Unique Melody Mason Fabled Sound Special Edition


Headphoneus Supremus
Mason Fabled Sound - Freakishly Special
Pros: Incredible vocal presentation
Lifelike, nuanced & textured sound
Realistic stage presence
Neutral tuning without ever sounding flat or dull
Cons: Very, very pricey
Larger shells may not fit all ears
About Me

A few brief words about the lunatic behind the keyboard for this review. I became an “audiophile” a few years ago and started climbing the ladder to insanity pretty quickly. I started with some decent IEMs, a few earbuds, dabbled in headphones and eventually ended up on track to own almost every single flagship ever released. I do not believe I am a “reviewer,” per se, but instead just love trying gear and then writing about it when something really strikes a chord with me. You’ll notice a lot of my reviews I have posted are pretty positive and if I’m being honest, I don’t bother writing reviews on a mediocre product. Maybe that’s a polarizing, or lazy view, but I buy all my own gear and am not constrained to write about something I don’t want to. Liberating, really. That said, I’m also not as good as the real reviewers, so this will probably be more about the feels and the enjoyment factor than a true technical analysis. But hey, I promise to do my best either way. I've had a long journey with Unique Melody IEMs, so on that note...
My Unique Melody Journey

While it may not be super important to bore you with the other Unique Melody IEMs I’ve had, I am amongst the few that have owned: Mason, Mason II, Mason V3, Mason V3+ and now Mason Fabled Sound. You could say I am a Mason fan and you would be right, and the Mason IEM holds a special place in my heart because my son’s name is Mason as well. Does that make me biased? Absolutely and I committed to owning every one of them (although this one tested my price tolerance, but more on that later), so I had to have the Mason Fabled Sound as soon as I saw it. The Mason line, to me, has always stood for natural, engaging sound that never had an over-the-top sound signature. It was always a mature, refined tuning – something that is underrated in today’s bombastic approaches to sound. The Mason line focuses on the music, the nuances, the emotions within, and the Fabled Sound is the best of them yet.

The Fit, Finish, Accessories and Extra Goodies


I promised myself I would try not to immediately go here, but I have to and cannot resist. I own two IEMs in this price segment and both of them sound wonderful, but one comes with an incredible set of accessories and one comes with a cardboard box that belongs in the recycle bin. Now, with that out of the way, you get some really cool and unique stuff with the Mason. First, the IEMs themselves, which are crafted carefully with a stabilized and resin shell that looks quite unique (in fact, no two look alike). The shells are a gorgeous translucent blue with segments of wood that really make the IEM look special. Physically, they are on the large side, but they’re quite comfortable to me and the medium-sized nozzle accepts pretty much any tips I would choose to use (Spiral Dot++ for the win for me). The wood itself is apparently harvested from a Cholla, which is a type of cactus, normally found in the Southwest part of the United States and Mexico. Unique Melody isn’t the first to make these stabilized wood shells (Noble. Makes some incredible Prestige designs as well), but they give you some goodies in the box that show their commitment to outside the box thinking. In fact, you get a piece of the stabilized wood and resin that your very own IEM was crafted out of, which is pretty cool.


Moving along to what else you get, well, let’s talk about the cable. It is made by PW Audio and is called the “Attila” cable. It reminds me of the 1960 cable from PW Audio, which is definitely not a bad thing. Handsome black sheathing, UM-branded (and lovely) hardware and fancy shielding that makes it sound like unicorns singing in the night. I like the trend of newer flagship IEMs coming with top of the line cables and this package takes it to the summit-fi level. For that reason, I didn’t bother with cable rolling (yet) and will update the review if I do. I’m normally overly loud about throwing all stock cables in the trash can, but not here – no way. For better or worse, UM has abandoned the 4-pin “Dual Tone” cable, which allowed you to change between different cable material configurations. For me, this was painful because I owned the $2,100 Effect Audio “Phanes” cable that was an 8-wire beauty that no longer works on the latest flagship, but I think the general audience will greatly appreciate that the UM flagships are now standard 2-pin. The sky is the limit for cable options, but it’s sort of a moot point if you plan to enjoy the high-quality stock cable. Only complaint here is that it’s a little stiff, but I’ve gotten used to it and generally enjoy its sound and build to a high degree.


