IMR Acoustics R1 Review

IMR Acoustics R1 review



IMR Acoustics is a relative young UK based brand, which was founded by Bob James with the main goal to create an In-Ear monitor that sounds like an electrostatic headphone, airy, detailed and with a wide soundstage.

IMR Acoustics Official Webpage:




The IMR Acoustics R1 In-Ear Monitor was provided to me by IMR Acoustics as a review sample. As always, I am not affiliated with IMR Acoustics or any third person beyond this review and these words reflect my true, unaltered, opinions about the product.


The Price:

The IMR Acoustics R1 is available on IMR Acoustics Webpage and is sold for around $665.00 USD under the following link.

Purchase link:

Warranty: IMR Acoustics is offering a 3 Year Limited Warranty


Package and Accessories:

The IMR Acoustics R1 came in a rectangular red card-box, which is wrapped with a black cardboard cover that sports the IMR acoustics logo and is containing the following items;

  • 1 pair x IMR Acoustic R1 Monitor
  • 1 pcs x Oxygen Free Cooper (OFC) 2 pin cable
  • 3 pairs x Gray Silicone Ear Tips (S/M/L)
  • 1 pair x White Silicone Ear Tip (M)
  • 2 pairs x Foam Ear Tips (M/L)
  • 5 pair x Sound Tuning Filters & Metal Filter Holder
  • 1 pcs x Hard Case
  • 1 pcs x 6.5mm Adapter
  • 1 pcs x Shirt Clip



Design and Build Quality:

The IMR Acoustics R1 is a unique and robust looking In-Ear Monitor (IEM) with a quite different design language. We can divide the IMR R1 into three parts; the main housing, which is made of an CNC machined aluminum chassis with gunmetal paintwork, the sound switch port, which is in silver color and also made of silver painted metal and the interchangeable tuning filter system.

The Main housing sports two screws, the 2pin female connector and left right markings.  The sound tuning port (also described as rotating port) sports a markings (“C” for closed and “O” for open) that shows if the switch is in open or closed back mode. They are 5 sets of sound tuning filters that are all in different colors (black, blue, orange, copper and pick), which I will explain later.

The overall build quality is pretty solid, but it doesn’t looks premium like some other competitors in the same price class.


The Cable:

The IMR Acoustics R1 sports a detachable cable with 2 pin connectors that have a diameter of 0,78mm, which are more common than 2 pin systems with 0,75mm diameter. This 2 pin connectors have metal insertions that give a robust appearance.

The cable itself is made of an OFC (Oxygen Free Copper) wire material that has a tick and protective TPU coating.

The cable length is 1.4m and the 3.5mm 24ct gold plated headphone jack has a L angled profile.

This cable sports also a plastic chin slider and a metal Y splitter.

My first complain comes to the direction choice of the 2pin male connector, which makes the use of third party upgrade cables a bit problematic. My second complain comes to the thickness of the cable which is normally a good thing regarding to the protection, but which is a bit annoying if you try to wear the R1 over the ear.


Fit, Comfort and Isolation:

The IMR Acoustics R1 can be categorized as IEM of the larger side, because the solid aluminum housing is pretty big, but doesn’t feel heavy when inserted to my ears. It should not be problematic for ears with an average size like mine.

The IMR Acoustics R1 normally is fairly comfortable, but the cable is a bit annoying due its stiff and thick nature, which is causing to irritation after a while. I have found a solution, when you wear over your ear with the help of an ear-hook, the comfort issue disappears completely. Bad that IMR Acoustics didn’t have included a set of ear-hook to the package.

The Isolation is above average and there is no noticeable or better to say dramatic change, even when the rotating port is in open position.



About the Hybrid Driver Unit:

The IMR Acoustic R1 sports a custom made 13mm diameter Ceramic hybrid driver unit. This ceramic driver is combined with a 13mm dynamic driver that has neodymium motors, which supports a frequency range between 14- 40000Hz to cover the whole audible range of audio.

According to IMR Acoustics; the ceramic driver inside the R1 is not as power hungry like the competition and has a relative low impedance of 32 Ohm.

As mentioned before, the R1 also incorporates a switchable open and close port on the rear of the in-ear monitor to allow changing the staging or isolating from the world outside 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 response as required.



Technical Specifications:


  • Driver Type                : 13mm driver featuring Neodymium motors with beryllium diaphragm                                      + Ceramic driver
  • Sound Porting            : IMR Open and close porting system
  • Impedance                 : 32 Ohm
  • Sensitivity                   : 108 +/- 3DB
  • Frequency response  : 14 – 40000Hz
  • Headphone Jack        : 24ct Gold plated 3.5mm Jack
  • Connector Type         : 2 Pin detachable cable
  • Cable Type                 : Oxygen Free Cooper (OFC) Cable


Drivability (Impedance):

The IMR Acoustic R1 is a relative easy to drive In-Ear Monitor with a rated impedance of 32 Ohm’s and there was only the need of extra volume with the orange and cooper filter.

