This is an in-depth review of the Unique Melody MEST MKIII CF, a hybrid multi-driver custom in-ear monitor with bone conduction technology. It is priced at $2359 SRP for the custom red and blue versions.
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The Unique Melody MEST MKIII CF is the most mature tuning in the MEST series to date. It is less bombastic or exaggerated than what has come before with a balanced, smooth, and very agreeable sound that gives vocals a much better platform to shine.
When the original MEST came out in 2020 it struck a chord with a lot of audiophiles on a number of points; not least the performance and being one of the first high-end IEM makers to include bone conduction technology within a tribrid driver design.
The MEST MKII swiftly followed in 2021 boasting of an improved bone conduction driver design and a change in the tuning to something a little weightier and smoother sounding than the original.
And now in 2023, we have the MEST MKIII CF, and once again UM has gone with a new bone conduction driver and also increased the driver count from 7 to 9. The price has also gone up from $1799 for the universal MKII version to $1919 with our custom MEST MKIII CF sample review unit here coming in at $2359.
The Unique Melody MEST MKIII CF is a high-end multi-driver in-ear monitor with additional bone conduction technology. You can purchase it either in universal or custom format with this sample being the custom version.
Although not as unusual as it was in 2021, the MEST MKIII CF driver mix is a combination of dynamic, BA, electrostatic, and bone conduction. However, unlike the MEST and MEST MKII’s 7 + 1 driver configuration, the MEST MKIII CF uses a larger 9 + 1 driver count.
The enhanced count is primarily driven by the switch from the previous dual Sonion electrostatic driver array to a quad-array or four drivers for the ultra-highs. The rest of the configuration is quite similar to the MKII with a single 10mm dynamic driver for the lows, 2 BA for the mids, and 2 BA for the highs using a 5-way crossover.
Just to note the dynamic and BA drivers handle the 20Hz to 20kHz range, while the electrostatic drivers are more for the upper treble and air from 10kHz and beyond, (rate at up to 70kHz).
The official rating of the MEST MKIII CF is similar for impedance at 14Ω compared to 12.8Ω for the MKII but the sensitivity has dropped to 104 dB @1kHz from 112 dB and this may well be as a result of moving to 4 EST as opposed to 2.
The MKII’s dBC-s or Dual Sides Bone Conduction system has now been replaced by a silver palladium alloy design with an audible frequency range coverage between 500Hz to 16kHz which is similar to the MKII’s bone conduction coverage.
Both are piezoelectric bone conduction drivers relying on lateral vibrations of the cavity to directly transmit sound to the inner ear through contact with the skull. Hence, you see the driver at the base of the shell in the explosion diagram where its vibrations to the ear are at their most effective.
The new bone conduction driver has a thicker ceramic piezoelectric layer coating than the MKII version at 27 coatings compared to 14, which, according to UM, will enhance the vibrational efficacy of the bone conduction from the MEST MKIII CF.
Since this is a custom design you are not limited to one specific aesthetic but in this case we went for one of the two “house” MEST MKIII CF designs in red. The other choice is in blue.
Both of these creations are standard choices for the universal version though the universals are finished with metal tunnels at the nozzle specifically for ear tip fitting.
The custom design is mostly molded carbon fiber material shells which has been a stock choice for Unique Melody designs for quite a few years now combined with unique plates and rims.
Actually, if you have been following our recent review of the Multiverse Mentor or came across a coverage of the older MEST Indigo you will notice that UM has sort of come up with a formula and official design language for a number of their IEMS.
That includes both the carbon fiber weave as well as the metal rim with the plate composition and rim color changing depending on the specification.
In this case, the MEST MKIII CF does take a lot of inspiration from the Indigo version of the MEST from 2021 with a beautiful dark red fruitwood plate set into a shiny gold rim frame with a tonally matched translucent carbon fiber reinforced shell underneath.
The finishing is perfect also, with nothing in the way of blemishes or air bubbles on the shells.
The form factor of this MEST MKIII CF custom version is more or less the same as the MEST MKII. Same size, same curvature with one or two technical differences.