Included with my unit was a really nice leather case, as well as a monstrous Van Nuys case that can probably hold a DAP and two pairs of IEMs. That may just be for the first few buyers, but either way this is outfitted with some seriously nice gear. You also get a great assortment of tips (Comply, Sedna and UM). While I won’t say this packaging is up the level of something like the VE Erlkonig, it’s a carefully thought out and impressive package that I really enjoyed perusing about.

Mason FS – Fabled Sound or FuSang?

I’m going to put a small blurb on this because by the time I finish writing this review, maybe all 20 units of the first run of Mason Fabled Sound will be all gone. Since I began writing and listening to my Fabulous Sidekick, another version has been released that is called the Mason FuSang. This has identical internals (12 balanced armatures, one bone conduction system) and comes in an acrylic shell and includes a different cable. For all intents and purposes, the sound should be the same on both with minor differences due to the materials and cable. So, I guess what I am getting at, is that hopefully you find this review applicable to both versions and you choose which one suits you best based on price. I went all in YOLO-style when I saw the Fabled Sound hit the MusicTeck website, but would be equally happy with the FuSang.


Test Setup

This part is also boring, but it’s important to know what was used as a testing bed. If it’s a 3.5mm jack out of a mid-range cell phone, I believe results will be different than if a top-tier desktop rig was used. Most of my testing was done on my trusty. Ifi iDSD Pro desktop DAC/amp, utilizing the tube amp setting. This is a very neutral source, even on the tube setting, sort of akin to the Hugo 2. It’s capable of presenting extremely detailed sound and a massive, spacious stage. Additionally, I used my Hiby R8 DAP. For when I. was not at my desk. Source files were played from Tidal HiFi (FLAC or “Masters” aka MQA) and the stock cable was used.

Finally, the Sound

Okay, so here we are. The Mason Freshly Sensational is a very special IEM in the way it produces sound. There are 12 balanced armatures which together cover the whole frequency range, along with a bone conduction system that also covers (and enhances) the full spectrum. The sound signature of the Mason Faithful Star is HiFi neutral/natural to me, meaning there is very little enhancement in any one frequency area. I have not seen a graph of this IEM, but I would guess that it is fairly flat with a faint hint of W-shaped curve. This is a very versatile IEM, yet I think it is best served to music with vocals (more on that later). It covers a wide range of genres and can be an incredible all-rounder, with nuanced and subtle tricks that make music sound sublime. Overall, the sound is absolutely top-of-the-line quality and careful tuning becomes immediately obvious when you place these in your ears. Also worth mentioning, this IEM requires a lot of power. I find that out of all my IEMs, this requires the highest notch on the volume knob.


Let’s go through the range, starting with the bass. The bass is tight, punchy, has a slight bias toward mid-bass where the sub-bass is fairly neutral. The bass on these is miles away (in quantity) from IEMs with a dynamic driver like the Fourte Noir or Noble Sultan, yet they never feel dry or lacking down low in the range. Instead, you get the sense that bass is presented exactly how it is supposed to be presented and accurate to a fault. Sub-bass rumble is neutral as I said, with mid-bass punch being pretty neutral but slightly enhanced. Kick drums, for example, thumb quickly and impactfully, but synthetic rumble from certain sound tracks is on the lighter side. Bass is great overall, but judging it on its own does a disservice to this IEMs overall character. It’s a fine bass, done well in a neutral manner. No complaints, but the rumble will not be knocking your socks off anytime soon.

