Ultimate Ears Reference Remastered

General Information

The successor to the Ultimate Ears Reference Monitors, the engineers at Capitol Studios have teamed up with UE once again to update the reference class IEM.

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CK Moustache

100+ Head-Fier
Link to my review and measurement index thread where one can also find a full review overview, more information about myself as well as my general-ish audio and review manifesto: https://www.head-fi.org/threads/956208/

I only give full stars. My ranking/scoring system does not necessarily follow the norm and is about as follows:

5 stars: The product is very good and received the "highly recommended" award from me.

4 stars: The product is very good and received the "recommended" award from me.

3 stars: The product is good/very good, but not outstanding/special enough to get any of my two awards. ["Thumbs Up"]

2 stars: The product is only about average or even somewhat below that and somewhat flawed/flawed in some areas. [neither "Thumbs Up" nor "Thumbs Down"]

1 star: The product is bad/severely flawed to outright bad. ["Thumbs Down"]

Ultimate Ears Reference Remastered to-go


Review sample.


Three BA drivers per side, three acoustic ways, triple-bore design.

Great to see Ultimate Ears finally offering their CIEM models as UIEMs, especially for those who prefer the fit and handling of universals over customs (myself included) due to not having any fit, seal or positioning issues with most UIEMs.

Came with Ultimate Ears’ new, compact round storage case compared to my UERMs’ large “Roadie Hardcase”. While of high quality, padded on the inside and nicely compact, I wouldn’t mind if it were just somewhat taller as the ear tips can get deformed depending on how the IEMs are positioned inside the case.
Decent unboxing experience.

Good ear tip selection (they appear to be similar to those that came with my UE900 and UE900(S)) and typical accessories such as adapters (6.3 to 3.5 mm as well as impedance adapter) and a cleaning tool. The ear tips could be a bit stiffer, though.

I like the UERR to-gos’ standard design that is clearly an homage to the UERM, but with inverted colours.

Just like on my UERM, I like the transparent inner halves of the UERRs’ shells that reveal the three drivers, crossover components, internal wiring, dampers and sound tubes.
Comparing both, one can see that the driver layout and internal sound channel architecture is different from the UERM which had a dual-bore design whereas Ultimate Ears have opted for three bores on the UERR (most likely to better match the midrange’s and especially treble’s frequency response to the target they aimed for).
What I like as well is that the nozzles’ collars sit further in the back wherefore the ear tips don’t really protrude, which should reduce the acoustic affection that the ear tip material has on the sound to a minimum.

Build quality is very good.

Nicely soft and flexible quad-conductor cable with 2-pin connectors, although ultimately a bit less flexible than the (nicer and more premium looking) factory silver cable that I went with for my UERM.


Largest included silicone ear tips.


Neutral leaning very slightly towards the darker and warmer side. Nearly similar to the tuning of my InEar ProPhile 8. One could also simply say “just like the UERM but with a flat, linear treble without that >10 kHz peak”.

The bass is very flat and extends flat into the real sub-bass without any roll-off, and is slightly lifted by around 3 dB to my ears when listening to music, sine sweeps, noise signals as well as when compared to my Etymotic ER-4S. This leads to just a bit of “body” added to the sound, with an ever so slight spill into the midrange but without necessarily colouring it as the UERR are ultimately still some of the flattest sounding in-ears on the market.

Midrange timbre is mostly correct to my ears, with the upper midrange and presence range being just slightly more on the relaxed side, just like that of the UERM, which gives the UERR a still very revealing but somewhat more relaxed, less “brutally” revealing character compared to in-ears with a more diffuse-field-oriented midrange tuning approach, such as the ER-4S.
That said, what I hear is a still accurate sounding midrange that is ultimately however somewhat closer to a “prosumer neutral” than “studio neutral” tuning, with a slightly warmer and less direct approach in the presence range, but ultimately still very accurate.

The treble is, except for the ~5 kHz range that, just like on my ER-4S and many other in-ears, a bit more recessed than flat-neutral to my ears, remarkably flat, even, smooth and neutral, which also applies to the super treble frequencies above 10 kHz where the UERR sound flat and accurate compared to the UERM that had a peak which added quite a bit of brightness to the sound when a note hit it exactly; extension in the super treble is excellent and reaches past 17 kHz.
Therefore, the treble reproduction and timbre is accurate and realistic to my ears, but, as a result, at the cost of also being less “exciting” or “fresh” when compared to the UERM, which makes the UERR objectively the more linear, more accurate sounding in-ears.

Frequency Response:


Unlike most other in-ears, the UERR to-go showed to be super critical to insertion depth and angle in the coupler, reacting with strong frequency response changes in all areas depending on how they were positioned. The plot above is probably the closest to my actual perception, although with less bass shown on the graph compared to what I actually hear in a side-by-side comparison with my UERM and ER-4S.
The graph below (PP8 compensation) is from the same measurement.