This feature makes the R1 ideal for the use with portable sources like Smartphones, Tablet’s or DAP’s with a relative weak amplification.



a) In Ear Monitor : IMR Acoustics R1, Campfire Audio Polaris

b) DAP/DAC : Cayin N5II, Chord Mojo, Hidizs DH1000, Fiio Q5

c) Albums & Tracks used for this review:

  • Jehan Barbur – Yollar (Spotify)
  • Minor Empire – Bulbulum Altin Kafeste (Spotify)
  • London Grammar – Interlud (Live) (Flac 24bit/44kHz)
  • Laura Pergolizzi – Lost On You “Live at Harvard and Stone” (Tidal Hi-Fi)
  • Steve Srauss – Mr. Bones (Flac 16bit/44kHz)
  • Dire Straits – Money for Nothing (DSD 64)
  • Gothart – Jovano, Jovanke (Spotify)
  • Otto Liebert & Luna Negra – The River (DSF) – Binaural Recording
  • GoGo Penguin – Fanfares (Tidal Hi-Fi)
  • Adam Taylor – Colour to the Moon (Flac 16bit/44kHz)
  • Casey Abrams – Robot Lover (Tidal Hi-Fi)
  • Liquid Tension Experiment 2 – Acid Rain (Spotify)
  • Opeth – Damnation (Tidal Hi-Fi)
  • Megadeth – Sweating Bullets (Flac 16bit/44kHz)
  • Metallica – Sad bu True (Flac 24bit/96kHz)
  • Future Heroes – Another World (Tidal Hi-fi)
  • Lorde – Team (Flac 24bit/48kHz)
  • Tom Player – Resonace Theory “Album” (Tidal Hi-Fi)
  • Deeperise feat. Jabbar – Move On (Spotify)



Sound Analysis and Comparisons: 

a) Short Description of the Sound Filters according to IMR Acoustics:

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


PS:  I have burn-in the IMR Acoustics R1 for a approx 150 hours due the Ceramic Hybrid configuration, which should need more time to show its true potential. I have used the stock gray silicone ear tips, which came inside the package of the IMR Acoustics R1 and the filter in pink color will be my reference filter.


b) Sound Signature and Tonality:

As I mentioned before, the IMR Acoustics R1 has a wide variety of sound tuning filters that can drastically change the tonality and frequency response. The user has the possibility to choose one of the five filters supplied according to his taste.

IMR Acoustics R1 provides a warm, neutral, energetic, full or vivid tone signature and presentation through the filters. Since there is a radical sound difference between the five filters, I will try to compare it with each other.


The Pink Filter:

The Pink filter has a linear bass emphasis and sounds fast, energetic and detailed. It’s very natural with percussion instruments such as drums etc. to be used in metal music. The overall speed and detail representation is quite successful.

The bass amount of the Pink filter will probably not be sufficient for bass heads in music types such as Pop or EDM, but is quite enough for natural instruments. The bass has a good depth display, but the extension is a bit shorter than the other filters, such as black and copper filters.

The midrange of the Pink Filter sounds very balanced, clean, energetic and transparent. Instruments sounding very lifelike and the level of detail reproduction is above its price range.

Vocals are successful and the tonality is pretty natural. The coloration level is very low and the lower midrange sound more balanced than the copper filter.

Female voices have a pronounced emphasis on the upper midrange and sounding spacious detailed and vivid.

The treble of the pink filter have good extension without any remarkable ear piercing. Some Instruments such as woodwinds or bells sounding crisp, detailed and lively.

The only noticeable considerable distress is that the treble sounds sometimes metallic and slightly cold. Otherwise the heights are technically successful.


The Black Filter:

The black filter has the most coloration among all filter and has a V-shaped sound signature. The lower frequency range is dominant and the treble is less detailed compared to the pink filter.

This filter shares a deeper and more dominant lower frequency depth; moreover the bass is more controlled and has a good decay. It’s superior in terms of quantity and depth to the Pink Filter, but can not keep up with its speed.

In the Black Filter, the instruments are slightly positioned in front of the vocals and the male vocals can sometimes mix. However, I have not found such a situation with female vocals. The midrange of the Black filter sounds colored, warm and bright, but the Pink Filter has more detail to offer.

The sound on the black filter is tuned for comfortable listening, but is missing some energy and liveliness, when it comes to the treble presentation. The treble extension and sharpness of the black filter is behind in performance and don’t sounds as airy and clean like the pink filter. In short, the black filter is slightly lacking in airiness and for the brightness, but is an ideal filter for long listening periods.


The Copper Filter:

The Copper Filter has the highest amount of bass among all filters and is perfect for Bass-head’s. This filter is superior in terms of bass depth and amount to the black filter, but the bass presentation dominates the R1 presentation to a high degree.

Although the copper filter is more successful in terms of bass amount, depth and extension than the other filters, but the speed and detail reproduction is inferior to the blue and pink filters.