Mids and Vocals

I joke that I have a difficult time describing mids and always just case for bass and treble, but friends, the mids have arrived! Wow, the female vocals on the Mason Fantastic Singers are simply out of this world and provide a feeling of realism right into your ears. Male vocals do the same, with weight and texture that truly make you feel like you are there at the show. Electric guitar riffs subtly (and sometimes vigorously) tickle your senses and ears with realism that makes you look around the room and wonder. I don’t know if this is the bone conduction system, the masterfully-tuned balanced armatures or both, but these IEMs present the best vocals I have ever heard. The entire mid-range, from lower mids all the way to upper mids, are quite linear but with incredible texture, detail and air. A friend recommended trying “Nightlight” by Illenium to showcase the abilities and seriously, this was an epic experience. Now, I’m not saying the bone conduction system vibrates your ears or anything like that (well maybe it does on a subconscious level), but it absolutely does its job to make things sound just a touch more present and near you. At least, that is my guess on what it is doing and what I am hearing. Anyway, back to the sound, I am incredibly impressed with the mid-range. There is not any feeling of dryness, but the mids are neutral, natural and crystal clear with air and space. They are ever so slightly more forward than the bass, but they are not bathed in warmth or enhanced with any thickness. There’s just so much headroom in here that makes the mids the star of the show, giving absolutely effortless and lifelike sound track after track. The overall technicalities and abilities of the Mason Fascinating Satisfaction with regards to vocals especially has to be heard and experienced; I think it’s pretty much the closest I’m going to get in my lifetime to Dua Lipa whispering sweet nothings in my ear!


The trend these days is estat hardware for the highs, but I am slightly unconvinced of their necessity. I’ve had numerous all-BA IEMs and many estats and I’ll go out on a limb to say the implementation/crossover/tuning is what really matters. So here, we have some beautifully-tuned treble with sparkle and extension that deserves the designation of summit-fi. High hats are incredibly quick and precise, while the highest registers of vocals have a spine-tingling realism and feel. This IEM is not overly-sparkly and I do not see anyone being truly bothered by that sparkle, but it goes up to the highest of highs with an effortless attack that ensues so much air in those frequencies. Again, it’s a nuanced and refined tuning that carefully straddles the line of enhanced sparkle and smoothed treble. It’s perfect (for me, a slight treble-head) and I’m really impressed with what UM have tickled out of “normal” balanced armature drivers. And with the bone conduction system adding texture and feeling to the highs, well, it’s a real high that has to be experienced.

Stage and Separation

Probably the most difficult part of any review for me is describing the dimensions of a stage. Thankfully, I’ve clocked in some serious hours on the Mason Favorite Sauce and am confident enough to say that the stage is a selling point of this IEM. While not as out-of-your-head vast as a competing $6,000 IEM, it’s an adequately spacious, accurate and lifelike perception of stage that still wows on first listen. If I were to describe the dimensions, I would say the width is the star of the show with the height and depth falling in line at a slightly lesser degree. Overall, while listening to live music tracks, it’s very easy to close your eyes and picture the concert as you would experience it, without feeling overly enhanced or out of your head. You’re closer to the musicians than some other IEMs with a massive stage, but everything feels lifelike. Hard to describe really, and I seem to be doing a properly mediocre job of that. Essentially, the Mason Fearless Sound presents music in a way that really makes you feel close to it, rather than testing the distance of just how far that drummer can be off to the left, or that bass guitar off to the right.

Separation on the Mason Fashionably Sassy is above average with impressive depictions of instruments. This IEM is not all about detail, with resolution not being the defining trait. But, it still presents massive amounts of detail, just in an effortless and natural way. Nothing sounds clinical, nothing sounds forced and you won’t find yourself testing whether or not you can hear someone sneeze in the third row. Instead, this is a tuning that takes you past analyzing each sound and lets you enjoy an soundscape that has all the details in the right place. Natural, neutral, very high-resolution and never overdone. It’s impressive and I never tire of listening.


UM Mason V3+
: I loved the V3+ from the day I got it for its natural, smooth sound with sublime layering and texture. It sounded like a big IEM, and needed a lot of power to get the best from it. I’m happy to say that the Mason Follow-up Sound does not stray too far from the V3+, but there are differences worth mentioning. The V3+ has a thicker, warmer tone to it where the latest and greatest goes for ultimate neutrality and realism. V3+ has a big more bass impact, where Fabled Sound goes for speed, clarity and precision. Mid-range is similar tonality-wise, but the Mason Freakin’ Special gives that texture I mentioned earlier where you can feel the singers notes. For vocals, nothing can touch the Mason Fantabulous Singers’ ability to make you feel like you are part of the music. Treble sparkle is enhanced and more extended to my ears on the Fabled Sound, but that may be the smooth tuning of the V3+. Detail-wise, I think I hear a bit more clarity in the latest version of Mason, though V3+ is obviously no slouch. Stage is comparable on the two of them, but perception of being in a live concert goes to Mason Full Stadium due to its magic and unicorn dust in the mids, courtesy of the bone conduction system.


