DROP + Etymotic ERX

Ety-heads Assemble!

PROS: Good VFM proposition in its price segment, excellent craftsmanship, build and finish, snug and deep fit, very well-tuned fun take on Etymotic style of reference tuning, good accurate tonality of instruments, good clarity and resolution for the price.

CONS: Not the best upper-treble extension, proprietary nozzle and Estron T2 cable connector not the best for people who like using their favourite eartips and premium 3rd party cables, need a good snug and deep fit to sound its true self.

The product was sent to me free of charge for the review in exchange for my honest opinion.

About ERX Collaboration.

DROP state that their goal was simple – take the community’s most sought-after features from past Etymotic releases and put them into one pair of earphones. The result was a blend of two Etymotic all-timers: the ER4XR and the EVO. From the ER4XR, they took the expressive, ultra-consistent single-balanced-armature design and from the EVO, the in-concha form factor which features Etymotic’s signature deep-insertion build, with a natural shape and next to no protrusion outside of the ear. Tuned together with Etymotic, they say that it has got a sound that sits somewhere between its two predecessors but like to think that its sound is greater than the sum of its parts.

Links – DROP x Etymotic ERX ($249)

DROP x Etymotic ERX Box

Technical Specifications.

  • Drop + Etymotic
  • Frequency Response: 20Hz – 16KHz
  • Transducers: Single high-performance balanced armature per channel
  • Nominal Impedance: 45 Ohms @ 1kHz
  • Sensitivity: 98 dB SPL for a 0.1Vrms input into IEC60318-4 ear simulator @1KHz
  • Maximum Output: 120dB SPL
  • Cable: 4 ft length, user-replaceable, with Estron T2 connectors

Included in the box.

  • ERX Earphone Pair
  • ER T2 Cable with Earhook
  • 2 Dampers
  • Filter Tool
  • Eartips – Single Flange (S, M & L) Double Flange (M & L), Triple Flange (L)
  • Carry Pouch

DROP x Etymotic ERX Accessories

Build Quality, Fit and Comfort.

ERX has EVO’s shells but are made of stainless steel instead of aluminium that the EVO shells were made of. They are very well built and have DROP’s logo on the left faceplate and Etymotic’s on the right. They have a snug and deep fitting fit and form factor like most Etymotics but one that is much better than the violating fit of the tubular Etymotic IEMs. Sadly, ERX too has the proprietary long and slender nozzle of the EVO, which restricts everyone from using and tip rolling their favourite tips since it can only fit the proprietary Etymotic tips. However, you do get single, double and triple flange tips in the package to customise the fit and comfort as per your preference. All in all, ERX is an IEM that has a very secure fit, one that remains comfortable for long hours and can even fit under your helmet without any discomfort.

DROP x Etymotic ERX Solo 2

Cable – I can appreciate Etymotic for designing a better rubber cable than most, one that doesn’t entangle as easily and isn’t too microphonic but I wish they had gone with 2-pin/MMCX connectors over the less popular Estron T2 connectors. I actually like T2 as a connector more than MMCX but it’s more about T2 not being widely adopted and mainly the inability to use the several 2-pin/MMCX premium cables audiophiles generally already own. Otherwise, T2 is actually a better design than MMCX; is highly durable, has no intermittence problem, there is minimal socket wear to last a long time (unlike MMCX), has a stable pull force, has an IP-67 rating and is highly reliable (enough to be used in medical industry).

Luckily, some brands like Effect Audio, PlusSound and Satin Audio already offer T2 (IPX) connector as an option on custom cables. Effect Audio have also now started offering the T2 (IPX) connector in their excellent ConX system (swappable connectors). So, if you own ConX cables from Effect Audio, maybe you already have an IPX (T2) connector in the box or you can email EA and ask if you can just order a T2 (IPX) connector instead of buying a new cable.

DROP x Etymotic ERX Cable

About Etymotic.

I’m sure most of you don’t need an introduction into the world of Etymotic but for those who have been living under a rock – Etymotic is one of the foremost R&D based IEM manufacturers who have been in the industry for close to four decades now. It was established in 1983 with an emphasis on auditory research and engineering-driven product design. Etymotic turned heads just one year later by inventing the first insert earphones for audiological research—the ER1, ER2, and ER3, which are still used in the field today. In 1991, the brand released its first consumer Hi-Fi insert earphone – the ER4, which was the first earphone of its kind to use balanced armature drivers, previously used only in hearing aids. After many years and ER4 iterations, Etymotic released the EVO in 2021, branching out with a multi-driver in-concha design. Through all of these innovations, the brand has stayed true to one signature that’s undeniably Etymotic: earphones that sit deep in the ear canal. It’s an unmistakable, some would say superior design choice and listening experience.

