Review: Drop + Etymotic ERX In-Ear Monitors

Drop + Etymotic ERX with case
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In a Nutshell:

The Drop etymotic ERX IEMs (In-Ear Monitors) are wonderful to listen to – when paired with the right kind of audio. They have great clarity, revealing finer details like finger plucking of guitar strings and an unmuffled dynamic range that accurately relay the softest whispers to the loudest screams of any instrument, without losing control.

The exchange for this accuracy is lack of lower bass. What bass you do hear however, is tightly controlled; it never once sounded like a haze of directionless thumping. But since low frequency bass is felt more than heard, it wouldn’t be a total sin (as I make a cross sign across my chest) to utilize an equalizer to pump up the low end a bit.

Noise cancellation is remarkable. It’s passive, but there’s near total silence with Etymotic’s original triple flange. The loud, steady and constant hiss that my heater is making right now… I can’t hear at all. It’s kinda eerie. But no more sitting in the closet or heading to the library for total silence, no sir. You can now sit in a park oblivious to birdsong or be near construction sites without too much bother (though you will feel piledrivers banging the earth and vibrating your bottom. That, nobody can fix.) Etymotic started life specializing in hearing aids/hearing loss (a much more complicated and involved science than is consumer audio), so this doesn’t come as a surprise.

On that note, the ERX should never be used on the road or when walking about. It cuts off all audio awareness of your surroundings; they’re best used for serious listening sessions in areas without oncoming traffic or other dangers.

If you want to hear what high end audio reproduction is all about, the Drop etymotic ERX is certainly worth an audition to buy. Close your eyes and listen; they’ll bring you one step closer to being in front of whoever is singing that song or bringing the audiobook reader’s characters to life.

Full review continued below:


Drop is a remarkable company when it comes to headphones. They’ve already collaborated with big names in Hi-Fi audio like Sennheiser, Focal, and Beyerdynamic. This time, they’ve convinced Etymotic, one of the biggest names in IEMs to co-develop a product they call the Drop + Etymotic ERX.

Thinking back, I remember wanting to try an Etymotic IEM in the mid 90’s after reading a Stereophile review (one of the most respected audio magazines of the time) of the ER-4S. It was the first of its kind, and really intriguing because their pedigree was in hearing aids; they had done more research on (and had more understanding of) how the human ear works than any other company. Their move into consumer electronics would open the IEM floodgates; and the ER-4S would be the first to use balanced armature drivers for the purpose of reproducing music (at least as far as I know).

Fast forward to now. Today we’re gifted with the ERX, Etymotic & Drop’s latest creation; a single balanced armature design with a focus on clarity and accuracy. It’s a solid piece of kit with amazing manufacturing precision that makes you wonder how you ever put up with the junk typically sold at big box stores, like cheap plastic housing, “vegan” leather that falls apart in a few years, parts that don’t actually fit together or sound all that good. The ERX on the other hand? It’s superb quality my friends, that’s what we have here. It goes for both the housing, and the sounds it reproduces.


I was really surprised at the weight of these buggers. They’re heavier than any earbuds I’ve ever used, but I have learned over the years (during my “affordable audiophile” days) that having solid housing is really important for controlling resonance. Cheap materials (typically plastic for headphones/earbuds) adds unwanted color & resonance to the sound vibrations emitted by the drivers, and the ERX minimizes that by using heavy-duty stainless steel. As heavy as it felt however, it was never a bother. You kinda forget they’re there until you yawn or open your mouth in weird ways, which may then require slight re-adjustment for maximum seal.

Drop + Etymotic ERX 3.5mm TRS plug
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As I marveled at the weight in my hand, I flashbacked to a similar experience with a pair of giant-killing shelf speakers; the NHT Superzeroes. They were my first mini-monitors costing $230/pair, whose sound could compete with those costing thousands – and they too, surprised me at first with how much they weighed. No, they weren’t made of metal, but the housing and exterior finish was solid and elegant, just like the ERX is. Both companies seem to share a similar design philosophy for clarity and transparency that I can appreciate.

The choice of shape was interesting and had me wondering. Etymotic uses a slim barrel design for single armature IEMs, and a concha shape for its multi-armature Evo model (a bigger housing, presumably to fit the 3 balanced armatures and 2 crossovers). But a large housing for a single armature… what purpose does it serve? The larger size would mean more metal (higher cost to produce) and more weight. Was there a demand for the concha shape with a single armature… or was it something else completely?

Whatever the case, they put a lot of effort into shaping the concha for a comfortable fit. With the ERX, I felt no discomfort around the housing when plugged in, whereas most competitors slowly introduce you to a world of pain and hurt after only an hour or two because they have no experience shaping for the ear. The over-ear hook design has also saved me numerous times from what would have been very sharp pain. Instead of the IEM getting pulled straight out when caught on doorknobs or various hooks sticking out of walls, it acts as a shock absorber, giving me time to react and ease off.

My first attempts at insertions took practice and some getting used to since Etymotic IEMs go way deeper into the ear canal than anything else I’d ever used. Also new to me were some of the tip designs, which include 6 sets from single to double flanges and one triple flange. The triple flange is an Etymotic classic with great passive isolation from noise up to 35-42dB attenuation (on the ER4 models at least, according to Etymotic), beating out the best that foam plugs are capable of at 32dB.

The strange thing for me was how my head would pulse whenever I used the single flange. It threw me off whenever I’d listen to music because my blood vessels insisted on marching to its own beat while the music followed another. Maybe it was too tight? It soon became less of a problem after realizing that the triple flange blocked out more noise and never gave me the pulsing phenomenon, making the triple my default go-to.