EE Odin: this is an interesting comparison because these monitors are miles apart in technology and sound, yet they’re both going for super high-fidelity neutral tuning to give you ever last ounce of your music with nothing lost. I should note that I’m using the wonderful Effect Audio Code51 cable with the Odin, which adds a touch more resolution and transparency in comparison to the stock PW Audio 1960. With that said, let’s start with the bass: Odin wins here. Whether you’re a bass head, neutral head, whatever head, the bass is just better on the Odin. It hits harder, rumbles deeper and has an incredible sense of texture. The rest, I’m afraid, I think would go to the Mason Frequency Star. Into the mids, the Mason has texture, realism, warmth and timbre that the Odin does not compete with. Odin is a very neutral, dry mid-range that may have a touch more detail, but the Mason really presents mids and vocals in a more effortless way that is less fatiguing and more enjoyable to my ears. Treble is where these two IEMs also differ, with Odin being more precise and sharper while Mason has a denser and more relaxed upper end. It’s hard to tell which has higher extension and I would probably call it a tie, but Odin has been reported to bother treble-sensitive listeners (but I love it and crave that precision). Stage dimensions sound roughly similar to me, where it’s a little hard to judge or declare a winner because of the different tuning nature. Mason Feels Soft in comparison to Odin, where Odin is sometimes too much for a relaxing listen.


Noble Sultan LE: the Sultan LE has been my favorite all-rounder hybrid because of its fun bass with a W-shaped signature. In this test, I paired the Sultan LE with the awesome Eletech Iliad, which takes all of the Sultan’s characteristics and turns them up to 11. The Sultan never does anything wrong, it’s just pure fun with dynamics in spades and an engaging but non-fatiguing listen. The Mason Familiar Secret is a more nuanced, more mature sound that has a lighter touch on everything. That’s not to say there is less body in the Mason Fully Satisfied, but the Sultan is the energetic party animal where Mason is more reserved. Resolution and detail, despite having wildly different tuning, seems to be on-par. Bass on the Sultan LE goes deeper and hits massively harder, where Mason is tighter and quicker as to be expected. Mids, again with Mason Freakishly Special, have a physical touch that no other monitor I’ve heard can compete with. But Sultan is still excellent here and the W-shaped signature really works well for it. The mids and vocals, despite bombastic bass and sparkly treble, are always present thanks to the Wizard’s clever tuning. Into the higher notes, I hear Sultan having a thicker, denser treble (as is consistent with most estats I’ve heard, sans Odin). The Sultan is the more fun of the two, where Mason’s Final Solution is that it gives the best interpretation of vocals/singers that I’ve heard to date.


64 Audio Tia Fourte Noir: of course the Noir has to be included in this comparison, given its musicality, technical prowess, somewhat-cult following and unique sound. That said, these IEMs give the listener quite different experiences and sound signatures, so I’ll declare right now that it’s again hard to pick a “winner” and will depend on what the listener prefers for themselves. Starting with the bass, the Noir has a warm, thick, analogue-sounding dynamic driver kick that is one of the best I’ve heard. Still no Legend X in quantity, but it’s definitely north of neutral. It’s on the slower side, where the quicker attack of the Mason Faster Slam is immediately obvious. Quantity-wise, the Noir has much more bass, both in the sub and mid-bass regions. Into the mids (and acknowledging that the Noir is an improvement over the original Fourte here), the Mason Fancy Specimen has a more lifelike feel and has a greater ability to connect the listener to the vocals. Noir has a nicely textured and warm mid-range, but the Mason vocals shine through clearer and with more air. Into the treble, Noir is hard to compete with given its Tia driver and very high extension. These two are fairly close, with perhaps a very slight edge going to Noir in extension. Mason Frequency Spectrum comes close, with plenty of sparkle and extension and sounding the more natural of the two. Performance is fairly close here and I find myself struggling a bit to find any other differences in the highs, which is a great thing for Mason. Detail and separation is similar on the two, though Noir sounds a little less natural and Mason sounding more effortless in its detail portrayal. It’s hard to believe that just a bit ago, Noir was on the very extreme end of IEM pricing – but Mason Financial Sadness has changed that right quick! Oh and I almost forgot to mention, Noir was paired with a beautiful pure silver cable lovingly crafted by Justin (@doctorjuggles) at Khanyayo Cables.