DROP x Etymotic ERX Solo 3

Sounds Analysis.

Summary – ERX is a slight fun take on Etymotic reference tuning and can be categorised as warm-neutral. It has a tastefully tuned 3dB bass shelf, neutral lower-midrange, ~8dB forward upper-midrange pinna gain, smoother lower-treble, a peak around 10kHz that introduces good sparkle and warmer upper-treble post 12.5kHz. All in all, ERX comes across as a very well balanced neutral-warm IEM that will definitely please the hardcore Etymotic fans as well as people who prefer a warm-ish reference sound signature.

DROP X Etymotic ERX

Graphs are measured using an IEC60318-4 (IEC711) setup. You can compare all the graphs on my IEM Graph Database here – Animagus Squiglink.

I can clearly see the ER4XR and EVO inspiration and all they’ve taken and tweaked from both of them. It has around 3dB less of a bass shelf than EVO, fairly neutral lower-midrange like the ER4XR, 2dB less pinna gain (1k-5kHz) than both ER4XR and EVO, and treble that is more like the ER4XR but slightly more in quantity and better balanced in comparison. I’m sure Etymotic fans and people who like reference tuning will see the ERX graphing as an ideal mix of reference, fun and musical.

Drivability (Heads up) – ERX has an impedance of 45Ω and sensitivity of 98dB which makes for an IEM that likes some juice. It can be driven by the average smartphone and laptop but reaches good levels by almost maxing the volume – 80% on OnePlus 7 Pro and 75% on my MacBook Pro.

Let’s dig in deeper…

Bass – 3dB of bass shelf might not seem like a lot but with a reference-ish signature with fairly smooth treble presentation, bass is actually presented extremely cleanly and is quite well balanced. It certainly goes for bass accuracy than quantity but definitely isn’t lacking in any way. Sure, this is balanced armature bass and not a boosted dynamic driver in design, so don’t expect to hear big in your face rumble or slam. If you know what Etymotic generally goes for, you’ll know that this a very tasteful take on neutral bass tuning that favours staying true to the song than boosting and making the bass sound massive and larger than life. It is still a fun take on reference and you’ll definitely be bobbing your head to stuff like Dua Lipa’s ‘Future Nostalgia’ album and other records which have extremely well played dynamic bass lines.

Mids – Midrange is the strongest suite of Etymotic tuning and ERX is no different. It has fairly neutral lower-midrange and a pinna gain peak of 8dB which presents a really good forward upper-midrange with really good tonality of instruments. There is no muddiness in the lower-midrange and that very slightly contour around 500-600 Hz makes sure of it. Vocals and instruments have excellent presence, bite, definition and crunch because of the well executed pinna gain rise and peak.

Treble – ERX’s treble presentation is on the warm side but one that comes off well balanced and makes for good clarity and detail retrieval. Its lower-treble and upper-treble are slightly warmer than what I personally prefer but it is otherwise so well done that you can’t fault it much. Being a single balanced armature, it of course does not have the best upper-treble extension (as you can see in the graph), which was the same case with the ER4XR too. If you’ve heard ER4XR, expect ERX to be fairly similar but with slightly better treble presence in comparison.

Technical performance – ERX has really good clarity and detail retrieval for a single BA and fairly good imaging and soundstage. It is actually quite impressive, unless you compare it to the segment leader – Moondrop Blessing2, another popular reference IEM in this price segment. It falls short particularly in the left to right separation as well as the size and openness of soundstage when compared to the Blessing2, but is still better than 80-90% of other IEMs I’ve tried in this segment.

DROP x Etymotic ERX Tips on Nozzle


– Etymotic ER4XR.

DROP x Etymotic ERX vs Etymotic ER4XR

Graphs matched at 500Hz instead of the standard 1kHz for better comparison.

They are fairly similar sounding IEMs but with some key differences. ERX comes across warmer and less shoutier than ER4XR because of lesser pinna gain (less forward 1k-6kHz). So, instrument bite and definition is slightly pulled back in the ERX, which makes it sound slightly fuller in comparison. Because of this the focus moves towards the bass a bit more and it is the ERX that sounds like it has more bass quantity. The graph comparison was particularly matched at 500Hz to show this more clearly. ERX sounds ever so slightly brighter in treble overall and because of that, ERX sounds slightly airier and better extended than ER4XR, which in turn helps balancing the extra bass quantity and also a bit with better detail retrieval. But on the other hand, ER4XR has more bite and crunch because of the extra pinna gain, so guitars and vocals will come off slightly more forward and stronger on the ER4XR than the ERX. Overall, ERX ends up sounding like a slightly V-shaped, fun and musical take on the ER4XR and that is exactly what DROP and Etymotic had set out to do as per their marketing material.

– Moondrop Blessing2.

DROP x Etymotic ERX vs Moondrop Blessing2

Blessing2 is hybrid with 1DD+4BA whereas ERX is a 1BA IEM. Blessing2 follows Moondrop VDSF target of reference tuning, which actually takes inspiration from the Harman Target research. Even though ERX is being offered at an introductory price of $249 at the moment, Blessing2 will be ERX’s strongest competition at its actual pricing of $300. Sound wise, Blessing2 with its Harman-ish sound signature comes from the other school of reference tuning, which can be seen as more V-shaped when compared to Etymotic’s ER4SR/XR as the reference. Blessing2 has 3-4db more of a bass shelf, a more forward upper-midrange and also brighter treble, with better treble extension up top in comparison. ERX comes off warmer and slightly fuller in the lower-midrange in comparison because of lesser upper-midrange and treble quantity. ERX is less shoutier in the upper-midrange as a result too. Blessing2 has slightly better technical performance out of the two, with a more open, wider and deeper soundstage, better left to right separation and also better detail retrieval. With that said, just know that ERX is no slouch and is quite a capable performer itself, just that it loses against the Blessing2 in my opinion. ERX style of tuning could be more preferable to fans of Etymotic style of reference tuning, whereas the Blessing2 can come off a bit bright in comparison. Another advantage that ERX has over the Blessing2 at the moment is its current pricing of $249, which makes $80 cheaper and that could be a deciding factor for many.


Do I think this collaboration between DROP and Etymotic is a success – yes, definitely! ERX is a very well tuned product that takes the good stuff from EVO and ER4XR, resulting in an IEM that sounds like a fun and musical take on the ER4XR but with EVO style excellent stainless steel shells that have a more comfortable fit and form factor than the regular Etymotic IEMs. What works even more in its favour is that it is cheaper than both the ER4XR and the EVO (significantly). It does face some good competition from reference IEMs from the Moondrop camp but it will definitely impress and work for fans of the Etymotic school of reference tuning. If only DROP could’ve convinced Etymotic to ‘drop’ the proprietary nozzle and Estron T2 connector cable design, it would’ve been an even bigger win for audiophiles, especially those who like cable and tip rolling with premium offerings they already own. Still, ERX is a very good sounding, well rounded product that gets a recommendation from my side!

Gear used for testing and review.

  • DAPs – iBasso DX240 & DX170 | HiBy R5ii | Lotoo PAW6000
  • Laptop – Apple Macbook Pro 15″
  • Phone – OnePlus 7 Pro

Artists I like and listen to.

  • Rock – Foo Fighters, Linkin Park, Switchfoot, Imagine Dragons, Daughtry, Green Day, MuteMath, X Ambassadors, Dave Matthews Band, Vertical Horizon, Our Lady Peace, Lifehouse, Fall Out Boy, Breaking Benjamin, Muse, ACDC, Audioslave, Rage Against the Machine, Biffy Clyro, I Am Giant, Normandie, Paramore, Slash & Guns N Roses, 3 Doors Down.
  • Pop Rock – John Mayer, Coldplay, Paul McCartney, James Bay, Hunter Hayes, Niall Horan, Keith Urban, The Bros Landreth, Bryan Adams.
  • Progressive Rock/Metal – Porcupine Tree/Steven Wilson, Karnivool, Tool, Dead Letter Circus, Periphery, Lamb of God.
  • Pop/Soft Rock – Ed Sheeran, Adele, Taylor Swift, OneRepublic, The Script, Gavin James, Magic Man, Maroon 5, Bruno Mars, Charlie Puth, Dua Lipa, The Weeknd, Oasis, Panic! At the Disco, TwentyOne Pilots.
  • EDM – Chainsmokers, Zedd.

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