IMR Opus Mia review : The expansion king


I have good amount of experience with ES based earphone under $1000 mark. The Mia is unlike most of them. ES drivers are mostly tuned a bit bright and deliver a tinglier and grassy feel to them but the Mia has it polished, for good or bad, is up to the listener.

The Dynamic driver has similarly thumpy feel as the R2 Aten, the mid range has very good amount of energy and the treble region has a lively and detailed sound. The sound signature can be labeled as warm and marginally bright.

In their words:
“The unique driver combination featured in the Opus Mia enables it to deliver true to life sound unlike any other in-ear monitor available on the market. Covering every aspect of the audible sound spectrum (and beyond) the Opus Mia delivers the most delicious sub and mid bass which does not bleed into the mid range.”

Tuning NOZZLES:-

Something unique with all the IMR earphones is the tuning nozzles filters. This time around there is an extra back filter which can turn the earphone open or closed without much problem. The Nozzle Filters have “acoustic effects”, in simpler words the nozzles affect the treble transparency and stage and the nozzles have bass effects. Nozzles come in colors of (highest bass first) Black, blue, gold, red, grey, pink/purple, silver and green. The filter doesn’t come with grey or silver color.  You can always mix match the nozzles with filters for the best possible sound.

In their words:

“The Opus Mia features the unique IMR option of switching between open or closed rear ports to suit your listening environment (Isolated/non isolated) and further enhancing the tuning capabilities when combined with the IMR acoustic tuning nozzles (included).”

I have a few preferred combinations. The first one is the Pink/Purple set, it has the best balance of everything, very good tonality and a slightly laid back sound with plenty of stage. For those who like thumping bass which has plenty of rumble and body should go for the red filter and grey nozzle. It delivers a bit bore notes definition too. The Combo of red nozzle with black filter has similar feel but has a bit more control over the notes.

The back filters are useful if you feel the Mia is leaking some sound or you feel the need to switch to closed back design. Going closed reduces some stage depth and makes the Mia’s stage a bit conical. I do not prefer the closed back setup.

P.S.  I am using the purple set for this review.


IRM has a fairly rare dynamic piezo ceramic driver for the lower end which has reached its 5th generation. At its best it can deliver plenty of thump and rumble but the lower end is totally dependent on the nozzle and filter combination. Bassy set of nozzle and filter are blue, black, gold and red. These filters deliver plenty of bass with excellent thump, letting the dynamic driver express with its full potential. It has very good sub-bass reach but the Fibae 4 and few other earphones do manage to deliver better depth. The mid bass is fuller with excellent body and meaty notes. It has excellent volume and a wholesome feel to it. Decay is on the slower side. It is slightly slower than the Fibae 4 but is a hair faster than the Shozy Pola. The upper bass is a bit more forward than it should be but does not feel uncomfortable. It has the required amount of precipitation which gives it the juicy feel. It rides on very good amount details and texture. The level of texture and resolution is very good but is slightly shy of something very capable in this regard as the Shozy Pola. The upper bass is nicely contained and melts nicely into the lower mids. The dynamic driver has a nice organic feel to it.

If you feel that no, the purple set is not doing it for you, you will like the Blue and black set more, these sets deliver bigger body and moves more air with a bigger slam.


Even though the Mia is much similar to the Pola when it comes to driver configuration the mid range does not take the back seat like the Pola. The transition from upper bass to lower mid region has a bit or extra energy which feels a bit different as most of the IEMs don’t have added emphasis to this region. It gives the lower mids a bit of brightness, coming from a slightly warm and cushiony lower end this takes things to a unique territory, instead of being drowned it emerges like a phoenix. The vocal region levels the extra energy a bit and rest of the mid range is aligned with the rest of the spectrum onward. Both male and female vocals have very good clarity, definition and resolution while maintaining excellent level of texture like the Pola. The tonality is accurate with a slightly organic feel to it. Instruments have good amount of shine to them with good body and the slightly polished finishing eliminates unnecessary sharpness. The upper mid has a slight dip which helps in keeping the notes away from sibilance or harshness.

IMR Mia has a nice balance between being musical and analytical, the notes are not too aggressive, sharp or thin without compromising with bite, it deliver accurate notes thickness and depth. Finishing of the notes is very good. It has a well polished feel to it without leaving any edginess or graininess. The overall level of resolution and details is very good. It does not have the crispiest contrast between foreground and background instruments as it smoothens out a bit of micro details, there is nothing missing but don’t have much bite to them.


The treble region is nicely energized with good amount of spark to it. It sounds crisp and clear. The resolution and level of definition is very good. The instruments don’t sound thin like BA based IEMs. The Mia has nice weight to the notes without being mushy or blunt. It bites but with love, leaving a full bodied impression. Level of details retrieval is very good, it just doesn’t miss out on anything while keeping the timber closer to natural. It doesn’t have the kind of bite or attack like the UM Mirage or Andromeda, keeping notes under the harsh margin. You can just sit back and enjoy the music without bothering about any sharpness or uncomfortable notes while enjoying the delicacies of the track. The organic tonality adds more character to the sound.

It has very good amount of air between instruments. Thanks to its slightly bright nature it resolves exceptional cleanliness compared to the darker sounding Fibae 4. The Treble extension is as good as anything else in this price bracket. It maintains fantastic amount of energy deep into the spectrum. The Huge stage size helps a lot with instrument placements and density. Layering and separation is fantastic with precise instrument placement.



Suman Sourav Meher

Suman Sourav Meher

My humble audiophile journey started in 2010, when I was in college, where I fell in love with the elements, nuances, and variations of this mesmerizing world. The ability of tiny earphones to recreate amazing sounds made my bad days tolerable and good days better! Now I am a full-time audiophile with a preference for musical tracks, especially vocals and engaging ones. I must admit I am addicted, but not to drugs or alcohol, but to earphones. Come join me as I share my experiences, bad or good, and let’s have some fun!


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