Westone UM 56 - Reviews
Pros: improvement in fitment and isolation, natural seal resulting in sound improvement
Cons: pricey, takes longer to insert/remove from your ear

Before I start my review, I would like to Thank Westone for providing me with UM56 review sample (while audiologist impressions were covered by me) in exchange for my honest opinion.

As I have mentioned in most of my IEM reviews, eartips selection plays the most crucial role in getting the best sound out of your in-ear headphones.  Some people mistake this process, also known as tip rolling, thinking it's only necessary in order to find a better fitment, and they are right to a degree.  The fitment will also control a seal which has a direct impact on the amount of bass and high frequencies.  We are born with a unique ear canal “design”, and a correct selection of silicone or foam eartips helps us with IEM universal fitment.  But nothing can substitute a custom made eartips designed specifically from a mold of your inner ear, a similar process used in Custom IEMs (CIEMs).
There are some advantages and disadvantages when it comes to CIEMs, but one thing for sure - you can either have custom or universal design, but not both as the same time.  With introduction of UM56, Westone came up with a way of bridging this gap using a very practical solution.  Since all of their latest W-series and UM-series IEMs have the same narrow nozzle and universal eartip fitment (equivalent of Comply T100), now you can order a custom silicone eartips set that going to fit your ear canal like a glove and will go on any W-/UM- shell.
First of all, you need to visit your local audiologist and request an impression of your ear canal, just like you would for any CIEM.  If you need help, visit Westone website where they have a database of participating local Hearing Professional specialists.  Most of the time your will be able to order these custom eartips right from your audiologist office where you can get the best deal on the combined package.  During my visit where I got 3 sets of impressions (cost me only $25 insurance co-pay), the whole process took about 15-20min (for all 3 pairs), and I had them ready in the box to be send out to Westone right away.  For those who are interested, you can read more about how impressions are taken here: https://www.westone.com/hhc/index.php/earpieces-and-the-ear/about-impressions  
In-ear impression.
Though waiting time could vary, I had my custom eartips ready and sent back to me in about 2 weeks.  The actual in-ear impression mold was quite big since it captured a large portion of my inner ear canal and outer ear shape.  I didn't know what to expect and was a bit worried that custom eartip going to be so big that it will make IEM to stick out of my ear.  To my pleasant surprise, the eartip turned out to be small and actually a little bit longer than the largest star tip.  I chose a smoked gray color, though Westone has a huge selection of custom colors, for the reference found here: https://www.westone.com/defendear/index.php?option=com_content&view=article&id=96&Itemid=120
It had a very smooth surface with a rubbery feel on outside and a uniform narrow sound-path inside, as wide as headphone nozzle.  The eartip opening was fitting the nozzle snuggly and still allowed a little degree of rotation, but it was tight.  Also, I like how it had a short attached string piece with an easy to grip round endpoint - very convenient when you need to remove earpiece.  Actually, it was a very clever idea since it's quite possible to remove IEM while leaving the eartip behind.  Pulling on this short string can remove earpiece easily and safely.  Also, each earpiece had a clear L/R marking on it.
Design details.
Next to star tip.
Fitment with W60 and UM Pro 50.
As I mentioned before, the size of UM56 is a bit longer than orange-marked star tip.  But regardless of a size and due to a custom nature of the shape, it went in deeper which resulted in a flush mount, even better than with a star tip.
W60 fitment (with Star tip and UM56 tip).
I do have to admit, using W-series or UM-series with UM56 custom tips wasn't as quick and easy as it was with universal eartips.  The caveat here is that you are dealing with a 2-piece design, and a custom-shaped earpiece is not 100% permanently aligned with a shell of IEM where it rotates around the nozzle.  It's definitely not a straight-forward in-and-out like with silicone tips or going in-and-out with one piece CIEM.  Here, you do need to twist it a little bit every time you insert these in your ears to micro-adjust the fitment.  I think it will work better after a longer break-in period when eartip should rotate looser around the nozzle.  This way you can focus first on a proper insertion of eartip and then adjusting rotation angle of the shell to fit inside of your outer ear.
