Review: IMR Acoustics IMR-R1

IMR Acoustics R1

IMR-R1 – Direct link to information

Purchase B-Stock – B-Stock purchase if available

A Little Technical Stuff:

  • 13mm driver featuring Neodymium motors with beryllium diaphragm + Ceramic driver
  • IMR Open and close porting system
  • 5 Audio filters
  • 2 Pin detachable cable
  • Impedance: 32 Ohm
  • Sensitivity: 108 +/- 3DB
  • Frequency response: 14 – 40000Hz
  • 24ct Gold plated 3.5mm Jack
  • 4M length OFC cable
  • Hard Case
  • 5mm Adapter
  • Huge selection of ear tips for the perfect fit


  • Black – Maximum attack with powerful impactful bass, rich mids, and controlled highs
  • Pink – Slightly decreased bass from the black filter with the same mids and highs
  • Copper – Maximum bass, lush mids, and slightly recessed highs
  • Orange – Balanced bass and mids with rolled off highs
  • Blue – Beautifully balanced across the range, natural and airy sound with perfect mid and sub-bass.

IMR Acoustics IMR-R1

-MRSP: Universal fit £500.00 GBP/$663 USD at the time of the review

Sometimes available in B Stock – (currently £299.00 GBP – $397 USD)

I want to thank Bob James, proprietor of IMR Acoustics for providing me with the IMR-R1 for review.

Bob has been known in the industry for quite some time due to past affiliation with Trinity Audio. Bob’s company, IMR Acoustics, is a UK based company. The IMR-R1 is his current companies first go-round with an IEM and I will say they have made quite a royal splash, UK-Royal, get it? The IMR R1 has price positioned itself in the middle of the IEM tiers unless you are able to purchase a B-Stock which is quite a terrific bargain. However, while they may have priced themselves in the middle tier their sound quality can marginally compete with some upper tier offerings. I find the IMR-R1 has a great sound to price ratio.

I am not generally the person that has a lot of patience for “tweaking” sound, I guess I am more of a plug and play person. The IMR-R1 has taught me that experimenting with various filters and open/closed port combos were fun and worth the experimentation. In the end, I was able to find my sweet spot with an open port and the pink filter, but I also will say I enjoyed the default black filter almost equally as well.

The IMR-R1 is not without faults, as I will touch on later, but sound quality and the ability to engage the listener is not one of those faults.

A one sentence summary would be, the first offering from IMR Acoustics is a worthy listen.

A Little Marketing Hype:

The R1 is unlike any other universal in-ear monitor available on the market today.

Experience sound like never before with beautifully textured bass and lush midrange and highs that are present but not harsh.

Tuned to perfection using IMR’s custom 13mm Ceramic hybrid driver unit. With its specialist hi-res ceramic driver combined with a beryllium 13mm dynamic driver with powerful neodymium motors for a huge soundstage and precise instrument placement and with an FR from 14-40000Hz to cover the whole audible range of audio.

Unlike other manufacturers using ceramics in this market that require high power to drive their units ours only needs 32 Ohm!

However, the R1’s abilities do not stop there! The R1 also incorporates a switchable open and close port on the rear of the in-ear monitor to allow you to change the staging and shut off the outside world when required. In addition, the R1 is supplied with 5 audio filters to allow you to tweak the tuning to your individual style. These audio filters allow you to alter bass levels, treble levels and increase midrange as required.

The First Switchable Open and Close Port

The IMR R1 uses a unique switchable open and close port on the rear of the in-ear monitor, allowing you to change the staging and acoustic levels and shut off the outside world whenever you choose. This innovation is easily recognizable in quiet environments and is exclusive to the R1.

Fully Customize Your Experience

The IMR in-ear monitors are supplied with 5 acoustic audio filters allowing you to tune your IEM’s to your individual taste. These audio filters enable you to alter bass levels, treble levels and increase midrange to suit your personal preferences.





