UM Miracle and UM Maestro

Maestro, music please!

PROS: balanced detailed sound, excellent resolution, soundstage expansion, lots of accessories.

CONS: needs a cable upgrade to make it shine, might be a shallow fitment for some.

Manufacturer website: UM. Available for Sale on Amazon Miracle and Maestro.

The product was provided to me free of charge for the review purpose in exchange for my honest opinion.


I became aware of UM in-ear monitors awhile back when I came across an old thread on Head-fi where the members got together to crowd-fund purchase of UM Miracle for a legendary reviewer Joker.  This CIEM received a lot of high praises and still listed among the top rated custom IEMs on Head-fi, though majority of the reviews are dated back to 2013 which is probably around the peak of its release.  Over the years, competition stiffened up with more multi-BA driver releases and the race to pack more drivers in a single shell.  UM responded with a few updated designs, including the latest 12-driver Maestro.

Right away I noticed that UM likes to name most of their models starting with the letter “M”, taking the craftsmanship of unique Melody to the level of 4-driver Mage, 5-driver Merlin, 6-driver Miracle, 10-driver Mentor, and 12-driver Maestro.  I’m also grateful that I got an opportunity not only to review their latest Maestro, but also to be able to compare it to Miracle.  The #1 question I get asked about multi-driver IEMs is if extra drivers worth the additional cost or if doubling the number of drivers will double the sound quality.  Hopefully being able to test and to compare 6xBA Miracle and 12xBA Maestro will answer this question.

Furthermore, considering both of the models I received for this review are universal, look nearly the same, and include identical accessories, I decided to structure my review by making unboxing, accessories, cables, and design sections common and then going into individual sound description and corresponding comparison.


Arrived in a very elegant small all black 4″x4″x3″ box, it had a glossy black print with a company name/logo on the top and “hand crafted with love” message on the bottom – a nice warm touch.  With a cardboard sleeve out, inside you will find another small box with accessories and underneath a foam cutout with all metal storage case.

I guess to keep the packaging compact, UM decided to stay away from a traditional Pelican style storage box, personalizing the unboxing experience with a custom storage case.  The only other thing on the box was a barcode label with a serial number.


As I mentioned before, instead of a common Pelican storage case used with a number of other Custom IEMs, UM decided to go with something different by offering a metal (looks like machined from a solid aluminum piece) round storage case with a powder coated finish and threaded top.  The case itself is about 3″ in diameter and 1.5″ in height, has removable rubber lining, and enough storage room for a thicker custom cable without bending memory wires.  The only problem here, once you tighten the top – I had a hard time unscrewing it open.  Upon closer examination, I found the culprit to be a rubber lining in the top cover part which tightens the seal a bit too much (like a gasket) – removing that lining piece fixed the problem.

Other accessories included a small velvet drawstring pouch – good to have but it’s too small to use with a cable attached, maybe to transport the shells by itself?  I mean, you can still stuff everything inside, but only with a thinner stock cable and by bending memory wire, a very tight fit and unpractical.  Other included accessories were a cleaning cloth – great to wipe the fingerprints off the shells, an airplane adapter (a filler, but some might find it useful), and an earwax cleaner (to clean the nozzle bores).  Due to universal fit, you also get 2 sets of eartips, soft cap all silicone XS, S, M, L set and 4 sizes of soft memory foams (non-Comply).

I do like the metal case a lot, and it actually makes a cool paper weight with a neat “UM” logo on the top of it.  But at 126g alone, plus another 26g for shells w/cable, it’s not exactly a pocket friendly storage, though makes a fine tabletop centerpiece or a secure storage on the shelf.  I prefer silicone eartips and actually found the included ones to work quite well.  At some point I did switch to Spiral Dots, but only due a personal preference since their cap is a bit stiffer and stem is longer.  Universal fit Miracle/Maestro have a rather shallow insertion and some might want to look into eartips with longer stem/core (like hybrids) to “extend” the fitment, or use foamies instead.


Both universal Miracle and Maestro designs are identical, including a recessed standard 2-pin socket.  When it comes to Custom or Universal multi-driver IEMs, removable cable is a must to allow not only a replacement if it breaks, but also to give you an option for an upgrade.  But I always recommend to start with a stock cable first and get to know the sound before proceeding with any upgrades.