Another lesson I learned, since I don’t have any previous experience with CIEMs, a brand new silicone tip needs to be lubed up a bit to avoid initial friction with your inner ear.  Coincidentally, Westone included a packed with a water based solution for your ear, and I regret about ignoring it until I realized what it was for later.   Moving forward, I didn’t have to use it as often, but probably a good idea if you feel the eartip or your ears being dry.  As you can see, there is definitely a bit of maintenance and some time consuming steps involved when fitting them in your ears.
So the big question, how do they affect a sound?  When I go through different sizes of Westone star tips, it's always a science experiment where a tight seal can enhance (to an exaggerated level) bass while also attenuate brightness of upper mids/treble. With looser seal, bass can get attenuated down and disappear completely.  With foam tips, you attenuate upper frequencies down while enhance lower ones.  With UM56 custom eartips you have a perfect fit with a natural seal that creates a perfect balance between low and high frequencies, limited only by a sound signature of IEM rather than external fitment factors.  But overall, I felt a sound became more balanced, with more airiness, and even a little more sparkle.  Low end definitely felt a little tighter and cleaner, and I actually noticed a slight improvement in upper mids/treble clarity.  Sound signature was still the same warm Westone house-sound, don’t expect that to change.  Also, I didn’t notice too much change in soundstage width (W60 and UM Pro 50), but slight reduction in staging depth with W60, while more intimate staging depth of Pro 50 remained the same.  Furthermore, I felt no pressure inside of my ear canal and was able to enjoy a long time listening session without my ears getting hot or sweaty.
Without a single doubt in my mind, I found UM56 to provide a noticeable improvement in fitment and sound quality when using my Westone IEMs.  As a matter of fact, considering the same nozzle size you can also use UM56 with Shure SE-series as well.  So, is this a must have for every Westone and Shure user?  It definitely makes sense for those who want to enhance a sound quality of their $400-$1k headphone investment.  But I don’t think it’s for everyone or every listening situation.  These custom eartips contribute to a very significant sound isolation which cuts your surround awareness, and they are not for those who enjoy short listening sessions and remove their headphones quite often.  It really becomes a hassle when you constantly take them out and put them back in and have to go through micro-adjustments all over again.  But if you are traveling a lot and require a good isolation during your extended trip, or want to dive into a deep uninterrupted listening session, or a stage musician or someone who enjoys active lifestyle with a secure IEM fitment – these custom UM56 eartips can really take your Westone or Shure IEMs to CIEM level!
This is a very useful review.  Thanks.
Great review, I was literally emailing Westone just the other day regarding getting a pair of these!
This just makes me want to hurry off to get my impressions that bit more.
JUst need to wait for this head cold to pass.
Do you get major bone conduction / discomfort when walking with these? And wouldn't the tiny plastic nozzles
on the Westones easily break with these custom tips on?
Pros: sound just blossoms, full sound stage, gobs of air/transparency
Cons: takes some getting used to
I personally prefer the sound of the "Westone" series to the "UM" products.  I use my IEM's for listening to pre-recorded music.  The sound of the UM series is very good, but the WESTONE 4R is the closest I have come to the sound of my FOCAL speakers.  While the sound was pleasing when using the COMPLY foam tips, the UM56 custom tips took  everything up a level.  The bass is still prominent and powerful but just a tad more solid.  It's like a touch more pillow in the kick drum and a little low-mid rolled off the bass guitar and a slight bump across the low frequency spectrum. The mid-range which was stellar to begin with became more controlled as well.  Transients were more defined and notes more delineated.  Staccatos were sharper and legatos were smoother. Highs disappear into the stratosphere. There is no grain, edginess, aggressiveness, etc.  The high end is reminiscent of the QUAD ESL speaker. In summary, the UM56 tips just allow you to hear more of what the armature is doing. 
  • Like
Reactions: JimNoyd