  • 5mm to 6.3mm adaptor
  • A semi-hard shell, zippered carry case,
  • 5mm cable
  • Eartips out the wazoo
  • IMR-R1 monitors
  • Filters and more filters
  • Shirt clip

Unboxing and Accessories: 

The accessories are plentiful. There are no cutesy items like wiping cloths or bags but the accessories that are included are exactly what is needed. A semi-hard, zippered carry case, ample ear tips in a variety of different styles and sizes and the sound filters. Originally a 2.5 balanced cable was included with the 3.5mm cable but the 2.5mm cable had issues and the decision was made to only include the 3.5mm cable. After the 2.5mm balanced cable was redone and issue free, I asked Bob if I could receive one and was promptly sent one. I have a 2.5mm and a 3.5mm SE cable, both being stock. I cannot think of anything else I would want as an accessory to further enhance my experience for that matter.

The explanation of the filters and what they attempt to achieve is listed above. The IEM’s are threaded as are the filters, so one must only unscrew whatever filter you are currently using and screw in one you would like to switch to. Very simple! Each and every filter is distinguished by a different color. The only issue is the fact it is difficult to decipher which is the orange and which is the copper, copper is the darker orange one, maybe green or some other color not so close, might have been a better choice.

I tried all of the filters and finally settled on the pink filters. I will say that “settled” may not be the correct choice of wording because out of my three favorite all seemed to be the “right one” at various times. I found the black(default), copper and pink to be my favorites. Keep in mind this is only my preference and YMMV and probably will.

Eartip wise, I decided on the JVC Spiral Dot L tips. They provided me with the best overall experience. I received a great seal and bass response and well as comfort with the JVC tips, and overall the best sound.

Now for the elephant in the room, the cable. Frankly, the cable sucks. It is rubber coated,uncomfortable, unruly, springy cable with a weird connector, to add to that, the cable doesn’t always want to stay behind the ears. The connector is a 2-pin so what could be so wrong? The pins insert into the IEM at an angle making it almost impossible to find one of your existing cables that will work. I hate the cable ergonomics and how it connects.

The cable should not enough deter anyone from buying the R1, as a matter of fact, I have worse cables in my collection, the Dita Truth, a $500 cable, has worse ergonomics. The sound of the cable is adequate, but the fact that it has a mind of its own is disturbing. The cable ergonomics do improve a little over time. In one of the online forums there are many folks mentioning that they have found aftermarket cables that provide comfort and fit inside at the angle and that they have fallen completely in love with the R1 with an after-market cable.

Build and Quality and Fit:

The IMR-R1 is quite an industrial, almost military looking IEM with metal screws and a brutish metal open/closed port dial. The R1 is neither large or small, the housings have a certain heft with its aluminum shell. The dial on the face of the housing is the main focal point as it is large and industrial with a notched edge. The bright chrome dial is designed to twist to give you either an open or a closed IEM depending on your environment. The nozzle itself is medium in length but extends further due to the fact that the filter threads into the nozzle end. The design is almost three pieces with the dial being one and both sides of the housing being two and three. The housing itself is a gunmetal color but with the huge dial being bright chrome it gives the illusion everything is chrome. On the side of the housing closest to your head, the monitors are labeled identifying the L and R and an IMR logo is emblazoned on the outside of the housing. The dial had some imperfections in the metal, I am usually very critical of imperfections but these have such an industrial design I wasn’t bothered.

The build quality is solid in its metal housing. I am sure they are not indestructible but they certainly have a feeling that they will be your companion for the ages. The only thing I question may be the threading where you insert the filters. Inserting and removing with time can cause the threads to become stripped and cross-threaded. These are only ramblings and possibly unfounded worries. Also, after initially playing around with filters you will more than likely settle on a filter that satisfies you and not swap them often. Also, remember the IMR-R1 has a three-year warranty.

A little more on the open/closed port dial. While it is a nice option, I found there to not be a staggering difference in sound quality between the open or closed position. Possibly, there is a bit more air in the open position but to me, it is not a huge night and day difference. It is subtle more than drastic. Also, the difference in isolation from outside noises is minimal.

Overall, I have zero-real complaints with the comfort of the IEM. They are about in the middle of the pack as far as comfort is concerned. I have had torture devices and some IEM’s I barely knew were in my ears and these are somewhere in between, if it weren’t for the cable, ugh! The nozzle has a slight upward tilt which happens to work well for my ears.

