1DD/4BA/4EST/1dBC Quadbrid

This is my first Unique Melody product as well as my first experience with bone conduction tech so this will be a journey for me in finally seeing (hearing?) what all the fuss has been about. I will do my best to structure this post so its easier to digest as this will be the first time I’m moving to the article based layout for my impressions which btw is just that, impressions. This is not a review I’m not a reviewer nor want to be considered one, so take everything I say at face value and in careful consideration.

I primarily listen to Japanese music, and female vocalists dominate the majority of the content I consume with some exceptions. I like a lot of different genres ranging from pop and rock, to ambient and jazz and orchestral, but most of the stuff I listen to is more modern so keep that in mind.

I’ve had the Mest Indigo in house for a little over a week and I have probably close to 50 hours of actual listening time. This is a loaner kit and has crossed a few other people’s hands before mine so it was adequately burned in before reaching me. I have done all of my listening through local playback with either redbook or hi-res files on my L&P P6pro natively or through usb audio input to my main pc using roon as the interface. The stock cable is what I have used the most (more on this later).

The indigo fits me like a glove and is very ergonomic, not very heavy or bulky either. It’s light weight is likely due to the carbon fiber shell. I can get a fairly deep fit which is very good since the bone conduction works better the more contact the shell has with your ear, I’ve heard this is a problem with the earlier iterations of the mest where people would have to go custom to take full advantage of the BCD (bone conduction driver). I’m using Azla Sedna earfit light tips as they have the most secure fit for me while doing a great job of keeping the signature balanced and not tilting it one way or the other.


The indigo is quite honestly a stunning iem; for my preferences it was a love at first listen experience. For me that doesn’t happen very often, I can only think of one headphone (susvara) and one iem (traillii) that has been the case and they are both prohibitively more expensive so the Indigo is doing very well in that regard.

The overall sound is balanced with a W shaped tuning with close to TOTL levels of clarity and has a more laid back signature with some good body and warmth, that’s not to say it doesn’t have oomph but it is no way a intense or overly forward sound.

The bass is so pleasing, especially after my last few sets being balanced armature based (which I love for different reasons), I now am starting to realize that I need a DD set for the times I want that more visceral textured low end which these provide in a very tasteful, not overpowering way. Sub bass has that nice rumble and added texture that tickles your eardrums at times and the mid bass is nicely pronounced and punchy with slight slam with some pretty good dynamics. I would say that these are very adequate for my needs in quantity when it comes to bass but they are not cannons and won’t bump as hard as some others.

The mids are mostly in line with the rest of the frequencies and is not overly forward nor recessed, vocals sit front and center of your face and sound very clear and present in the mix with a slight forward tilt in the upper mids. Both male and female vocals sound very natural in tonality without being shouty. As someone who loves mids this is very acceptable and does not leave me wanting much more.

Treble is smooth and not peaky or sibilant at all but could use a bit more sparkle for my preferences, but nothing to complain about and it does an excellent job. I’ve read that the Indigo has noticeably less energy up top in comparison to the Mest MKII which tames a lot of the sibilance and treble hotness that some people took offense of with that set. If the trade off for those gains was a little less air and sparkle I think it is a worthwhile compromise and seemingly lends itself to the indigo’s smoother and natural tonality treble in comparison.

Not the most technical set but it is fairly resolving and the detail is there for sure. The one thing I haven’t mentioned yet is the bone conduction driver and how it affects the sound and to be honest I’m not quite sure how to describe it. I feel like a lot of the added body and rumble/texture I hear is due to the BCD but it’s hard to say.

By far the stand out aspect of this IEM is it’s spatial properties, the 3D staging is something I’ve heard about the Mest line previously and now I realize how special it is. Very holographic almost spherical stage with a healthy width and height, but what really stands out is the imaging prowess, it is laser accurate in placement of instruments, and the sense of space between notes and layering of sounds within the stage is truly magical imo. This is the best imaging I’ve heard in a IEM so far. I want to say these unique spatial properties have something to do with the bone conduction but it’s hard to tell for sure, I have seen other people attribute it to the BCD though so that’s what I’m going with!