ProPhile 8-Compensation


While the UERR have an additional sound tube over the UERM, it doesn’t show in terms of raw resolution.

Generally, the UERR are mostly similar to my UERM as in having high resolution that is definitely flagship territory, although somewhat below “summit-fi”.

The biggest difference compared to the UERM is in the bass where the UERR, while still having a quick and tight attack with high control, appear a bit softer and with a slightly more lingering, longer decay compared to the UERM, which results in a perception of more “body” at the cost of some perceived tightness.

Midrange details and speech intelligibility are on a high level, and it is rare that one would desire “more”. Speech intelligibility is high.

Treble details are on a high level without faking details with peaks, and the whole presentation is very natural and coherent, with great coherence. While ultimately similar in terms of actual resolution in the highs when compared to my UERM, the UERR definitely have the advantage of sounding more realistic due to being tuned more even here.


The UERR, just like the UERM, will not have the largest soundstage in the range of high-end in-ears. Models like for example the now discontinued UE18 Pro are more expansive and create a deeper, wider and even more layered field of sound. This however doesn’t mean that the UERR have a small soundstage, nonetheless it appears a bit smaller than that of the UERM.

Due to a bit less spatial width than my UERM, the UERRs’ stage appears circular to my ears.

What the UERR can do well is reproducing proximity, and in this regard their soundstage in general appears a bit closer to one’s face than the UERMs’ although both in-ears feature around the same amount of spatial height as well as spatial depth that is definitely well present wherefore the UERR also manage to layer well and create a good imaginary room with quite precisely placed and separated instruments as well as good spatial scaling abilities depending on the recording.

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Ultimate Ears Reference Monitors:

Bass quantity is pretty much similar while subjectively, the UERR appear slightly warmer, fuller in comparison, which is most likely due to the lack of the super treble peak that the UERM have whereas their successors do not. As a result, they definitely sound less analytical.
When it comes to the midrange, the UERRs’ appears closer, more intimate in the mix, with just a touch more perceived lower midrange body while still maintaining a mostly correct, neutral timbre.
In terms of the rest of the treble, both are pretty much similar to my ears, however the UERR do not have the UERMs’ 10 kHz to 13 kHz peak, wherefore they sound smoother, more realistic (“correct”) and more linear in the highs to me, which is a definite plus and, in my opinion, also a rather substantial improvement, however due to that, they are also perceived as “warmer” in comparison and lack that “UERM magic”.

While both in-ear models are on a very high technical level, the UERM appear a bit faster and tighter in the bass compared to the UERR whose lower notes seem to linger just a bit more, which is why they ultimately come across as somewhat tighter, faster and better controlled sounding than their successors that seem to have somewhat more body and decay despite not having any more bass quantity.

Directly compared, the UERMs’ soundstage appears to be somewhat more spatial and wider to my ears, with the UERR presenting the imaginary stage closer to the listener, which makes them appear more intimate.
Layering, precision and separation are pretty much equally good but as the UERRs’ bass appears a little “slower” in comparison, they come across as slightly blurrier/less precise on fast and dense tracks.

As a result, the UERR have an edge over the UERM in terms of tuning because of their more linear, more realistic treble response, whereas the UERM are somewhat above the UERR in terms of technical performance when it comes to bass quality and also a bit when it comes to soundstage, wherefore I would position the UERR higher than the UERM in terms of tuning but somewhat below when it comes to technicalities.

Etymotic ER4XR:

The two in-ears’ sound signature is not exactly similar but still heads into a rather comparable direction.

Both in-ears have got about similar levels of “warmth”, if one wants to call it that, in the root, with the ER4XR being a little more forward in the mid- and sub-bass, making them sound ultimately slightly “bassier” than the UERR.
When it comes to the midrange, the Ety are slightly more forward, with the somewhat closer vocals due to more energy in the presence range, while midrange timbre and balance are comparably accurate.
Both in-ears feature a treble presentation that is among the most even and accurate out there, with the ER-4XR having just slightly less energy with cymbals.
The UERR outperform the ER4XR a bit when it comes to subtle air and extension in the super treble.

In terms of resolution, precision, bass speed and tightness, the UERR appear like the higher-end upgrade to the ER-4XR, with an overall somewhat higher level of minute details and a bit more control.

When it comes to perceived soundstage, that of the UERR is, to my ears, about four times the size of the ER4XR (i.e. twice the width along with twice the depth) and also appears somewhat cleaner and somewhat more precisely layered on complex and dense, fast tracks, with a cleaner and more accurate reproduction of “emptiness” between and around instruments and tonal elements.

InEar ProPhile 8:

Both are tuned remarkably similar to my ears, featuring a “natural neutral” kind of tuning in contrast to the more “studio neutral”-like sound that the ER4SR and my ER-4S have to my ears.
To my ears, the ProPhile 8 have got pretty much exactly 0.5 dB less bass than the UERR and UERM, are slightly less “warm” in the fundamental range/lower midrange, and sound otherwise pretty similar to the UERR in the treble.

In terms of resolution though, I would position the ProPhile 8 a bit over the UERR. The InEars’ bass is even tighter, faster and better controlled in direct comparison to the UERM, and even a bit more so when compared to the UERR, with the generally somewhat higher resolution and note separation, wherefore they have somewhat of an advantage in very dense, fast and complex music passages.

In terms of soundstage, just as with the resolution, the ProPhile 8 are somewhat above the UERR when it comes to imaging precision and note separation with very densely arranged recordings.


Natural-neutral tuning with remarkably linear and realistic treble response.

While the tuning would definitely warrant a “Recommended” award, they are ultimately a bit behind the UERM when it comes to technicalities, especially in the bass that appears a bit softer in comparison (which also somewhat affects the perceived soundstage precision), and then there are the overall very similarly tuned but technically more proficient InEar ProPhile 8, which leaves the UERR to-go “only” as being “very good”, with a “thumbs up”.


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Headphoneus Supremus
Pros: •now finally available as "To-Go" universal fit version
•widely linear tuning
•"Reference Remastered" very fitting name compared to the UERM
•more linear and therefore realistic treble tuning compared to the UERM
•good detail retrieval, separation and realistic imaging
•no "fake" details
Cons: •die-hard UERM fans will likely miss a bit air and sparkle

Originally posted on my German audio review site, the "Kopfhörer-Lounge", here comes my review of the Ultimate Ears Pro Reference Remastered To-Go - yes, the UERR are now finally available as universal fit version!


For an audio lover, there might be some reasons to pick universal fit in-ear monitors over the custom fit variant, such as handling/cleaning/comfort preferences, better resale value or just the preference of how they feel in one’s ears. Whatever it is, there are definitely people who would rather pick the universal fit option if an in-ear was available with custom-moulded or universal fit shells.
I am one of those people (my reason is mainly the handling and that I pretty much never have fit issues with universal fit in-ears), and have encountered several other like-minded people over the years.

For the majority of time, Ultimate Ears’ Pro in-ears were only available with custom-moulded shells – while this fact was not matching my personal preference, I purchased the now discontinued UERM (reviewed here) anyway. They fit very well and seal immediately, but I would have still picked the universal fit option if it were available at that time. And I heard of others who would have done the same and were wishing that Ultimate Ears would also offer their in-ears for sale with universal fit shells, since the more recent universal fit demo models that are available for demo at their partner stores and distributors have got excellent comfort and ergonomics.


Fast forward, Ultimate Ears, who definitely don’t really need an extended introduction since pretty much everybody who is into the in-ear hobby/passion knows them and their story, now offer the UERMs’ successors, the Ultimate Ears Pro Reference Remastered (UERR), as universal fit “to-go” version, which makes me and those other people who prefer universal fit in-ears really happy.

Rather new is also Germany’s new Ultimate Ears partner, “Hearing Berlin”, located in Berlin, who just opened a second branch, “Hearing Dortmund”, located in Dortmund. They don’t only have a full physical showroom where customers can demo the in-ears, but also a laboratory for servicing defective in-ears.

Now how do the new UERR sound, especially when compared to the UERM? That is what this very review is all about.

Full disclosure: The UERR to-go in-ears were sent to me free of charge for this review. As always, my words are nonetheless true, unbiased honest and written without any guidelines or requirements for the review, no matter how it would turn out.

Technical Specifications:

Price: $999/€1229
Available as: CIEM and “to-go” UIEM
Type of Drivers: Balanced Armature, three drivers per side
Acoustic Ways: three acoustic ways, triple-bore construction
Sensitivity at 1 kHz, 1 mW: 100 dB
Frequency Response: 5 Hz – 25 kHz
Impedance at 1 kHz: 35 Ohms

Delivery Content:

I was a bit surprised by how small the delivery box of the UERR to-go in-ears I received for review was, compared to the large box my UERM came with. This is because the UERR in-ears come with Ultimate Ears’ new, compact round storage/carrying case whereas my UERM arrived with the large “Roadie Hardcase”.

Just as with every Ultimate Ears Pro in-ear, one will also find a sticker on the outside that says who the in-ears were crafted for, what’s inside, along with the serial number and the initials of the person who inspected the in-ears.

Inside that cardboard case, one will find a holder for the universal fit silicone and foam tips that obviously come included with the universal fit to-go version, a round, black transport/storage case with the in-ears inside, and last but not least a 6.3 to 3.5 mm adapter, impedance adapter and a combined cleaning tool/brush.

Looks, Feels, Build Quality:

The standard design of the UERR consists of white faceplates with a black UE logo on the left shell and black Capitol Studios logo on the right shell, which is the exact opposite of the UERMs’ design with black faceplates and white logos. Personally I also think that this design option is the best-suited for the UERR, resembling the UERMs’ iconic appearance but with inverted colours, however options for custom colours, materials and designs do exist too and the buyer has got full control over that during the order process, but it’s important to note that then the Capitol Studios logo would be replaced with a UE logo when choosing a different faceplate design than the standard one.

The body of the shells is clear and transparent wherefore one can see the three drivers, crossover components, wiring and acoustic dampers. Comparing the inner layout to the UERMs’, one can easily see that the UERR feature a different driver layout and internal sound channel architecture. This also becomes obvious at the end of the nozzle where the UERM have a dual-bore sound output whereas the new UERR feature a triple-bore construction with each driver getting its own sound tube and output bore.

Quite clever is the nozzle design of the universal fit to-go version, since the collar on the nozzle sits further in the back wherefore the tips don’t really protrude, which means that the ear tip material will have as little influence on the sound as possible.

Build quality of the shells is really good and I cannot spot any air bubbles.

The custom fit version would have two initial letters as well as a serial number printed on the inside of each shell, with red for the right and blue for the left side.

When you order the in-ears, you can choose between various cable lengths, colours, and lately also material. Bluetooth, digital and microphone cable options were recently added as well, along with the option to go with MMCX connectors instead of the proven Ultimate Ears 2-pin connector type.

Not much surprisingly, the black, twisted quad-conductor cable is very soft and flexible (although the silver cable that I chose for my UERM is even a little more flexible), with proper strain relief near the angled 3.5 mm plug, as it should also be expected in the professional and high-end sector.

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The compact, threaded carrying case that is made of metal on the outside and plastic on the inside has got a softly padded lid and bottom. For absolute perfection, solely bolstered or rubberised walls on the inside are missing.

This new carrying case is definitely a nice addition in Ultimate Ears’ line-up compared to the other, larger cases that were offered as only option in the past.

The universal fit to-go version’s silicone and foam ear tips are nicely soft and colour-coded. People who also own the UE900S will definitely recognise them.

Comfort, Isolation:

The fit and comfort of the custom-moulded version will of course highly depend on the quality of used ear impressions, while the universal fit to-go’s fit and comfort will depend on one’s individual ear anatomy.

Shape-wise, the UERR to-go are quite ergonomic and feature a size that should make them fit quite well if your ears are at least averagely sized. In my large and deep ears, fit and comfort are very good and I really appreciate that Ultimate Ears broke with their old tradition and finally offer some of their Pro models, such as the UERR, as universal fit to-go version.

Cable noise is pretty much inexistent, which is due to the over-the-ear fit as well as flexible cable.

Provided you get a properly tight seal with the universal fit version, noise isolation should be about on the same level as when you are using an acrylic custom-fit in-ear, and this also is the case when I compare my custom-moulded UERM to the universal fit UERR to-go monitors that feature a level of passive exterior noise reduction that is very high and just marginally lesser than the custom fit in-ears’.

Neutral = Neutral?

Before I head over to the “Sound” section of my review, I will take a short discourse and look at the theory and research of neutrality with headphones and in-ears and give a very brief introduction to this topic.

With loudspeakers in an acoustically treated room, it is quite easy to define what a measurably neutral frequency response should look like. The case is different in the headphone realm: A headphone or in-ear that would measure exactly like a flat speaker in a raw measurement would sound different directly at the eardrum – this is because our ears, ear canals and upper body amplify certain areas of the frequency range, which is a totally natural and normal thing. With headphones and in-ears, these natural reflections and amplification disappear when the source of sound is directly at the ear, respectively inserted into the ear, wherefore the ear canal is closed on both sides and the “Open Ear Gain” disappears.

To imitate the natural amplification of the lack of this Open Ear Gain, a headphone should ideally show a boost in this area of the frequency response when an uncompensated frequency response chart is viewed (roughly speaking, the boost should be seen between ca. 200 and 15000 Hz, with the climax around 2.7 kHz with an elevation of up to around 15 dB here). Measured directly at the ear drum, this would result in a flat and neutral frequency response (important and related key words on this topic are “HRTF” and “Open Ear Gain”).

Of course the ear anatomy will slightly differ among individuals, wherefore the perception of the averaged diffuse-field target might not be perceived equally by everybody, especially when it comes to the perception of the upper midrange and presence area, wherefore some people might perceive an in-ear that measures flat in the presence area and lower treble according to the diffuse-field target as exhausting or even shrill whereas many other individuals would hear the same frequency response as acoustically flat and neutral. This is rather the exception than the norm though.

Most frequency responses of headphones one can see in magazines and large online sites are therefore usually shown with a compensation target, usually the diffuse-field target, already applied to the raw measurement and show the frequency response that is perceived directly at the ear drum instead of the raw measurement that might be confusing at first if one is used to loudspeaker measurements and doesn’t have much experience with the theory of headphone and in-ear tuning.

