Unique Melody MEST Mk I vs Mk II comparison – improving on perfection


I purchased the MEST Mk 2 from Andrew and MusicTeck USA at full retail price, with the intention of reviewing them. No input has been sought or received from MusicTeck or Unique Melody with regards to the content of this review – the opinions expressed below (however ill informed) are 100% my own. Many thanks to Andrew and his team for getting the MEST from New Jersey to the wilds of rural Bristol in the UK in less time than the local post takes to a deliver a parcel from 15 miles away!

To read my full review of the original MEST, please click here .

A full review of the new MEST Mk 2 will follow in the next week or so.

Background on the MEST series

In the modern audio landscape, it often seems that progress waits for no man (or woman), with new models and technological innovations hitting the shelves almost weekly. This certainly holds true for the Chinese IEM giant Unique Melody – my last published review on this site was an assessment of the MEST Mk 1 (see link above), and less than 12 days after my lovingly crafted word salad hit the digital press, I’m sitting here typing out a piece on the upgraded Mk 2 model. It’s safe to say that the MEST was one of the hot ticket audiophile in-ears of 2020, so it’s more than a little surprising to see Unique Melody hit the upgrade trail already.

Reading around the story behind the new version, it would appear that the UM guys and girls have been reading every single review of the original model, making a series of small but important tweaks to the design, accessories and sound to address pretty much all of the non-positive comments made in the slew of reviews this IEM has received since launch (of which there really weren’t that many to begin with). The tuning has been “adjusted” for a more Western target market, with slicker ergonomics in the shell and cable designs and a much more premium experience with accessories and general cosmetic appeal. The driver design remains largely the same, with improved airflow around the 10mm dynamic driver being used for the low end and a new “B2” bone conduction driver, which operates across a much wider frequency range than the original.

Initial impressions on sound

Even though this is a comparison review, it probably helps to write just a little about the general sound signature of the MEST Mk2, for those who haven’t already had the pleasure of the original.

In general terms, the Mk2 offers a “W” shaped tonality. If you aren’t familiar with the various audiophile letters that get used to define the sound of headphones or earphones, this basically means that the bass, mids and treble are all roughly in line with each other, with no particular section deviating too far from the others in terms of overall presence or quantity. So, why not just call them “neutral”? The W in the shape indicates that these aren’t just ruler flat, and there is some careful sculpting of the signature as you rise up from bottom to top to emphasise (or de-emphasise) certain aspects. So, these are balanced, but definitely not pure reference, with some very careful curation of the overall tuning to present a sound that is musically engaging, rather than dry or sterile.

With regards to the bass, this is a little north of neutral in quantity, but I wouldn’t call it a bass head level of volume. There is plenty of oomph in the drivers where needed, with a decent balance between sub-bass and mid-bass to provide a nice sense of physicality to proceedings, as well as a little slam. Texture and detail is top notch, with the MEST Mk2 driver being able to produce tight, detailed bass with plenty of body but without a lot of flab or reverb. It kicks when it needs to, but keeps a tight grip on proceedings while doing so, coming across as somewhere between textured and ever so slightly dry to my ears.

The bass tapers down into the midrange, picking back up again as it pushes both male and female vocals forward on the stage. This is middle “spike” of the W shape, and helps the MEST provide a sense of scale. The midrange is mildly warm, with enough substance to provide a nice sense of thickness to both vocals and stringed instruments. Detail levels are very high, with plenty of separation around the various elements of a track that allows the MEST to avoid sounding congested or stuffy. The mids are tuned more towards the emotive end of the spectrum rather than classically neutral or flat, borrowing a little from the old Final Audio “rawness” in the presentation that captures the emotional weight of a singer’s voice.

Treble is again similar in quantity (possibly slightly more forward in both volume and stage position), with the now-classic Sonion EST style of presentation which is smooth and weighty but still highly resolving. This is backed by both the BA and BC drivers as well, and can be considered a highlight of the Mk 2. It isn’t the most open or sparkly presentation you will ever hear, but detail levels are again at flagship-tier, and the sheer effortlessness of the presentation helps the MEST cut through the hottest of tracks without so much as a flinch.

Staging is on the grand side, with a truly three dimensional sense of space that sometimes seems to wrap around behind the head of the listener, expanding outwards in all directions and allowing plenty of space for each instrument or vocal to inhabit their own distinct audio space. It isn’t the widest or deepest IEM I’ve ever heard, but I haven’t heard anything yet that can compete in all three directions.

