        • The PT is identical except the cable has ~75 ohms less resistance. The sound is very close between the two but the ER4S has always been recommended as the more accurate one, so it’s the one I’ve stuck with.

          You can go from the PT tuning to the S tuning by adding an inline impedance adapter.

          • The ER4-P is the unequalized version of the ER4. This gives it a lower impedance that makes it play somewhat louder with a bass boost on lesser lower powered players or amps that have a lower voltage at the headphone output. Adding the “S” cable wild add a passive equalizer network in the cable that flattens the frequency response but also raises the impedance of the earphone so it plays at lower volume and needs more amplification for a louder sound. One can buy a set of ER4 and can have it both ways. I have had numerous sets of the ER4 over 20 years and am amazed it is still around and is still a standard for me and obviously others as well regardless of what else is available. I have purchased a few expensive custom IEMs for high dollars and was nothing but disappointed after having lived with these for years. If you are looking for good sound you can’t go wrong with these. Even the lower bit rate mp3s will sound as good as they can and there is no point in trying to gloss that over but rather to learn where the limit of different mp3 levels are and compress accordingly. A mp3 encoded at a high bit rate will hold up very well with the best playback equipment and sound great with the ER4.

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