The IMR-R1 is a hybrid driver design utilizing a dual driver design. One being a beryllium13mm driver and the other a ceramic driver said to be a hi-res ceramic driver. I had no problem driving the IMR-R1 with any of the sources I have in my collection with the impedance being 32 ohms.

While I am not disturbed by driver flex I know many folks are and I want to tell you that driver flex is present and can be quite strong, especially upon insertion.

Review Setup:

This review was written utilizing multiple sources, Opus #2, LG V30, QP2R and Opus#1S.  I listened using both a 3.5mm SE and 2.5mm balanced connection. I mostly utilized the pink filters and JVC Spiral Dot ear tips. My sample music consisted of 320kb and FLAC as well as streaming Tidal Masters, Spotify, and Deezer.

Moving on to the sound section….

The IMR-R1 is one of those IEM’s that comes out of the box and just smacks you into reality from the start, and it is a Godsmack. The default filter is the black filter and the R1 immediately begins to impress you with its prowess. It is a rich, snappy, bassy, with a up front and center aggressive sound. The R1 commands your attention and I admit it did get my attention. The IMR-R1 is not a smooth, Cohiba and Cognac type of IEM, not a warm, inviting s’mores around the campfire listen.


To effectively articulate the presentation and overall sound signature I would begin with aggressive, fast, furious, snappy, gritty and unapologetic. There is a tremendous amount of energy and snap in the signature. As I have stated I am using the pink filters which I felt had the most impact on bringing out the positive attributes and taming the most negative attributes. The R1 does not do much to try to tame music files that are prone to sibilance or harshness and to me it’s sharp aggressive delivery of the highs is one of the few negatives I can mention. The positives are without a doubt are the incredible bass that envelopes the listener and makes for a toe-tapping, head bobbing experience. An example of some of the music that will showcase the speed and presentation of the R1 would be EDM or specifically the likes of Infected Mushroom. That genre of music has a lot going on within the music and the R1 also seems to deliver at a frantic pace so they match quite well. While my description may conjure a manic display the R1 performs with the same level of intensity across the spectrum, so it delivers quite a balance. If you want immersion, play YYZ from Rush and take in all of the fast and furious bliss that the R1 is capable of. The R1 is an incredibly capable IEM.

The soundstage is very large and very well defined. Geometrically, It would be a large cube as it presents itself in more of a 3d fashion than a square. I think the fact the clarity of this IEM is superb lends itself to the encompassing feel that there is so much air around the notes. It certainly has one of the largest stages I have encountered.  Worth mentioning is the fact that to my ears the entire delivery is so in your face. When listening you can forget feeling you are two or three rows back from the stage, with the R1 you are exactly at the stage. I feel even with the pink filter everything is in your face, and some of the filters make this effect more pronounced.

I would classify the tonality and timbre to be average. The R1 has showcased other qualities in which it excels but the tone and timbre have a slight metallic sound, and those characteristics are placed mid-way through the list of specific qualities pertaining to the R1, with instruments sound ing realistic but their timbre being off. I am highlighting what I hear, but I do not wish to sound as if there are any glaring defects that would be considered deal breaking. I think the fact the treble extends so darn well really overshadows any artificial tones. The delivery is not spastic or out of control, in fact, I find it very controlled it is simply the tuning of the R1 and I feel Bob is presenting us the music exactly as he intended to.

Each frequency range is clear, defined and well presented. Nothing bleeds or interferes with the providing you with clear definition. While there is a strong, snappy bass presence there is no real feeling of warmth or smoothness. Some adjectives that would not describe the R1 are lush, smooth, warm.


The bass is the driving force of the R1 and clearly, it is my favorite part of the signature. It is a thunderous yet fast, snappy bass. The sub-bass kicks with a jaw-rattling force, especially with the copper filters. The Red Hot Chili Peppers, By The Way, is a delightful listen to get a feel for the intensity of the bass. What the heck, anything by the Red Hot Chili Peppers and Flea is awesome with the R1. The bass in the R1 is proud of its weight and it flaunts its girth without any loose or flabby notes. It is crisp and defined, to say the least. I am a huge fan of Dynamic Driver bass and the R1 certainly carries on that DD tradition. All of the bass frequencies are clearly represented and accounted for. Definition and resolution of the bass notes are what you can expect while having a serious impact that the listener can feel as well as hear. I feel the pink filter may decrease the sub-bass somewhat. There is a sharp decay and you won’t find any lingering notes. The bass of the Dita Dream is still at the top of the heap of the DD’s I have heard, based at the time I received the R1, but this would certainly be a close second and first in terms of impact with the Dunu DK-3001 also thrown somewhere in the mix.