Separation and layering are also flagship-worthy, with the MEST Mk2 being able to keep each different strand of music neat and distinct, and placing everything with pinpoint accuracy in the expanded 3D soundscape. This really is a treat if you are into IEMs that present a clear sonic image, and the addition of a small sense of added “reality” to the sound that accompanies the use of the bone conduction drivers is definitely helpful here.

Comparison between Mk I and Mk II – build

To best describe the relationship between the MEST Mk1 and the new revision, the phrases “prototype” and “finished article” spring to mind. The Mk1 wasn’t a poorly built or sub-standard IEM by any means (nothing I’ve seen from Unique Melody is ever any less than good in that respect). The Mk2 is simply an improvement in pretty much all the areas that matters, with each aspect of the MEST receiving some attention to address issues or comments that have been made by both end-users and reviewers over the last year.

Starting with the design, the Mk2 sport a new, smaller shape. The overall size of the IEM has been reduced significantly, with slight tweaks to the inner face of the shell and the angle of the nozzle to move more towards the now common “pseudo-custom” shell design compared to the straighter and more angular design of the original. For me, this allows an easier “deep fit” of the IEMs, which is crucial in getting as much of the IEM shell into contact with the surface of the ear, so that the bone conduction voodoo can take place. The Mk2 stick out less, and fit more snugly in the ear for extended wear. To be honest, I never had any issues with the long term comfort of the Mk1 variant, but the more compact and better fitting design on the Mk2 model definitely seems like a step up here.

Cosmetically, the Mk2 is a step up as well. UM have moved to a full carbon fibre shell rather than just the faceplates on the original, and the addition of small flecks of gold into the interwoven black carbon fibre design is a classy touch. The finish on the shells is similar in quality between the two models, but the other cosmetic “bump” comes with the venting port for the dynamic driver, with UM choosing to seal that with a metal o-ring this time around rather than just leaving a small hole in the faceplate. It looks cleaner and more eye-catching as a result, adding to the high-end look and feel of the revised model.

Comparison between Mk I and Mk II – accessories and unboxing

This is another area where the Mk2 takes a significant step forward. From the look and feel of the box to the included accessories, the Mk2 definitely takes a giant step towards the sort of experience you associate with a high-end piece of audio gear. Starting with the box, it is now a sleeker “jewellery box” type affair, reminiscent of some of the Austell & Kern collaboration pieces with its removable drawers and black lining.

The IEM case is the same high quality Dignis affair, but the included load-out of tips and cable is a definite step forward in perceived quality. The Comply foam tips are still in evidence along with some UM silicone tips, but these are now accompanied by a set of Xelastec tips, made from sort of sticky translucent rubber. This is significant as apart from costing the best part of $30 for a pack (yes, $30), they are the after-market tips that are most commonly suggested on various internet forums for pairing with the original MEST. It definitely feels like someone at UM has been paying close attention to the internet suggestions from happy end-users here, and their inclusion definitely takes the usability of the package up a notch straight out of the box.

The included cable is also a bump up, moving from a UM own-brand cable with quite frankly… er, rustic finishing at the y-split and connection ends to a sleek black rubberised affair from the well-known HK cable manufacturing house PW Audio. The cable is a bespoke design for Unique Melody, with a branded metal y-split in anodised black and beautiful and study looking connectors at both ends, again branded with the UM logo. The whole feel and for of the cable is a giant leap forward from the original model, and its lower-profile black on black aesthetic plays very nicely against the newer black and gold shell design. Another significant change for the Western market is the move away from UM’s traditional QDC/UM style extruded 2-pin connector, where the cable end effectively has a small sheath that slips over the extruded 2-pin socket on the IEM shell. The new MEST switches that out for a more traditional CIEM-style 0.78mm 2-pin socket, which is flush with the shell of the IEM. This may lack a little protection against bending the pins compared to the previous design, but it does open up cable rolling options for a larger variety of popular cables in the more Western markets where the UM/QDC sockets are less prevalent.

The rest of the accessories are the same as the original, but with the improved IEM design and the more visually appealing and high-quality feeling accompanying gear, it definitely feels like UM have more than justified the additional price bump over the Mk1 model here, bringing the whole experience more into line with what you would expect for a $1500 IEM.