Lastly, the cable is removable. Hooray. I’d like to have seen a thicker cable, but at least it uses the Estron T2 connector for a good, stable connection with IP66 protection against sweat. The other end is an L-shaped 3.5mm TRS jack, making it a 1-way cable for listening only, no mic. I like this for simplicity’s sake (less things going wrong) & the option to switch it out for when my imaginary dog chews it to a pulp.

Drop + Etymotic ERX estron T2 cable
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Oh wait, there’s something else. As I understand it, more advanced users sometimes physically adjust the sound of their IEMs by switching out dampers. The ERX comes with 2 extra dampers that look like tiny tubes with a screen mesh. There’s a filter tool with which you “unscrew” the damper that’s already in place for another one. There’s a whole science to this that will NOT be covered in this review because I have no interest in messing about with all the work Etymotic has put in. For the rest of us, we’ll leave the dampers alone to do its other job of keeping out ear wax.

Drop + Etymotic ERX dampers
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First you’ll need quality recordings to take advantage of these gems. Recordings with dynamic range helps; like opera lets you hear how well the soprano’s voice can project (without purchasing tickets to Lincoln Center.) Um… hold on there chap. Opera? OPERA? What are are you talking about, who listens to opera???

Ok, maybe it’s just me being spoiled as a child of opera singers and a being a former (wanna-be) audiophile. I gotcha, forget I brought it up. Let’s go with Daft Punk then.

The French duo’s “Doin’ It Right” is the only song I’ve found -in my whole collection- that was able to blow me away with a slamming bass line on the Etymotic ERX. While every other song on my player seems to lack bass, this is the one exception. The song itself isn’t very special or outstanding, but the composition has a lot of negative space giving the bass room to showcase itself without being overpowered by instruments or lyrics. Plus, it’s a high-def copy, which I’m sure makes this possible. It was disappointing then that “Da Funk” (a well known track from the same group) didn’t give off as powerful a feel though the composition should have lent itself to the bass better.

In the Eagle’s “Hotel California”, you can almost see the guitar strings being plucked and feel the bongo’s cavity resonate as they’re being thumped at the very beginning of the song. I was really excited when the singing started, but realized quickly that Henley’s voice was being overpowered by the loudness of the instruments. Damn.

With Led Zeppelin’s “Ramble On”, you can clearly pinpoint exactly where everybody is. The rhythm guitar is strumming on a point to your right while Bonham’s tapping a muted tom with his sticks on the left. The bassist starts plucking strings from slightly left of the singer. And after the main guitars are let loose from the far left, a controlled hell breaks loose as the drums power on the snares.

After several hours of listening and getting used to the ERX, you may start hearing weird noises or start looking for some yourself. I thought I heard a burp right at the very beginning of Ladytron’s “Seventeen” as the keyboard beat fades out. I’m not sure, it could’ve been a gulp of a drink, but it was definitely there. It’s something I’d never heard in all my years of having listened to this track. I’m telling you, these IEMs will reveal all; there’s no hiding behind the emperor’s new clothes here, everything’s laid bare for all to see.

On a musical note, “Seventeen” is more dynamic than you’d think. Yes, it’s a lot of synth and electronic drumming ad-infinitum, but you can feel the different levels of sensitivity as the accent voice moves in and out and the computer bleeps at you near the end (3m:47s) as if you’ve stepped on it. Kinda sounds like Flynn’s footsteps during the Discs of Tron jai alai game (00:40m) in the original Tron movie.

By now you probably get the point, but I can’t speak enough on the clarity of the ERX. On Yotoden’s soundtrack “Nobunaga”, what I could have sworn was wailing at the beginning of the of the track was actually reverbed chanting. It was a “holy crap” moment of realization even though I had no idea what was being said (due to my own ignorance of the language used in the chant).

A Kick in the Bass’s Rear

As stated earlier, there seems to be a lack of lower bass. When listening to warble tones (1/3 octave at -20dB), which is to say the sound of actual frequencies, output starts to noticeably diminish around 80Hz and almost disappears at 63Hz. At 50Hz, sound is nearly imperceptible – though to be fair, you can maybe “feel” some vibration. And this was in a silent room with no outside distractions. That said, you can use an equalizer to add extra kick at the lower end if you really want some. Realistically, you can’t demand everything from a single balanced armature and Eytomic has brought out the best of what that armature is capable of.

I personally like to listen at a flat frequency response without any equalizer or surround settings. Each song is different, and I like to hear what the author (or audio engineer I suppose) intended.


Drop + Etymotic ERX package
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As a result of using the Etymotic ERX IEMs, I find myself actively searching for high quality recordings to listen to (and keeping my ears open for goof-ups in them). When you do find them, the ERX will bring things to life, especially with voices and things mid-frequency. Their strong points are bringing out the clarity, dynamic levels and sound stage. It’s not for people who like heavy bass – for that fix, you’ll need to look elsewhere.

Typical MP3s will without a doubt, sound like crap. The ERX will accurately reveal the quality of the recording, whether it’s realistic finger plucking of guitar strings from hi-fi DSDs or the awfulness of that n’th generation copy of AC/DC’s Back in Black encoded 20 years ago by some noob. It’s quite revealing when fire-breathing music can somehow sound dull and uninspired.

But the more you listen with the Etymotic ERX and break them in over time, the sweeter the sound. Two enthusiastic thumbs up!

More Info:
(Test unit provided by Drop for this review.)


Young is a Jack-of-many-trades. He's lived/worked on several continents for all sorts of companies (and has had his own too.) He meditates with origami and likes coffee, though he really should lay off that stuff.

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