Apart from the existence of the Open Ear Gain, there is one thing that has also caused some inconsistency among researchers about what the ideal neutrally perceived frequency response for headphones should be: Listening to music, we don’t only hear the sound waves that reach our ear drums, but also feel the mechanical vibration/body-borne noise with our whole body, especially at higher volume levels. With headphones however, there is obviously no mechanical vibration/body-borne noise anymore, wherefore some people might find a diffuse-field neutral headphone to sound too thin in the lows although a neutrally measuring loudspeaker in a highly treated might not perceived this way by the same person.
Some people and researchers are therefore convinced that the lack of mechanical vibration/body-borne noise when listening through headphones should be compensated by adding a (usually) slight (!) emphasis to lower notes in order to get a headphone to be subjectively perceived to sound equally neutral as a neutrally measuring loudspeaker.

As one can see, the subjectively perceived neutrality with headphones and in-ears is a topic where there is no 100% unity even among famous researchers upon what the ideal frequency response should look like, and of course the individual ear and body anatomy might as well contribute to individual variance although major researches have come to the same conclusion of what the averaged HRTF looks like.


My main sources for listening were the iBasso DX200 (AMP1 module), Cowon Plenue 2, and last but not least the Shinrico SHD5 or my Pioneer PD-S701 connected to my Chord Electronics Mojo & Leckerton UHA-6S.MKII stack.

I solely used the included silicone tips for listening.


The original Ultimate Ears Reference Monitors were already among the more/most neutral sounding in-ears in the high-end in-ear territory, featuring a mostly uncoloured and neutral presentation (with just a tiny pinch of warmth compared to an in-ear that is even closer to the diffuse-field target in the lows, such as the Etymotic ER-4S/SR) with lows that extended flat into the sub-bass, a flat and neutral midrange reproduction, and an upper treble peak that added some extra air and clarity but could sometimes come across as just slightly unnatural and was the UERMs’ only shortcoming.

The new UERR follow this route, being among the more/most subjectively perceived neutral in-ears in the high-end range, but focus on a slightly smoother, more linear approach compared to the UERM, which fortunately also means that Ultimate Ears got rid of that upper treble peak, which, at least to my ears, is a great achievement as it makes the whole presentation even more accurate and realistic.

Their tonality is mostly “flat” and “unexcited”, which is something you want a perceived neutral in-ear to be, although not exactly “boring” or “sterile” – nothing really sticks out, nothing is really masked. Everything in terms of tuning is coherent and nothing is especially highlighted, in contrast to what you would usually find in an in-ear that still sounds balanced but is not tuned for neutrality.

The UERR claim to be studio reference monitors – and they are.

Apart from regular music, listening to white noise and sine sweeps with the UERR is a true delight – no peaks, no valleys, just an overall very smooth, linear and even frequency response with marvellous flatness and evenness, especially in the treble, which is something that definitely not every in-ear achieves. In this way, in the treble, I definitely see an improvement over my UERM that have a peak in the upper highs that makes their presentation sometimes too sharp and artificial if a single note hits that exact spot even if the recording isn’t mastered that way.

In that way the UERR highly remind me of Etymotic’s ER-4 line of in-ears that is around for a very long time and has got, in most parts, a very even, accurate and realistic tuning. Speaking of Etymotic’s reference models, the discontinued ER-4S and its successor, the ER-4SR, there still are some slight differences that can be found in the UERR and are worth to be mentioned. For example in the bass – while the UERR, just like the UERM, are among the flattest and most neutral in-ears in this area, they still have a gentle lift of ca. 3 dB compared to the Etymotic in-ears that are tuned for a diffuse-field neutral bass presentation. Definitely not much and a bit less than the, for Etymotic-standards, somewhat bass-elevated ER-4XR, but still enough to give the UERR just a little more warmth and body in the lows compared to 4S/SR, and to deliver a little of acoustic compensation for the lack of physically felt mechanical vibration and body-borne noise you would get from actual instruments or flat speakers in an acoustically treated room, since the UERR are miles away from being a remotely bassy or even mildly bass-elevated in-ear – it isn’t even “mildly balanced” but quite neutral in the lows and tuned for accuracy and linearity.

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Extension in the lows is really good – just as the UERM, the UERR don’t really have any roll-off in the sub-bass either, but also, not surprisingly at all, won’t give you an impactful, heavy sub-bass.

Midrange timbre is accurate and uncoloured, just as the UERMs’, however the UERR appear to have ever so slightly more body and their vocals seem a bit more present and forward in the mix, with greater proximity.

When it comes to evenness and naturalness in the highs, the UERR deliver a really high level of accuracy and won’t bother the listener with any dips or peaks – just a very smooth, linear, even and harmonious presentation.

Solely the 4 and 5 kHz range takes a slight step back when listening to sine sweeps, just like the UERM, but this area is still more present and neutral than the majority of in-ears on the market that have a dip here to generate a more relaxed middle treble.