Comparison between Mk I and Mk II – sound

The two IEMs are actually pretty similar in presentation, with the original MEST sounding almost identical to the new, “improved” version. There are some small and subtle differences, but for anyone looking for a radical departure from the original MEST tuning, you won’t find what you are looking for here. What you get is more of what made the MEST so unique in the first place, with little tweaks to bring some additional refinement to the party.

Please note that these comparisons are based on my existing Mk1 MEST (into the hundreds of hours on the drivers) and my Mk2 pair with less than 35 hours of actual listening and a similar amount of burn-in on the clock at time of writing. I’m neither pro or anti when it comes to burn in, but if you want a more accurate assessment of where the Mk2 sits then you will have to read that in the upcoming full review, once I have a few more days both in my ears and on the drivers. All impressions given here are made using the Ibasso DX300 in low gain (volume matched), using the 4.4mm stock cable that came with each IEM and identical pairs of RHA TWS silicone tips (as I don’t have another pair of Xelastec to hand).


In the bass, both the Mk1 and Mk2 produce a nice, full sounding bass – the emphasis is weighted to the lower end of the scale on both, and provides a sound that is full but not overbearing or bass head in nature. At a push, I would say that the Mk2 carries just a shade more texture, with the notes sounding slightly more detailed and controlled. It really is a very fine difference – firing up “Palladio” by Escala, the opening cello sounds a hint more raw and gravelly on the Mk2, feeling weighty but still allowing the subtle click in the lower left corner of the stage to come through clearly at the 20 second mark.

Similarly on “Hello, It’s Me” by Sister Hazel sounds just a hint fuller and more textural on the Mk2 in the low end, the slinky bass line packing in plenty of powdery resolution to the bass notes, feeling ever so slightly cleaner in the delivery compared to the Mk1. There really isn’t much to split the two models here, so please don’t expect this to be something that is immediately noticeable on first listen – we are talking ultra-fine margins for improvement here.

“Bad Rain” by Slash rounds off the quick bass test, and tells a similar tale, with the Mk2 papering a little more fine grain on to the outside of each bass note. It’s subtle, but again that word texture springs to mind. The Mk2 bass loses none of the weight from the original tuning, but manages to supplement it with slightly more in the way of fine control, which is quite some achievement given the high bar set by the original model.

Sub bass extension is identical, with both IEMs being able to easily drop down to the low reaches of tracks like “Disc Wars” by Daft Punk without breaking a sweat. Quantity and general tuning is also a tie, with both models shooting for the same sub-weighted style of bass tuning that is becoming increasingly popular in the mid and top tier IEM market. The only differences I can hear are definitely refinement rather than revolution.


The midrange is the one area where the difference between the two IEMs is more readily audible (if slim), with the Mk2. The newer model carries a touch more weight to notes in the midrange, giving vocals a little more roundness and heft without losing any of the clarity. Something like “Song For Adam” from Gregg Allman’s final album sound a little chestier, capturing the phlegm-inflected intonations of the track with a bit more substance than the original model.

This is actually somewhere where preference will play a part – for those who found the original MEST to have a slightly thin or less voluminous delivery around the middle, the extra meat on the bones will be the final piece in the jigsaw. For those who love a (comparatively) leaner, airier sound in the mids, the Mk 1 might well provide that a little better. The slight bump in note weight robs the stage of a little air and separation on the revised version – the Mk2 is still top tier when it comes to separation, but it doesn’t quite give the same sense of distance between each note that the leaner Mk1 tuning manages, trading it for a bigger note size and a better feel of “weight’.

Listening to “The Cold Wind” by Greta Van Fleet, the 70s guitar tone feels just a little less thick and chunky on the Mk1, with the acoustic guitar strumming that kicks in around the 2:25 mark feeling lighter and surrounded by a little more space. The Mk2 adds a little weight and emotion to the rendition, still managing to keep the instruments easily identifiable and positioned in their own zone on the stage, but not quite as far apart as the original model.

“Uber Station” by Rock Candy Funk Party is another good example track to discern the difference between the two IEMs. The Mk2 has a slight warmth to the intro guitar that adds just a shade more weight to the sound. As is the theme developing here, the difference is slight but notable, planting the tune slightly more solidly in the ear than the Mk1.