Oriolus Traillii: I could probably spend a few days just listening to these back to back and I do actually question my own ability to fully report on the differences between these two summit-fi IEMs. But what the hell, let’s give it a go. I promise not to talk about Traillii’s cardboard box anymore as well. The first thing that struck me upon listening to Traillii was an insanely wide stage that extends fully out of your head and into your neighbor’s yard. It’s almost uncanny and is very special in that regard. Once you get over that jaw-dropping stage, you hear an incredibly deep, impactful bass that would make you wonder if there actually is a dynamic driver contained within. Switching over to Mason Feeling Second-best, there are plenty of tricks up its sleeve to not only compete with Traillii, but surpass it in some areas. Stage, while not as insanely wide or deep, gives the sense of being inside the music and actually at the live show thanks to the physicality and texture (likely from the bone conduction system). Dimensions are narrower, but you get a similar grin-inducing feel and immediately know the IEM is special in its own right. Bass is quicker, though less impactful than Traillii and doesn’t extend as deep. Into the mids, the Traillii is very good in its own right with a very clear, natural and airy presentation of vocals. Mason Formally Surpasses in the area of vocals for me, though, with a more bodied sound in the singers’ voices and that texture that I’ve talked so much about (Dua Lipa...whispering...you know...). Traillii is quite balanced, though somehow Mason almost makes the Traillii sound a touch U-shaped given how present the vocals are on the Mason. Into the treble region, damn, this is a tough one. Traillii extends way up into the maximum registers with an effortless air and sparkle that is some of the nicest treble I’ve ever heard. Mason Fresh Shine has incredible sparkle and extension too, but it’s not as effortless and natural as Traillii. Notes up high are a touch thicker, where Traillii is so light on its feet here. Neither will bother treble sensitive listeners in my opinion, because they don’t sound bright at all. It’s treble done perfectly in my book, with Traillii being the airier and sparklier of the two, with a touch more thickness on the Mason. For detail and separation, I really cannot choose a winner here given the different way these IEMs portray the sound. What I will say is this: putting either in your ear gives you the summit-fi experience and both perform so exceptionally well. Traillii might be a “safer” bet because it does nothing wrong, but Mason Fascinating Solution really brings home a special texture and sound. Both come with top of the line cables and both will give you endgame performance several times over. One comes with a cardboard box. Sorry.


Here we are at the end of the review and I’m left with this feeling that I haven’t managed to even scratch the surface of describing what Mason Faithful Soulmate is capable of and I blame my own lack of creativity and writing for that. But at the end of the day, I think it should speak volumes that I spent $6,000 on an IEM and I am pleased with it. And yet, that is the elephant in the room: should anyone actually be crazy enough to spend that on an IEM? Well, let me tell you my justification and you can take it with a grain of salt: I know myself too well, and I know that I will never be happy until I own the best. It’s sick, really, but I am chasing that last ounce of performance and fully acknowledge that it comes at great financial cost.

This IEM brings a lot to the table other than just great detail, stunning looks and top of the line accessories. It brings a realism to vocals that I have not heard on anything else, it brings an immersive experience that has to be heard to be believed. While it does most things exceptionally well, it does vocals the best I’ve heard and some might say that in itself is worth the price of entry. Others may say there is nothing on earth that this IEM can do that would be worth that price of entry, and that’s fine too. At the end of the day, this IEM is absolutely a keeper among my stable of gear and it will be with me for a long time (I hope). Whether you go with the Fabled Sound or the FuSang, you’ll get a unique IEM that exudes quality and engineering, with love and soul installed by Unique Melody. In this segment of the market, Mason Firmly Sits at or near the top depending on your preference.

Huge, huge thanks to Andrew at @MusicTeck for allowing me to reserve serial number 001 of this. I will keep it forever and give it to my son Mason when he is old enough to appreciate it. He will probably wonder why the hell there are thick black wires coming out of it and won’t have a device to plug it into, but those are problems for tomorrow.