The UERRs’ upper highs are where they differ the most from the UERM that had a peak somewhere around 10 kHz. Not so the UERR that are flat here, probably even just a tad too polite with cymbals, and never give you the feeling of too much sharpness but instead realism and tonal accuracy. Too hot mixes are still reproduced that way, but not as aggressively as the UERM (that were however also sometimes too aggressive while no aggressiveness should be reproduced).

Past 10 kHz, in the super treble, the UERR quite easily extend past 17 kHz.

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When there is one thing that I could change about my UERM, it is the upper treble peak that leads to some unrealism and artificiality at times. This is exactly where the UERR come in and deliver almost exactly the upper treble the UERM should always have had in order to be more even and homogenous in the highs. Therefore the name “Reference Remastered” is spot-on and describes what the UERR are – “Reference” in-ears that are based on the UERM but feature an updated, more realistic, linear, “Remastered” upper-end presentation.


High detail retrieval that only rarely leaves you wanting even more is also what one finds delivered by the UERR, just as one already did with the UERM.

Transparency is on a high level without faking details with peaks, and the whole presentation is very coherent and every part of the frequency spectrum appears integrated instead of separated. Here I even see a slight advantage in the treble for the UERR compared to the UERM.

Midrange details and speech intelligibility are on a high level and no part of the frequency spectrum really has an advantage or disadvantage compared to the others; the distribution of details is very coherent.

The bass has got a quick and tight attack and excellent control, however just a bit of added softness in terms of decay to give the UERR a bit more body without affecting control with fast and complex tracks and/or bass lines in any way. Indeed, the discontinued UERM decay slightly quicker and are a bit tighter in comparison, but control is similarly good.


The UERR, just like the UERM, will not have the largest soundstage in the range of high-end in-ears. Models like for example the now discontinued UE18 Pro are more expansive and create a deeper, wider and even more layered field of sound. This however doesn’t mean that the UERR have a small soundstage at all, since this is simply not true.

In terms of width, the UERRs’ soundstage somewhat leaves the base of my head and stops just about one centimetre before where my shoulders’ outer edges are. Therefore it certainly doesn’t lack lateral expansion at all although the UERM carried even a bit more with. This however also means that the UERRs’ stage is a bit more circular compared to the UERMs’ that is a little more oval.

What the UERR can do well is reproducing proximity, and in this regard their soundstage in general appears a bit closer to one’s face than the UERMs’ although both in-ears feature around the same amount of spatial height as well as spatial depth that is definitely well present wherefore the UERR also manage to layer well and create a good imaginary room with quite precisely placed and separated instruments as well as good spatial scaling abilities depending on the recording.


In Comparison with other In-Ears:

Ultimate Ears Reference Monitors (custom fit):

Tonally the two in-ears aren’t even all that far apart – both aim for a quite neutral, reference tonality. Both approach neutrality differently though – the UERM with a slightly cooler, airier character that could be considered “analytical”, and the UERR with a slightly smoother, less “exciting” (in terms of upper treble “bling”) character.

Objectively, both in-ears don’t really differ when it comes to bass delivery – both have got pretty much similar quantity in the lows and root. Nonetheless the UERR appear subjectively slightly warmer and (, which is probably not the right term to use since it not really is what describes the UERR,) “fuller” in comparison, which is because that upper treble peak the UERM had and that gave them their analytical character is gone.

When it comes to midrange, the UERR appear more direct, with more proximity in the mix compared to the now discontinued UERM that have a slightly more distant midrange presentation in comparison. Vocals on the UERR have got just a touch more body compared to the UERM, while still maintaining a correct, neutral timbre and high accuracy.

Where both in-ears differ the most is the treble, and the UERR feature the more realistic (although slightly de-fused) upper treble while the UERM are just somewhat more exciting in the upper highs (at the cost of less accuracy), which leads to a more vivid sound reproduction.

People who loved the UERMs’ tonality to the last bit might therefore miss a bit of sparkle and air from the UERR at the top in the upper treble/beginning super treble, while those who thought that the original UERM were tuned really well but could become a bit too sharp at times at the very top will likely find the sound signature they always wanted the UERM to have right in the UERR. Therefore I would definitely describe the UERR as more correct sounding in the highs, and to my ears the gained realism and refinement in terms of tuning is definitely a plus and rather substantial improvement.

Both in-ears resolve very well, on a pretty much similar level, and have got pretty much similar note separation, too.

The UERM have got the slightly tighter and faster bass in comparison while control on fast and complex tracks is identically good. Due to that, the UERR gain a bit more body and decay, which might be perceived as more natural.

Due to the more even and harmonious treble response, the UERR have somewhat of an advantage when it comes to coherency.

Both in-ears scale well depending on the recording, the UERM probably even more so, which could however also be related to their somewhat more pronounced spatial width in comparison, while depth and height are comparable with the UERR having the slightly closer presentation. Layering accuracy, precision and separation is where the two in-ears are about on the same level.