Firing up some Shawn Mullins for my final comparison track, “And On A Rainy Night” from his recent Revival version of the Soul’s Core album is up for scrutiny. Mullins’ vocal on this track is part-drawl, part subterranean hum, and both MEST models pack it full of texture, but the Mk1 feels more lean and raw in the delivery. Mullins’ raspy tones are beefier and more fleshed out on the MK2, and if anything even more textured. The Mk1 evokes more of an old-school Final Audio tuning style on this track, feeling slightly more raw, where the Mk2 shoots for the thicker sort of emotional resonance that the Solaris 2020 is a master of from Campfire Audio. It’s the biggest difference between the two models, but we are still talking small margins and find adjustments rather than a completely different take on the sound.


The treble is the area where I am able to discern the least difference between the old and new variants. The first-gen bone conduction driver had decent output in the higher registers anyway, so the newer BC setup doesn’t seem to have any notable effect here over and above what was already in the mix. Both variants have a classic EST style reproduction, clean and solid treble sounding pretty effortless as it churns out gobs of detail.

The only real difference for me is in the overall balance between midrange and highs, with the thicker and fuller mids underneath having the effect of pulling back some of the treble height, still keeping the overall W-shaped tuning from the original, but just raising the height of the middle point so it sits far closer in line with the bass and treble in terms of quantity. In other words, the treble is just as good as the original, but seems a little less forward due to the increased heft underneath it.

Comparison between Mk I and Mk II – technicalities

As you will have gleaned from the above, the technicalities on both IEMs are similarly impressive. Separation and layering are top tier, with the Mk1 sounding more spacious by dint of putting less weight through the middle of the sonic spectrum. The Mk2 has slightly better clarity in the low end, eking slightly more out of the dynamic and bone conduction drivers, but resolution is similar enough not to merit too much discussion in the higher registers.

Staging-wise, the Mk1 actually feels like it has more space between instruments but the stage size is the same on both monitors, expanding out spherically from the centre of your head in all directions. The Mk2 paints a slightly “bigger” sonic picture, with the guitar and vocals especially feeling slightly larger in comparison.

Tonality feels ever so slightly warmer and more realistic on the Mk2, compared to the slightly fresher but lighter sound of the original. Again, this is down more to preference than either being subjectively “better” than the other, but if a natural timbre is a priority, the changes in the Mk2 will probably be more appealing than the more stylised tones of the OG model.

Power requirements and gear synergy

It will not be surprising to note that the Mk1 and Mk2 are practically identical in terms of power requirements and general volume from all sources I tested them with. Given the fact that they have Sonion EST drivers providing some of the high end, both IEMs can definitely make use of any additional current that your source can provide, but apart from that, the only marginal difference in playback volume or experience is due to the slightly different tuning in the midrange rather than any major disparity between the two models.

With regards to synergy, neither is particularly source-picky, but the Mk1 is definitely the less forgiving of the two IEMs to my ears with poorly recorded music or low-quality sources. This is down to its slightly leaner and colder nature (in comparison, not subjectively). The warmer tilt and additional fullness in the middle of the sound on the Mk2 tends to make it the more understanding of the IEM brothers when it comes to playing back music that is less than ideal.

Tuning wise, the additional warmth from the Mk2 means you don’t want to pair it with an uber-warm DAP or desktop system if you can help it, whereas the Mk1 fares better with warmer sources if you want to add body. It’s preference rather than better or worse here.


If you are the sort of person who skips to the end of a book to find out whodunnit, you probably want to know if the Mk2 is a worthy upgrade to the original. In one short answer: yes. In a slightly longer answer: definitely yes. The Mk2 manages to take everything that was good about the first iteration and improve on it, sometimes subtly, sometimes with a more noticeable enhancement. Nothing is earth shatteringly different or “night and day” (to coin a favourite audiophileism), but the sum of each additional tweak definitely leads to a feeling of a definitely improved product.

It is fuller but just as detailed, it fits better and the accessories have gone through the most extreme of TV makeovers to produce something that now looks as good (and expensive) as it sounds. Unless having that original leaner and more spacious midrange is an absolute must, the Mk2 is an easy recommendation from me if you are looking to sample some of the best bang for buck you can currently get in the sub-$2k IEM marketplace. If you own the original version the recommendation is less clear cut; yes, I do think it’s better, but whether it is $400 or so better (when you factor in selling the old version at a discount and buying the newer one) will be a bit more subjective. The original is still one hell of an IEM,but it just isn’t quite as refined (sonically or physically) as the new version. Unique Melody, take a bow – you have well and truly nailed that tricky second album syndrome here. To borrow a phrase from another famous IEM manufacturer: nicely done.

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