Depending on the filter used, the mids can be very front and center. I think the pink filter is a little less aggressive than some of the others. The pink filters may produce a slight dip in the lower mid-range. There is no decline in the amount of clarity or details in the mid-range and as previously mentioned the separation is huge. Possibly, because the pink filter appears to slightly lessen the sub-bass it creates the illusion of increased clarity and detail. There is nothing analytical or fatiguing about the mid-range of the R1 in that it is not the most micro-detailed but the clarity is phenomenal. There are adequate details revealed but you won’t have fatigue over long listening sessions due to an overabundance of detail. To me, some of what you can achieve from the mid-range is going to be based on the music you throw at it. Meaning, the R1 has a capable mid-range and if the music is complex and detailed then that is what you will hear.


This is the part of the signature I wrestle with the most.  The treble extends well and has a very aggressive shimmer. The treble certainly aids in producing the awesome soundstage and delivery of details but yet there is something metallic to me in the tone. It is not really a natural timbre and I think that is part of the perception of the in your face highs. They say perception is reality and to me, that is the reality, I enjoy the overall IEM immensely but I cannot effectively articulate my feelings towards the treble without sounding negative. Nothing is truly offensive here nor would I say that the treble is troubling but it is the weakest link to the entire signature. I am hesitant to say the R1 is a bright IEM because I found balance with the pink filter. The copper filter appeared to lessen the treble a bit more but I enjoyed the extension and width the pink filters provided me. As I said before if you have music that is sibilant the R1 will do nothing to smooth out the rough edges. You can expect details and clarity and I am being critical, because I love how the treble creates a balance and harmony throughout the entire range. Some of the sources, such as the Opus #1S, with its smoother tone and rich full sound, helped cure what I feel ailed the R1. Listening to Dire Straits Sultans of Swing, the cymbal hits can be a touch overbearing.


The R1 doesn’t need a great deal of power to drive but with some extra power, it will certainly excel. It is an IEM that realizes the sweet spot between well powered and underpowered, meaning that I found its aggressive nature to be fatiguing with too much power, just overbearing. I want to say that I have tried to become more volume conscious lately as I am trying to preserve my old ears and hearing. I have found that while it is really enjoyable to bump up the volume on occasion it probably isn’t the best for the hearing. I know it is not an earthshattering bulletin that loud noise damages hearing but it is becoming my reality.

All of my sources drove them perfectly fine and while most of my sources have a more neutral to slightly warmish profile, except maybe the Shanling M3S, I found it is indeed the neutral to warmish signature that works best for my needs. I would say that tone and organic sound might be what you should seek in a DAP to find your ultimate pairing.

My least favorite pairing of the sources I utilized to write the review would be the LGV30. I did not feel it provided the tone and body that the aided in smoothing out the rough spots with the R1.

My favorites were the Opus#2, Opus#1S, and the QP2R. The Opus#2 has a slight edge because of the warmth in its signature. The Opus#2 is very organic and has been my reference DAP for quite some time now. As I will mention in another review, it has been replaced as my reference by the QP2R but I still found the Opus#2 to be a slightly better pairing with the R1. The stage remains immense and the slight warmth, in all of the right places seemed to mesh so well with the R1.

The Opus#1S has such a full, rich sound with a very cozy tone that it was really a match made in heaven for the R1. It lacks a little resolution that the Opus#2 offers but the pairings tonality is truly hard to beat. For the $600 difference between the Opus#2 and the Opus#1S, with the 1S being the less expensive, I do not think you can go wrong with this pairing. For $400 for the Opus#1S and a B-Stock R1 for around the same price, it is quite a formidable combination.