The first is a more obvious change with the venting hole moved from the front plate to a more discrete dual pinhole venting system on the rear side of the MEST MKIII CF shell.
The second is a change in the bore, (tube), system with a quad-bore exit on the spout as opposed to a tri-bore on the MK2.
The sizing of the bores is also different with three small and one large on the MEST MKIII CF as opposed to 2 small and one large on the MEST MKII. I have to presume the additional bore is for the additional 2 EST drivers inside the MEST MKIII CF.
Comfort & Isolation
The MEST MKIII CF custom shell should be larger than the universal version, as customs normally are, but as customs go it is about mid-sized and very accurate for fitting purposes.
If you are considering coming from the MKII and retaining a custom design for the MKIII CF then the fitting experience is almost exactly the same.
UM loves fitting its custom units with deep and long spouts or what I tend to call a “Pro” fit for active use. These fits reach deeper and closer to your canal’s all-important second bend which is where the performance is normally considered optimal.
I also noticed a slightly stronger curvature on the upper rear of the MEST MKIII CF shell compared to the older softer contours of the MKII shells which might suggest the printing process for the shells is even more precise than before.
And yes, they felt really secure with similar levels of excellent passive isolation to the MKII. The pressure in the ear canal is just right for a custom also, not too thin on the nozzle that they end up moving and creating gaps in the seal when your jaw opens.
They isolate just slightly behind the custom-designed Maven Pro we reviewed earlier this year but since that has no dynamic driver and thus no venting it should be no surprise. Hybrids generally lag behind all BA as they require those venting ports but this one performs above expectations.
Now, this is where I suspect there will be some debate, and indeed such is the feedback that dealers now offer the MEST MKIII CF as an option with or without the stock cable allowing you some additional budget to buy your own cable or go with what you have.
Well, aesthetically it’s beautiful, to be honest, and retails on its own for around $699 so not a throwaway cable either. You get two options, a ‘Melon Red’ finished version which is the one we have here, or a cobalt blue with the blue-themed alternative shell.
The red comes from the external nylon jacket and technically it covers the wiring all the way up to the splitter. From there it is finished in lightweight black PVC tubing and finished with a soft springing memory coating for placing behind your ears.
Inside is a 4-core 26AWG OCC Copper which is fairly standard for decent aftermarket wiring and one I presume is done in collaboration with PW Audio as were their previous versions with the MKII.
The termination on the MEST MKIII CF stock cable sample here is a 4.4mm balanced Pentaconn with UM’s signature indented barrels for both the jack and splitter with matching chin cinch. All are impeccable in their design with plenty of pop from the color scheme and excellent durable strain relief.
And why the negative feedback? In short, the handling from the internal geometry with the cores placed side by side or in parallel as opposed to braided gives it a very flat appearance. This flatness makes handling tricky with the cable from ‘kinking’ quite a lot when trying to control the shape to suit your needs.
Packaging & Accessories
The MEST MKIII CF marks a brand new packaging experience for me and UM custom IEMs. Typically, they are quite compact or use the jewelry box sliding shelve design.
This time the box is a little bit bigger with a high-impact graphical design on the outer vinyl layer and more of a display box type with a lifting lid design on the inside to show off everything in one glance.
Because this is a custom design you will not get any ear tips so the accompanying accessories are a bit simpler with a branded cleaning cloth and blue/green leather IEM organizer strap that also matches the color of the leather on the puck-style carry case.
I must say I do like the quality of the finishing on the MEST MKIII CF carry case. Leather puck cases have been done before but the padding on the inside seems a little thicker than most providing excellent protection.
There is a decent amount of space also with its relatively tall dimension. Enough to squeeze in the cable and the drivers inside a protective blue mesh pouch.
One thing I would call out is this package seems fitted for the blue MEST MKIII CF package with a lot of blue on the outside box design and blue for the mesh protectors. I would have liked to have seen a red alternative for this sample since the driver color scheme and cable are red-themed.