25 Years of Making a Good Thing Better: The Etymotic ER4sr and ER4XR

This story originally appeared at InnerFidelity.com

It must have been around 1992 while manning the phone in the early years at HeadRoom that I got an excited call:

"Dude, I just got off an airplane with this guy who had these cool insert headphones. He's a location sound recordist for movies and uses them for their isolation and good sound. I gave them a try...I need a pair badly! Do you know where I can get some Etymotic ER4 earphones?"

It was the first I'd heard of such a thing...or most anybody for that matter. With Etymotic's 1991 release of the ER4S and ER4B, the world received its first commercially available universal fit in-ear monitor. The history of the product goes even farther back to the ER-1, ER-2, and ER-3; the first insert earphones for research and audiology.


The first ER series in-ear monitors for research and audiology had drivers in a separate unit with the sound traveling up narrow tubes to the earpiece.

Etymotic is, and always has been, primarily a hearing health equipment producer making a variety of devices used in research, audiology, and personal hearing safety. The fact that they make excellent IEMs for consumers seems to me more a byproduct of their expertise in the field rather than a strategic goal. They make reference level transducers for the human ear...why not put a 3.5mm plug on it and let people plug it into their player? And boy did that work!

As I recall, when HeadRoom was the only on-line retailer for their products we were selling boatloads of ER4S IEMs and it took all of us by surprise. I'd guess it was nearly 25% of our revenue one of those years.

With the rapid consumption of a first of a kind product, we also heard lots and lots of feedback. "How do I put them in my ears?" "I don't hear any bass." "I've got a good seal but they're still too bright." "Hey, I just pulled them out of my ears and now I've got a tip stuck in my left ear!" "My stem broke." And I kid you not: "My Pomeranian ate a bag of those yellow foam tips from my husband's IEMs and Pookie is in surgery now. WHY THE HELL DID'T YOU PUT A DANGER WARNING ON THE BAG FOR DOGS!" (Um...can your dog read?)

Over the years Etymotic has evolved the ER4 in numerous ways. A variety of tips have evolved and Etymotic is generous in providing users with a numerous options for a personalized fit. Housing material and integrity has been improved for better durability. The tuning has change over the years, generally with a warming trend through the models. (More on this later.) As a result, Etymotic now has an entire line of IEMs that descend directly from the original ER4 to serve the needs of a variety of consumers from kids to smartphone users, and for those on a budget to audio pros and audiophiles.


Etymotic ER4SR and ER4XR ($349)
These new Etymotic IEMs show ample evidence of their 30 year evolution. The value proposition is extraordinary here; these new IEMs pack in a lot of performance at this price.

These are single balanced armature receiver IEMs with a deep insertion fit. The body and stem are now anodized aluminum for improved durability. Tips fit over the stem very securely. Filters are fitted into the end of the stem, and spare filters and removal tool are supplied.

The cable is just shy of five feet overall with 14" of Y-split. The main cable has a very nice feel to it, quite dead feeling and lays flat nicely without tangling. The Y-cords are thin twisted pairs and lay down around the ears easily. The adjustment slider moves smoothly on the cables and is appropriately secure once set. The Y-split is accomplished with a vary nice anodized aluminum cylinder. The cable is terminated at the player end with a rubber molded near-90 degree angle 3.5mm TRS plug. Plug body is narrow near the connector allowing it to fit through smartphone cases. Ear piece cable ends are terminated in an angled MMCX connector with rotational position detent. A shirt clip is provided.

I find this an excellent cable that easily takes a proper position and feels comfortable when worn up and around the ears. My only comment is that it would be nice if Etymotic offered a version of the cable with a remote/mic on it for headset use.

Accessorization for these is simply outstanding. The IEMs come with a fairly large, hard-sided, clamshell case. Also included is: an assortment of tips; 3.5mm to 1/4" adapter; filter removal tool and replacement filters; and a shirt clip.

My only comment here is that the case is fairly large and likely too bulky for every day use. It would have been nice if they included one with purchase, but Etymotic does make a small zipper pouch for $4 that would be handy for every day carry of the IEMs alone.

Comfort has always been an issue with Etymotic's deep-insertion IEMs. It's not their fault really, it's the nature of the beast. Deep-insertion IEMs seal the entire front half of the ear canal, ideally to the bony section of the ear canal. There, the skin of the ear canal grows directly on bone. Sealing the IEM there does a couple of good things:

When an IEM seals at the entry of the ear canal, it creates a volume of trapped air between the entrance and ear drum. Because the first half of the ear canal is fleshy it can vibrate with mechanical input—like with foot-falls or chewing on something crunchy. As the ear canal vibrates it slightly changes shape, and with changing shape its volume changes slightly, which causes the ear drum to move in and out to compensate for the changes in air pressure with volume change. This is called the occlusion effect, and it is why you hear your voice louder when you plug up your ears.

With a deep insertion earphone having a tip that seals at the bony section, you don't have as much change in ear canal shape with vibration resulting in a significant decrease to the occlusion effect. With an Etymotic earphone properly inserted you get less noise from your heart beat, breathing, foot-fall, or your own singing along...if you're into that sort of thing.

It also improves isolation from outside noise. Related to the occlusion effect above, when you plug the outside entrance of your ear canal outside sound will still vibrate the flesh around the ear. This vibration will be coupled to the ear drum through the occlusion effect. With a deep-insertion earphone sealed at the bony section, isolation from outside noise is essentially at it's maximum possible. There does remain some sound that gets to the ear through bone conduction, but there's nothing you can do about that short of clamping your skull in a vice.

Bottom line: With Etymotic deep insertion IEMs you get the lowest noise floor and highest isolation possible.

The down side is sticking something that far into your ear can be quite uncomfortable. Fortunately, Etymotic has over the course of the last 20 years developed numerous tips; spend some time trying them all out and you'll almost certainly find one that's reasonably comfortable. The best solution, however, is to get some Custom Fit Earmolds, which provide a significantly more comfortable fit than generic tips.

User Notes
Couple quick random but worthy notes:

  • The earpiece dimensions have not changed and custom tips made for any of the previous ER4 series will fit the ER4SR and ER4XR.
  • If you own a pair of ER4B, ER4PT or ER4S IEMs, you can upgrade to one of the new models. Price is $225 or $275 depending on whether your pair is within the 2-year warranty period and whether you have proof of purchase. Details here.

Alrightythen, let's turn the page and talk about sound quality.

Etymotic Research, Inc.
61 Martin Lane
Elk Grove Village, IL 60007