To you QP2R owners or anyone considering the QP2R you will not be disappointed, but I found that the amount of power the balanced output delivers, you can easily listen at lower volumes. The sound is not quite as warm, as the slightly warm tilted Opus#2. That said, to me a touch of warmth is better with the IMR-R1 so I give the nod to the Opus#2 with this pairing. The QP2R does, however, provide a big, full concert hall sound.


Yikes, comparisons are super tough with the IMR-R1. Firstly, you have so many tuning options between the open/closed port and the array of filters. Secondly, they are at a price point new that I don’t have anything to compare and B-Stock it is one of the best IEM deals around and again I have almost nothing in this B-Stock price range.

I will provide a comparison between the DUNU DK-3001, which is a DD hybrid, and $500 and the FIBAE 2 at $560.

DUNU DK-3001 vs. IMR R1

This is an interesting head to head. I love most everything about the DUNU-DK3001 except for the medieval dungeon torture device style fit that the DUNU employs.

The sound of the DUNU is smoother in its delivery and no way near as in your face as the R1. Soundstage wise the R1 is certainly the king but the DK-3001 is no slouch, I find the R1 stage to be one of the best I have heard. I would like to say, in general, I really enjoyed the signature of the DUNU, I had no sound issues. I equally enjoy the R1 and I do feel it is a better IEM by a nose.  Partly, because you have more tuning options and partly because it has a superb overall clarity.  My critical points are more when I dissect the frequencies as opposed to what it brings to the table as one cohesive IEM.

The bass in both is incredible, with the R1 being a touch more present and snappy. They both deliver nice bass layering and clarity, Dunu is smoother and the R1 is crisper. The overall tone may be more natural with the DK-3001 and I prefer its tuning and tonality to the R1. I generally like a smoother tuning than an aggressive one. The R1 is extraordinary in its clarity and how it digs into the song and extracts the detail. Neither IEM are detail monsters and they confidently leave the analytical sound to others on the market. Treble is abrupt in the R1 and smooth in the DK-3001. I think by now you get the idea. Personally, you can’t go wrong with either, for me, I give the nod to the R1.


The soundstage is displayed differently between the two IEM’s, both are incredibly wide but the R1 has a more 3D geometry. The F2 is a fun, musical IEM with a warmish signature. The warmth of the F2 is so welcomed. The R1 is more detailed and direct with a higher level of clarity than the F2. The F2 adds a richer, lower mid-range with the R1 having more resolution and clarity in its mids. This showdown would more depend on the mood of the listener. As previously stated, I like smooth and warm. However, once you plug in the R1 and hear the bass snap and the how the sound all comes together you quickly become a believer.

Two different moods, but with the tuning options I would find myself grabbing the R1 more than the F2, even though the fit is better with the F2 and its warm tuning to make it a tough choice I would give a slight edge to the R1.

Sorry, there are not more comparisons I just could think of any fair comparisons that I have in my possession.

In Closing

IMR Acoustics is a new kid on the block, the owner is not. Bob has been the topic of drama from the Trinity days, but I can only speak from my own experience and it has been stellar. This is not an attempt to sway anyone’s thinking, it is merely my experience. Responsive responses, great service, quality first product, again overall stellar.

The ability to tune the sound to your liking is pretty incredible with the open/closed port dial and the tuning filters. Without a doubt, you can find something that strikes your fancy.

The build is an industrial inspiration and heavy duty but not uncomfortable in contrast to how it looks. I think they are built for the long haul and heavy duty.

The sound caught me by surprise. It kicks some serious butt! I know the overtone of this review appeared negative referencing bright and aggressive but everything comes together so darn well. The frequencies all blend and the sounds have an incredible synergy. There is oodles of clarity and resolution.

Bass is incredible, snappy, with little decay and it is always present. The bass never interferes with the other frequencies.

The cable really is not good. If I was asked to make one improvement, the cable is hands down the weakest part of this product. The sound quality of the cable is fine but the unwieldy ergonomics and the fact it doesn’t like to stay behind your ear makes it a challenge to like.

If you want validation for your purchase or a recommendation, consider this both. It is a terrific addition to the collection or if it is your only IEM, you can feel confident you have made the right choice. Enjoy!