The mid-range sounds fuller, thicker and shares more body than the black and pink filter. But the mid-frequency region is not as detailed and airy as the pink and blue filters. The most salient feature that is forgiving while listening to female voices.

The treble range of the copper filter is less detailed and forward than the pink and black filter.

While the treble detail could be enough for bass heavy genres, it may not be enough for other genres. The copper is less successful in terms of airiness and spaciousness than the Pink filter, but don’t get me wrong, it doesn’t sounds completely airless.


The Orange Filter:

The orange filter has the warmest sound signature among all filters and sounds thick, full and controlled.

The bass amount and depth of the orange filter is inferior to the copper filter, but superior to the blue and pink filter.

The midrange of this filter sounds more spacious and detailed than the copper. The midrange has also a wider volume than the copper, but the detail reproduction and separation of instruments is inferior to the pink filter.

The treble of the orange filter has the less airiness and extension, and is also suitable for long listening periods.


The Blue Filter:

The blue and the pink filters are the most balanced sounding in this collection. The blue filter has a relative linear and neutral bass character, but is inferior to the pink filter in terms of bass depth and emphasis. This filter is especially suitable for music types that require a high bass speed.

The midrange performance of the blue filter is slightly behind the pink filter, but is superior to the rest in the collection. The midrange sounds pretty neutral, lively, clean and spacious.

Although the midrange is a bit more backwards compared to the pink filter and the

Vocals are not as accentuated as the pink filter. But if we compare it with the rest of the filters it sounds more detailed than all the others.

The treble range of the blue filter is slightly behind the pink filter in terms of extension, sharpness, control, speed and detail, but is superior all other filters.

There are no negative situations like sibilance or mixing and the airiness and freshness of the treble range is also remarkable and successful.

As a result, the IMR Acoustics R1 offers its users a wide range of sound filters, which we could descript as vocal, bass, linear, musical and reference filters.


f) Soundstage:

The IMR Acoustics R1 has in general a relatively large soundstage for an In-Ear Monitor and spreads the instruments pretty well over this stage. The R1 is performing slightly better regarding to depth, but please don’t get me wrong, the wideness of the stage is also pretty good at all.


g) About the Switchable Port:

It is possible to use the IMR Acoustics R1 in open or closed mode, thanks to the wheel pointing to points ‘O’ and ‘C’ on the back of the IMR Acoustics  R1.

In open mode, the IMR Acoustics R1 has a larger bass range, especially with the blue filter, but the amount of bass decreases. In closed mode, the bass gains more in speed, depth, volume and emphasis than in open mode.


The Comparison:

Vs. Campfire Audio Polaris

Both In-Ear Monitors have similar price levels, while the IMR R1 has the advantage to change the sound signature and detail level, which can increase or decrease depending on the selected filter.  The Campfire Audio Polaris is generally neutral and has a slightly dry and lively presentation.

The bass lines of Polaris are fast, energetic and accented and will be sufficient for most users except Bass-head’s. Polaris is more successful in the amount and depth of the bass than the black, pink and blue filters of the IMR R1, but shares a slightly lower performance than the copper filter.

The bass of this two IEM’s is pretty fast and controlled, but the speed of the blue filter makes the IMR Acoustics R1 superior to Campfire Audio Polaris.

Both In-Ear Monitor’s are sounding fairly lively and clean midrange. The detail performance of the IMR Acoustics R1 with the pink filter is superior to the Campfire Audio Polaris, while the Polaris performs better than the R1’s copper and orange filters.

The midrange of the Campfire Audio Polaris sounds recessed, while the positioning of the midrange is variable depending of the filter that is used.

Both IEM’s sharing a vibrant, well extended and detailed treble presentation. The detail in the treble range is a slightly better with the IMR Acoustic R1 especially with the pink filter, while the Polaris offers a better detail reproduction compared to the orange and copper filters. Both, the IMR Acoustics R1 and the Campfire Audio Polaris are sharing a good performance in terms of airiness and control in the treble range.

The IMR Acoustics R1 has a slightly deeper and also wider soundstage presentation than those of the Campfire Audio Polaris, while the Polaris has the upper hand for soundstage height.



The IMR Acoustics R1 is a very capable and flexible In-Ear Monitor with its unique sound switch port and very effective sound tuning filters. This flexibility and the detail level, which is on a level above its price point makes the R1 to great choice, for those who are looking for an IEM with different sound characteristics.


Pros and Cons:

  • + High detail level (above its price level)
  • + Effortless midrange presentation
  • + Great bass response (depending of the filter)
  • + Lots of sound tuning options
  • + Solid build quality
  • + Good accessory package


  • – The stock cable is too stiff and thick,
  • – Possible fitting problems for smaller ears


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3 Responses

  1. Thanks for your excellent review dear Expert Audiophile Moonstar . Congrats for your extraordinary work man 👍👍👍🎧🎼🎶🎶

  2. Beelezbub Soultaker says:

    Good read explained the filters well so I can implement that information with the IMR Rah’s, nice work !

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