There are 2 separate twisted conductors from each earpiece with a memory wire piece adjacent to 2-pin connector, stamped with corresponding L/R designator.  The y-splitter is just a clear shrink wrapped tube and another loose clear tube piece used as a chin slider.  All 4 individual conductors have a tight black silicone shielding and are twisted down to a right angled jack with a nice strain relief and a unique flat shape which adds a custom touch to otherwise generic cable.  There is also a removable velcro piece to keep cable in a loop together when wrapped for storage.  I’m pretty sure the wires are regular OFC copper.  Overall, this is a generic looking cable, a bit stiff, but no microphonics effect.

Regardless if you are a cable believer or not, which as many of you know that I am, switching to a higher quality conductors actually had a rather noticeable effect in UM sound change.  The units I received had recessed sockets, so keep in mind that a replacement cable has to accommodate it, where for example I wasn’t able to use Linum BaX cable.  Even after modifying the connector, there was hardly anything to grab on to remove it.  So I switched to Whiplash cables to try their latest TWag v3 and TWau with a new OM (over-mold) universal 2-pin connectors.

The problem with some cables w/2-pin connectors is the straight wire attachment which doesn’t have a comfortable fitment wearing cable over the ear.  Here, Whiplash designed their own angled (a little greater than 90deg) connector mold which fits over ear more comfortably, has a red/blue ID dot, and has a slimmed down collar for a perfect fitment with recessed sockets.  I switched cable a lot during my testing of these UM models, and got to appreciate this OM design since it made cable removal very easy and was still securely attached after at least a dozen of cable flips.

I will go into more details about sound improvement when switching from stock cable to replacement in Sound Analysis section, but for sure I did hear an improvement with TWag (silver conductor). When I switched to TWau (gold plated silver conductor), I didn’t like the effect with these UM iems as much since I felt the sound became a little smoother and lost some of its energy.  In my opinion silver cable upgrade had the best synergy.

Bottom line, if you want sound refinement with either Miracle or Maestro, I do recommend looking into cable upgrade.  Doesn’t have to be anything fancy or exotic costing you as much as the IEM itself, but silver conductors definitely improve the sound.  Just keep in mind recessed socket fitment.

Whiplash TWag v3 OM (over-mold) connector.


When it comes to UM design, the first thing you’ll notice is that 6-driver Miracle is nearly identical in size and shape to 12-driver Maestro.  Both have universal fitment with a thicker body and a snort nozzle.  For me personally, since I have a wide shallow ear canal, the fitment worked out pretty good, but I can see that maybe some others will require to use double or triple flange eartips for a better insertion and seal.  That could also be a deciding factor between going with Universal or Custom fitment.

The finish of the shell looks and feels like a molded acrylic material (or maybe high quality plastic mold), very smooth, and with a perfect faceplate seal where you don’t feel the edge.  Not sure if UM offers any other custom finish faceplate for this UIEM versions, but fiberglass one looks pretty good.  There were also silver letters spelling UM full name, but those were hard to read.  On the inside of the shell, you will find a model name and a serial number, printed in Red on the right side and in Blue on the left side.  It would have been great to see how the drivers are arranged, especially considering 6x vs 12x driver design, but the shells are non-transparent.

The shape of the shell fits perfectly inside of my Concha area, and I didn’t experience any discomfort during extended listening.  Of course, YMMV since it all depends on your ear anatomy.  The shell does stick out of your ear and there is no way you can fall asleep wearing these in.  With a right selection of eartips, the largest one in my case, I had a perfect seal with the maximum isolation which I found to be pretty good.

The only visible difference in the design surfaces up when you take a closer look at the tip of the nozzle where Miracle looks to have 2-bore design, with a smaller bore in the middle toward the side leaving other opening exposed like a slice of the moon, and Maestro having 3-bore design, where it looks like a smiley face.  Again, this is just an external observation because the shell is non-transparent, and I’m sure the CIEM version with a custom transparent shell would be able to shed more light into the sound tubes and the driver placement.

Design – Miracle

Design – Maestro

Fit: Miracle & Maestro (identical)


Page 2: Sound analysis, Comparison, and Conclusion.

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