HiFiMan RE2000:

The UERR are the more linear, neutral sounding in-ears out of the two with somewhat less bass quantity and less warmth in the lower midrange. The RE2000 has got the more impactful bass that, while just around 3 dB more present, appears more impactful and energetic.

The HiFiMan has got the slightly airier/brighter upper mids at the same time (the UERR are flatter and a bit more authentic here), and places them a bit further in the back as a result.

The RE2000 is a good bit more pronounced around 5 kHz where the UERR are just slightly recessed (when regarded by diffuse-field standards and when one is listening to sine sweeps) wherefore the HiFiMan sounds a little more metallic and brighter here.

Cymbals on the RE2000 are splashier but also appear a bit more “spread” instead of spot-on focussed and are a little unnatural.

Generally, the UERR have got the flatter, more linear and correct tuning, but also especially the more linear highs wherefore they sound a bit more realistic and authentic up there.

It is quite remarkable how close the RE2000 comes in terms of bass speed and tightness. The UERR still decay slightly faster, but ultimately bottom-end control is relatively on the same level. Due to the slightly slower decay, the HiFiMan has got that admittedly quite pleasant dynamic driver texture and layering.

When it comes to midrange resolution though, the UERR are a bit ahead and portray the somewhat superior speech intelligibility as well as minute detail retrieval.

Treble separation is almost a draw with the UERR separating single notes slightly sharper with busy and complex recordings. Treble resolution on the other hand is comparable, but as mentioned, the UERR win when it comes to treble realism.

Playing fast and busy recordings, the UERR are somewhat ahead when it comes to control.

In terms of soundstage, the RE2000 features the somewhat wider presentation that is also coupled with a bit more spatial depth, wherefore it generates the more open appearing presentation. Borders around instruments appear slightly cleaner on the UERRs’ side with busier recordings though, and their soundstage also scales better depending on the recording.

Etymotic ER-4XR:

The two in-ears’ sound signature is not exactly similar but still heads into a rather comparable direction.

Both in-ears have got about similar levels of “warmth”, if you want to call it that, in the root, with the ER-4XR being a little more forward in the mid- and sub-bass.

When it comes to the midrange, the Ety is slightly more forward, with the somewhat closer vocals due to more energy in the presence range, while midrange timbre and balance are similarly accurate.

Both in-ears feature a treble presentation that is among the most even and accurate out there, with the ER-4XR having just slightly less energy with cymbals.

Not all that much surprisingly, the UERR win when it comes to subtle air and extension in the super treble.

In terms of resolution, precision, bass speed and tightness, the UERR appear like the higher-end upgrade to the ER-4XR, with an overall higher level of minute details and an increase of control.

I would say that chances aren’t all that bad that if one really likes the ER-4XR but doesn’t mind a slightly flatter lower bass reproduction and a generally higher detail retrieval, that he or she might find exactly this in the UERR. The same goes for those who really like the ER-4S/SR but want a bit more bass than their diffuse-field flat bottom-end reproduction delivers, coupled with the somewhat greater detail retrieval and larger soundstage.

Speaking of the imaginary soundstage, the UERRs’ is about four times as large to my ears (twice the width along with twice the depth) and also appears cleaner and somewhat more precisely layered, with a cleaner and more accurate reproduction of “emptiness” between and around instruments and singers.

So altogether about the same things that I also already found when I compared my UERM to the ER-4SR and my ER-4S.


While die-hard fans of the UERM might miss some of that upper-end air and sparkle, the UERR feature a more linear and realistic treble reproduction, which, in my book, is definitely an improvement as well as an advantage over the now discontinued predecessor.

Should you switch to the UERR if you already possess the UERM? My answer is “only if you found the UERM to be sometimes too sharp around 10 kHz and therefore lacking the last bit of tonal realism and evenness”.

Well done, Ultimate Ears and Capitol Studios. Just as mentioned in the “Sound” section of this review, the UERR definitely deserve the terms “Reference” when speaking about general tonal accuracy and neutrality, and “Remastered” when comparing them to the UERM.


CanJam London 2016 Karting Champion
Pros: Resolving without adding Harshness, Musical yet Transparent, Sensible price.
Cons: Low bass impact at low volume, Pairing with poorer recordings can be hit or miss.
Thank you UE for supplying these review sample and Snugs for the excellent 3D scanned ear impressions.



Never before I have struggled so much to describe a pair of headphones, describing the Ultimate Ears Reference Remastered (UERR) custom in-ear monitor is like trying to describe a bottle of spring water water connoisseurs feel free to grill me on this. It’s natural, flowing and does not impart a distinct flavour to the sound. The UERR shows that driver counts should not be the deciding factor of getting a pair of CIEM.
For those who are looking for a pair of clear and natural sounding CIEM that is often over looked and want a real solid performer at the 1k USD mark, the UERR is well worth looking into.