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King of “FS” acronym word-plays, well done👏
Really wonderful review. Thoroughly enjoyed reading it. I can’t wait to receive mine:) and I loved all the word plays on the FS acronym! So good!!
amazing review, C, tks.

the final mention of the cardboard box got me good 😂

looking forward to hearing this for myself in a couple of days...


500+ Head-Fier
A Wonderful Work of Art
A Wonderful Work of Art—Unique Melody Mason Fabled Sound(FS) Review


Unique Melody is running crazy lately. With the releases of MEST, MEST MKII, 3DT, and now Mason Fabled Sound (and the Fusang). It is undoubtedly one of the most heated IEMs brands now. The application of bone conduction drivers (BCD) is definitely attention-grabbing to us audiophiles and successfully brought this veteran IEMs manufacturer back to life. Based on my experience, Mason FS is a clear step-up of MEST and MKII regarding the utilization of BCD. It is truly something unique, and nothing sounds like it so far. The $6000 price tag is not that approachable to all of us, just like when Traillii was launched. But when considering the exclusiveness and the premium quality, it might worth it. In this review, I will talk in detail about how Mason FS feels and sounds.

Disclaimer: This pair was loaned to me by Andrew from MusicTeck who is a dealer based in NJ. He carries an amazing selection of products including IEMs, portable music players, headphones and cables.

Packaging and Accessory
Mason has decent packaging and accessory sets as always. I want to point out that the leather case from Dignis is terrific, and the quality is extremely high class. The Azla Xelastec tips are always my goto tips for all my IEMs, but the stock black/blue silicone tips sometimes provide me a more open sound when pair with Mason. Overall, I would give Mason’s packaging a solid A, not the most luxurious looking like VE’s but very practical.

The “Attila”

Attila is the custom cable that comes with Mason FS. According to the UM, Attila is specially tuned for Mason FS, manufactured by PWAudio. For its exterior and stand-alone price($1999), I initially guessed it was based on the 1960s 4 wires. Unfortunately, I no longer own the 1960s, but I have the stock cable for Traillii, which is based on 1960s 4 wires. Interestingly enough, I found these two cables are quite different.
The Attila is a bit stiffer than the Traillii’s cable. It may be because the Attila is still relatively new or the inner shielding or core materials are indeed different. Sonically, Attila has a better dynamic, and it also makes the bass to mids sounds more bodied and has a better texture. However, the treble from Attila is not as airy as the Traillii’s cable. Oddly, pairing Attila with Traillii creates a great synergy, even better than the Traillii stock combo, mainly in image and dynamic. Not the other way around, Mason FS with Traillii’s cable makes some flat and dull sounds. Both cables are of TOTL quality, but the Attila is closer to my preference, and in my opinion, the Attila has slightly better quality. (Note: Results were concluded from the tests based on both Mason & Traillii).


Mason FS is the true Unique Melody. It is something that I have never heard before in my life from both IEMs and full-size cans’ camps. However, you can still tell it is from the UM, and it is in Mason’s line-up as it shares a similar reference tuning trend as the previous Mason V3 and V3+. UM further enhanced the term “reference” with Mason FS as it delivers an extremely neutral tonality, a photorealistic texture & image, and a perfect spherical soundstage. It outperforms almost all the IEMs I have heard in technical performance, except Traillii in the soundstage size comparison.

Timbre and Tonality
The timbre of Mason is superb, and I am pretty certain it is the most appealing one I have heard. It is mellow but not soft at all. Every note has an exceptionally well-polished edge, and in the meanwhile being very rich and solid. Nothing harsh or brassy. It also sits in the perfect neutral place between bright and dark. I am completely falling in love with FS’s timbre, and it is the absolute king in the realm of timbre and texture. Surprisingly, I found most of the other TOTL IEMs are pretty far away from the throne, with only a few exceptions like Erlkonig, which is close but still not there.
In terms of tonality, I found FS is on the neutral-warm side. It has some lovely sweet and warm tones but without fuzziness. It mixes the attractive warmth and world-class resolution perfectly. FS also has a slight emphasis on mid-bass, making the overall sound super authoritative and powerful.