Disclaimer: Cables are very subjective when it comes to perceived sonic differences, in most cases these differences are so slight that it is negligible, in other cases despite it being so slight depending on the person and their listening skills and experience it can mean a world of difference. It depends on the listener.

The Indigo comes with a great stock cable in the M3, like previous UM products they have gone with a PWaudio sourced cable and it has worked out very well for them here. The M3, besides being quite the looker with unique hardware that makes it look premium, it also feels exceptional from a ergo standpoint. Nice and supple with zero stiffness and fairly light despite feeling and looking quite substantial with it’s 4wire design. The sound is highly subjective of course but I find it to be infallible, it does what it needs to and gives forth a excellent sonic experience. All of my impressions thus far have been with the M3 so refer to those for specifics in sound. Overall this might be one of my favorite stock cables.

The Copper+ is a very nice cable, super premium and sounds great. It is a bit on the stiffer side due to the unique wire makeup and extra shielding that involves and has noticeably more heft, so ergo goes to the M3. Sound wise for the Indigo vs the stock M3 it adds more bass impact and a tad more extension down low as well as a slightly wider stage. I hear a bit further into the stage as well so depth gets a bump likely due to the improved noise floor which is nice but the M3 already had a great black background so this is just icing on top. The mids stay very similar but with maybe a bit more clarity and treble has a little more energy up top but nothing major. Overall it sounds great with the copper+ but I do think that the added sub bass and mid bass impact along with the changes to the highs might upset the balance a bit but sorta splitting hairs.

With these comparisons in mind, I personally don’t see the need to upgrade the stock cable, it is wonderful as is, both ergonomically and sonically. It’s obviously been fine tuned with the indigo in mind and while you can tilt it a bit more to your preference with other cable choices I personally worry that will upset the balanced tuning that i love the indigo for.


As my only IEM, currently the Infinity is the only set I’m able to compare in depth with the Indigo, I try not to do more involved comparisons unless i have both sets on hand. Memory can be a very fickle thing sometimes and I want to be the most accurate I can be.

The Infinity is obviously in a higher price tier so its no surprise when I say that it also overall performs in a higher tier technicality wise. The one exception being the Indigo’s imaging and spatial nonsense which far outperforms it’s price point imo. The Infinity is noticeably a more intense in your face listen presentation wise with a more resolving and detailed signature, dynamically it punches you with a more full bodied dense sound. It’s really quite impressive for a all BA set to have such a feeling of physicality to the notes, while the Mest’s bass has more punch and impact characteristic of dynamic drivers the Rhapsodio sounds bigger and grander with more nuanced texture and natural tonality. The Indigo has the more prominent and present mids and vocals but Infinity sounds sweeter with a greater sense of melody and musical nature to the vocals with a more organic timbre. The treble is standout on the Infinity compared to most other sets I’ve tried, it extends high with great articulation and clarity, it gives me that sparkle that I’ve grown to love. noise floor and background goes to the Infinity, it’s just inky black and seems to go on forever so much so that I feel lost in it sometimes, stage width and height are also more expansive over the Mest with imaging being exceptional but just something about the placement and air between notes with the Indigo have it in a uniquely all it’s own position.


The Indigo is a damn fine IEM and is a great entry into the Mest family and introduction to bone conduction for me. I think it’s a terrific value at the price and only wish it was not a limited release and maybe it was offered in custom form. If you are looking for a more balanced signature with tasteful DD bass and out of this world imaging capability it is a good choice. Despite the Infinity being higher performing in most respects and being my preference I would still consider a Indigo as a good compliment for something different.


To see more discussion and experiences around this IEM, and get into the conversation yourself, check out the Unique Melody forum post: