Drop + Etymotic ERX IEM Review and Measurements

Etymotic needs no introduction when it comes to IEMs. They were around during the early days (before most of you kids in 2022 obtained sentience) and a proponent of their "diffuse field" target. The ER-4S, pictured below, can arguably be called the HD600 of the IEM world. If you didn't own one, you at least heard one, most likely being able to borrow a friend's ER4S for an extended period of the time.


ER-4S with triple flange deep penetrator tips.

The ER-4S was finicky. Most complaints revolved around it sounding too thin, having too much emphasis around the pinna gain region 2-3kHz, and having a small spike in the treble. The secret to using the ER-4S was super deep insertion, usually with the treble flange penetrator tips. Naturally, most people did not like the feeling of having their ear holes penetrated so deeply.

Now what seems like 15 or more years later, the folks at Drop have collaborated with Etymotic to make a new version called the ERX for people who did not want their ear holes assaulted. There's now a normal IEM body instead of a phallic tube. In addition, a set of tips is included that provides a good seal with a good tonal signature (that is not lean or spiky in the highs). At least for me it did. FWIW, I did try the triple flange tip and could not get it to work properly because the body of the IEM prevents deep insertion. Anyway, why did it take so long?


Drop + Etymotic ERX IEM

I would have to say that this is the most agreeable Ety yet to my ears. There's a good amount of bass that extends low. It's not overdone. Of course tastes and gear references vary, thus I can see many IEM users wanting moar bass, moar upper-mids, more treble, a la the Harmon Curve, which this community on average happens to somewhat disagree with (or vehemently disagree when comes to its IE target).

It would say, take the stock ER-4S tuning, lift the bass a bit, lower the highs a bit, and keep the 2-3kHz bump. The 2-3kHz bump is slightly too much for my ears, probably because my pinna amplify this region more than what Ety expected. IEMs bypass pinna, so inverse HRTF curves will never be perfect. However, things were not so far off that I wasn't able to acclimate after a few songs.

 

Drop + Etymotic ERX IEM
Frequency Response
(SBAF compensation)


Compared to other IEMs, ER4s, and GAudio Nair (considered by most here on SBAF to be the IEM with the most accurate tonal signature / frequency response)

Drop + Etymotic ERX IEM (blue and red)
Ety ER4SR (grey)
Frequency Response



Drop + Etymotic ERX IEM (BLU and RED)
GAudio Nair (GRY)
Frequency Response

 

Drop + Etymotic ERX IEM
Distortion vs Frequency at Various SPL (at 1kHz)


We can see tight grouping of the 3rd harmonic. This is a balanced armature (BA) driver. Sometimes I wonder if a darker frequency response slope is better for BA type IEMs. I know some people find BA type drivers grating. I sometimes do myself. I did not find the ERX timbre annoying at all. There was another Drop BA IEM that was dirt cheap that was tuned similarly dark which I also did not have any issue with.

 

Drop + Etymotic ERX IEM
Impedance (GRN) and Electrical Phase (GRY)


Nominal impedance is 45-ohms, rising to 60-ohms at 10kHz. Higher output impedance will lift the highs slightly, not much.

FWIW, one thing I really like about the Etys is that they are NOT super sensitive. This allows us to use tube amps or high-gain (which usually sounds better). I had no problems with a Vali 2+ on high-gain.

Pretty sure this will be possible. Asking right now.

 

NOT. Typo.

 

Will have to defer to @shotgunshane since I never got ears on Ety's DD 2 series. I wouldn't say these are the most dynamic or explosive. The ERX's strengths are cohesiveness and relaxed tuning. It's still an ER4 series, but with different tuning, and a more agreeable housing and optimized tips so that deep insertion is not necessary. The ER4S(R) in comparison is more bright monitor, like a vintage NS10 without any toilet paper in front of the tweeter. I think the treble will be smooth enough to most ears. I can still pick out the inherent peak in the highs, but it's more difficult because the highs are shelved down just a bit.

 

My review unit was just delivered today. After I post a review, I’ll send it on a SBAF USA tour.

The ERX is essentially an ER4XR in an EVO housing with slightly different tuning. I was an early proto tester and can say that earlier unit was indeed tuned a little different than a regular ER4XR (warmer, smoother) but I’m not sure what has changed since then. I haven’t opened the production unit just yet. I’ll have comparisons with the ER4XR, ER-4S and an ER2.

 

Will see if I have time. I'm tempted not to try the filters because the EXR have a relaxed sound already. Don't want to tune them like Audezes.

Indeed and I'm glad you pointed this out. ERX is dark, but it isn't rolled. Highs are more evident than the FR graphs would indicate. However, the ERX does lack last octave air to my ears.


Drop + Etymotic ERX IEM (CYA)
Ety ER4SR (VIO)
Ety ER4XR (GRY)
Frequency Response



ER4XR is an ER4SR with slightly more bass.
ERX is an ER4XR is toned down highs.