Transparent, separation and resolution are what the most apparent character when first listening to the UERR. Unlike some detail orientated headphone, the UERR maintain the impressive detail presentation without reverting to boosting the treble.
The UERR does improve with a good source and shines with good recording.

Mids (9.5/10):
To my ears, the vocal of the UERR is the strongest strength of the rather rounded package. Vocal sounds extremely realistic and never drown out by the bass or treble.
Unlike my FitEar MH334, which sweeten and smooth out the vocal, the UERR doesn’t impart any extra flavour the sound but is extremely resolving in the midrange and have one of the most breathtaking vocals that I have heard from a pair of IEM.

Lows (8/10):
This is where opinions can divides. The bass of the UERR extends well, have surprisingly good texture and is lightning fast. However it does not slam anywhere as hard as the competition at the price range. It’s not unlike bass presentation of electrostatic headphones but the slam on the UERR is noticeably lower when stacked up to other in ears, especially when played at a low volume.
The predecessor of the UERR, the UERM have issues lacking in bass, especially outdoors.
The UERR have enough bass to not sound thin and bright in noisy situations but if big bass impact is vital, look elsewhere.

Highs (9/10):

The highs just simply extends and flow, it never shows harshness unless it is already apparent in the source recording. It is unlike the brighter predecessor UERM where the bright treble can be a bit too hot,
If you liked the overall sound of the UERM but the hot treble of the UERM made you looked elsewhere, the UERR should be on your list.

Soundstage (8.5/10):
Another highlight for me, the UERR have a relatively good soundstage depth forward and wide soundstage width for an IEM. It sounds precise and has enough depth to project sound in front, instead of an in-the-head sensation.

Packaging & Storage

Storage with the supplied “hockey puck” case is secure and classy, due to the metal construction it is a relatively heavy case and doesn’t comes with latches but uses an O-Ring to secure the top.

Fit & Isolation

The UERR have great long term comfort and typical isolation for a custom in-ear monitor.
The UERR unit I received is very well fitted. It is shallower fit and overall less tight than my FitEar customs, the looser fitting helps with maintaining a good seal when there is extreme jaw movement. In fact, I wasn’t able to break seal when fitted correctly.
However, the hollow shell on the UERR along with the looser fit does means that while the noise isolation level is higher than most universal in-ears, the isolation is inferior when compared to a fully filled CIEM or silicon CIEM.

Here are some of the characters/features that only might not be apparent in a short demo.
Source scaling (recording to source gear)

The UERR is not a flattering CIEM by any measures. To hear it at its best will require decent recording and capable source gear. I found the UERR sounded best out of the RNHP headphone amp connected to the Chord Mojo acting as a DAC, listening at moderate volume.
It’s not like the UERR will just fall apart when the user’s intention is to just use a smartphone and only really listen to poorer recordings. The transparent character will still shine through but compared to other IEMs that are tuned with a more flattering sound signature will perform better in this usage case.

Small diameter sound bores

Here is a topic that cannot be avoided if you wanted your CIEM to be in top notch condition, cleaning and maintaining!
I personally have easy to clean dry ear wax and not much of it, cleaning is a breeze but do note that 2 of the sound bores are very narrow in the UERR, care must be taken to keep it clean at all times.
The included cleaning kit (wire end) can only fit the largest of the 3 bores and the smaller bores will need to be cleaned out by the included brush instead of the wire tool.

Long listening sessions

As mentioned earlier, the UERR is still a very source dependent IEM compared to other IEMs tuned purely for music enjoyment. The blood of a professional mastering tool stills very much so flows within the UERR.
I found that if listening to well recorded music, the revealing character of the IEM is not an issue but adds a welcoming layer to the listening experience. I can hear details that were not revealed to me before, it is a pleasant experience throughout and it is when the UERR certainly shine the brightest.
However when listening to poorly recorded music, especially when straight out my phone, music sound less dynamic that most consumer focused IEM and flaws are ruthlessly ever so present. Depends on the quality of the recording and the playback chain, it can be a bit tiring to listening to for a long period of time on poor recording. A smooth and mellow IEM will be a better choice in this saturation, if minimal harshness with poor recording is a must.

Similar sounding system

UERR sounds detailed without the typical treble boost that a lot of the more detail oriented headphones tends to exhibit.

Here are some full size headphones that I think that sounds similar:
  • STAX systems, quite a similar presentation to the Lambda.
  • Sennheiser HD800S

The UERR is like a blank canvas, it relies solely on the music that is being played to bring out the colour and will shine brightest when quality recording is played through it. It also scales decently with source components but doesn’t sound bad when played straight out of a smartphone.

At just under $1000USD, it provides excellent value in the current market of CIEM, providing transparency and resolution are what really matters to your listening. UERR shows that getting good sound is not at all about chasing numbers!


FitEar MH334
Fostex TH-X00 Purpleheart
Audio Technica W3000ANV
Audio Technica AD1000PRM

Chord Mojo (Optical In or USB in with UAPP)
Neve RNHP with linear power supply


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