As I mentioned above, FS has a slightly emphasized mid-bass. The sub-bass is awesome too, but just not as prominent as the mid-bass. Therefore, the overall bass performance is on the clean, fast, and hard-hitting side, not the warm, rumbly bass. Meanwhile, I found the bass notes from FS are always in precise figures and retain a beautiful physicality throughout the lower frequency. It punches really hard, and I can almost air is squeezed out of the bass drum and hit right in my face.

The signature of FS’s bass is quite versatile. I found it suits perfectly with many genres, and it really shines out with some rock and metal tracks. As I was testing the In Waves from Trivium, FS keeps delivering the fast, clean and punchy drum lines that are heavenly satisfying. Similarly, with funk and instrumental jazz or fusion, FS’s tight and punchy bass makes the tracks sound clean and fluid. For classics, I think it is down to your preference. If you prefer some tight and precise bass, I think FS is spot on, and it is undoubtedly one of the best, if not the best. However, if you are looking for some rich sub-bass and craving bass rumbles, there are some better choices like Thummim.

As much as I wish to hold myself and write an objective review, I can’t while writing this part.
Like lots of the users have declared in the forum. Mason is the Mid King. However, I don’t think UM engineers have added extra spices to the mids, but they amazingly utilized the bone conduction system on the Mason FS. To me, it is again the uncannily beautiful texture and timbre that play a critical role here. The mids and vocals from FS are not upfront or sit backward. They are again at the almost perfect “reference” position, which sounds very natural to me. Now, here is the magic, the mids and vocals from Mason are incredibly life-like. As mids are the most familiar ranges to most of us, you will be more likely to have an “emotional echo” with FS’s mids. I have tested so many vocals from both females and males. I also tried lots of mids-centric acoustic guitar and piano tracks, all of them sound insanely well. There are no artificial flavors added to this beautiful mids, but the natural, pure sounds constantly hold my breath.

If I have to pick my least favorite parts from Mason FS, it would be the treble. However, by no means, Mason’s treble is bad. To my ears, the treble from Mason is silky smooth with nothing harsh or raspy. Meanwhile, the treble extends very high and creates some decent air. I can feel that UM is trying to tune the treble of Mason to be “flawless”, but to me, the biggest flaw of Mason's treble is being “flawless”. I always wanted some sparkles or even some edges to add excitement to the music, but that cannot be found from Mason without EQ. It is not very noticeable of lacking excitement while playing vocals or classics, but it is pretty apparent for cymbals heavy tracks such as Metal.

Soundstage and Image
The soundstage of Mason FS is perfectly spherical. You can quickly get a holographic “vision” once you plug them in. With the bone conduction system, you will also get an immersive feel which you can rarely find in a personal audio system, IEMs, headphones, 2.1 speakers, all included. MEST MKII has already given me that sense, but Mason FS is providing me the grown-up feelings. Mason FS will lead you to the stage where the instruments and singers are surrounding you. You can have the sounds from the top/ bottom, left/ right, front/back, and you are coated by the music.
The images are one of the most accurate and natural images that I have got from the IEMs. The images are not too far nor too close, and meanwhile, it has completely no compromise in size and thickness. All notes retain exact precise figures from bass to treble. Combined with the soundstage signature, Mason FS creates the most photorealistic images I have ever heard. However, due to the excellent thickness and fullness in imaging, Mason FS is not the most spacious and open-sounding IEMs. Mason FS perfectly mingles the involving and resolving natures of the high-end audio gears.

For all the IEMs I have heard, the bird Traillii is the only one that comes close to Mason FS and worth comparing. And it is quite interesting comparing “ The Wood” versus “ The Bird”.

Design & Fit
Mason FS offers prestige stabilized Cholla shells coated by blue resin that look absolutely stunning and unique. The shells are slightly on the larger side especially come to the nozzles. Fortunately, they are not making any trouble to my medium size ears. As a reference, VE Erlkonig is the largest shape I can bear, and FS is more ergonomic than VE and fits me better.
Traillii offers custom faceplates. The default shell design is classic but not outstanding. The design is outperformed by Mason in the side-by-side comparison. The build quality is very close to Mason, but I would still give the edge to the Wood. However, the fitting is better on Traillii, the Bird has thinner nozzles, and I think it is slightly lighter than Mason.

Packaging and Accessories
Hands down, Mason is the clear winner. Compared to the closefisted Oriolus, UM offers way better packaging and a lot more accessories. Mason comes with a more excellent hard case than the generic 50 cents parper case that comes with Traillii. Mason also has one of the most premium leather carrying cases from Dignis that is aesthetically beautiful and practically durable. Meanwhile, Mason comes with 3 sets of tips: Azla Xelastec tips (S/MS/M), Comply foam tips, and the house custom black silicone tips. All three tips are excellent in quality. Oh, also, the small magnetic shirt clip is a lot more useful than you would expect. Plus, Musicteck is offering a similar and better/larger (than Traillii’s) VN case as a bonus.

Both Mason and Traillii are easy to drive. I found Traillii is less picky about the source and slightly easier to drive. Mason is not hard to drive, but it is very fastidious about the source.
Due to the fact that Mason is having a reference and slightly flat sound signature, the less dynamic/gentle tuned AK devices are not ideal with FS. Things like R2R DAPs and tube amps are giving some nice flavors to the Mason. DAP like R8 that provides an excellent dynamic and a decent EQ system is not bad for Mason as well. With better DAC and AMPs, Mason FS can noticeably stack up. On my desktop setup (Bricasti M1SE + Cayin HA300), Mason sounds speechlessly amazing despite there is a noise floor from the 8W tube amp, lol.

Traillii, on the other hand, is more source-friendly. It will have great synergies with the major high-end DAPs that are currently in the market. The only thing you might need to care about when selecting the source for Traillii is the “control” in sound. With some external amps, the Traillii can sound shouty and less natural. But still, I found Traillii is a lot easier to the sources.


Having both Mason and Traillii is just the end of the game, no more searching and no more wrangling. Both of them are amazing, but they are very different and almost antipodal in tuning ideology.
In the overall signature, Mason focuses more on texture and tactility. It has wonderful microdynamics that can send the tiniest vibration changes to your ears. It sounds incredibly natural and realistic but unique too. Overall, it is more artistic and authoritative than Traillii in terms of tuning.

Traillii, on the other hand, sounds more open and buzzy. It is emotional and always energetic. It is the most open-sounding IEMs I have listened to so far. The soundstage is simply excellent from Traillii. It has the most expansive stage from and IEMs, and you can hear all the details are flying around you. So, in my opinion, Traillii has a more attention-grabbing tuning than Mason.

In the bass, Mason has the emphasis on mid-bass. It is fast, clean and punchy. Traillii has more sub-bass rumbles and sounds more linear. In mids, Mason has the unique tactility which nothing can come even close. Traillii’s mid is not bad, but compare to Mason, it is generic, and I won’t be surprised that you can find a similar or even better mids than Traillii’s at a lower price range. But you can never find the mid-frequency from any other IEMs that are similar to Mason, period. Traillii’s treble shines out! It is sparkling, airy, and full of energy. It always catches my attention while listening to them. Mason’s treble is slightly darker than Traillii, a little less sparkling, and less energetic. But Mason’s treble is even smoother and more natural than Traillii. It is the smoothest treble and sounds very mature and well polished.

So, in conclusion, Traillii is the King of Mainstream IEMs. You might hear many IEMs similar to Traillii, but no one is tuned as well as Traillii in that genre. Mason is the leader of a revolution, and it truly opened up a new feel of the sound. It brought the sound with one extra dimension. Nothing comes close to Mason in terms of sound signature, and it is still tuned beautifully with all the high-end performance you are expecting.

Final Verdict
Mason is crazy. I still find myself wordless in describing how it sounds. Mason FS is for sure the groundbreaker to the industry with the fantastic utilization of bone conduction drivers. It added tactility to the sound, which has never been done before. Even the in-house MEST MKII is not close in terms of the “bone conduction effect”. As a $6000 MSRP IEMs, by no means I should say it is a bargain. But for the uniqueness, exclusiveness, and awesomeness of Mason FS in sound and design, I think it is definitely worth the price tag. Ultimately, you are getting the finest made audio gear with an exclusive sound signature and technical performance that can never be found elsewhere.
I would be interested in hearing how these compare to the EE Odin.
Wow, they certainly look amazing! I wish I could try them
I wonder how the Mason FS compares to full-size headphones at the similar price range:L3000: