Westone UM3X / 3X - True Triple Armature Drivers In-ear Monitor Professional Earphone

My setup for this review is Foobar2000 + WASAPI Event Out -> HRT MicroStreamer -> UM3X RC with Moon Audio Silver Dragon
 
I traded for the UM3X about two weeks ago and I haven't used another IEM since.
 
Currently listening to Classic Sinatra II in FLAC. Everything is well separated, to the point that it feels about as well-differentiated as my HD598 and DT770 in terms of instruments being presented distinctly from one another and not bleeding into each others' space; obviously soundstage size is nothing to speak of by comparison, and the UM3X is on the smaller side as far as triple drivers go, but I think that makes its ability to separate sounds amost even more impressive.  Brass, strings and vocals all have appropriate body without sounding overly throaty or bloated, and of course never bleed into each other. Frank's voice really sounds like it's coming straight from one of those old-school microphones. This is a real pleasure.
 
Vivaldi's Four Seasons with Joshua Bellas first chair, also in FLAC, is next. The bass and cello notes have much more authority and power than I remember the SM3 ever having, for sure; you get that real FEELING of the instrument, whereas the SM3's more delicate sound was more about listening to the bass. This sounds much more "live" in terms of the textures and immediacy of the sound. Those rapid viola lines in Spring are not quite as crisp and distinct as I remember the SM3, but they still sound more "real," with better accuracy and timber. Violins also don't have the same exaggerated feel; they really do peak sometimes and give you that euphoria, but it's not exaggerated. The lack of the SM3's color is really appreciable here.
 
Now listening to Beethoven's Bagatelle in A Minor in FLAC. Pianos are soft and subtle, but not incredibly crisp here. A very relaxing listen.  Everything sounds fine. I've heard phones that definitely have a more atmospheric effect with a piano, which is really important when you're only working with one instruments IMO. There are no SERIOUS faults here, but it's not the UM3X's strong suit.
 
Bassnectar, however, is. Listening to Underground Communication in  FLAC,  and the bass is just right here: enough oomph to let you feel it, but never overshadowing other sounds, of course. The UM3X is great for giving bass-centric music plenty of power, but not overshadowing other elements of the music, which is a quality I sought for a long, long time; the SM3 served decently in this regard, but just never felt quite powerful enough; it was punchier than the UM3X, but didn't have the same sense of realistic decay and reverb. Treble roll-off shows a little bit, but not enough to detract from the music IMO. It will never be as sparkly as the TF10, but personally I don't mind, as I prefer a smoother, slightly sound in general. There isn't any information missing, so it sounds good to me.
 
More EDM: Juno Reactor's Pistolero in FLAC sounds great as well. Again there could be a smidge more treble energy, but I think that's being picky; those who prefer a brighter sound might disagree. Strings have good pluck and the UM3X keeps up with everything admirably, never missing a beat, and giving that psytrance bass punch just enough oomph without bloating it or sounding artificially tight; some people prefer bass that is tighter or punchier than this for faster-paced, more intricate EDM like Juno, but I think the UM3X's more full-bodied low end, which has longer than average decay for a BA, sounds like a more refined, better controlled middle ground between a "technical" sound and what you actually hear when you witness live EDM. You can't feel it thump in your chest; this is an IEM after all, but it's tactile enough that it does justice to the overall sound. And those female vocals...the UM3X makes you feel like you're right there on the stage. Loving it.
 
Anyone who says the UM3X is lacking in soundstage needs to listen to Mozar's Die Zauberflote (The Magic Flute) Scene 2 - Eine schreckliche Nacht! in FLAC or better, through a decent source, and tell me that distant rolling thunder doesn't catch you just a little off guard. This was the first combination I used to test my HRT MicroStreamer (which synergizes very well with the UM3X for anyone interested) and I literally thought there was a thunderstorm outside! Listening to excerpts from the rest of the opera, the UM3X obviously excels with vocals, and provides proper imaging to give a sense of the on-stage interaction, though not with quite the same drama as some phones with bigger soundstages.
 
I'm coming to the UM3X from the SM3 and TF10, and although I occasionally miss the SM3's speed and soundstage, the UM3x gives a less colored, more tonally accurate sound that I see as hearing the music rather than the earphone, which is something I'm coming to appreciate more and more as my taste in headphones has gradually changed from bassy/v-shaped towards neutral/balanced and slightly midcentric. The UM3X also never distorts, which was a problem I had frequently with the SM3: it would sound thin and a bit weak at higher volumes: its dynamic sound would begin to falter, bass would start to sound hollow, and the soundstage would compress when I cranked the volume, never really keeping up with what I wanted for my noisy commutes. I can push the UM3x to the limits of my hearing, and its signature and presentation remain consistent; the bass never gives an inch. And while two weeks with a used set doesn't give me much room to comment on durability, I can say without hesitation that the UM3X is made with infinitely higher quality materials just by holding it; the flimsy shells of the SM3 v2 would flex with a small pinch, whereas the UM3X feels solid as a rock by comparison.
 
Overall I definitely recommend the UM3X for anyone looking for a largely neutral sound with slightly elevated bass. It does full justice to music emphasizing strings and vocals, and performs well with electronic music if you don't have a need for laser-like treble. As a complete package, it is by far my favorite earphone I've owned to date.

You might say I’ve been on a quest of sorts. I’ve tried many mid and top tier universals, searching for something I can be content with for the long haul; something I can use on my daily commute that’s not only satisfying aurally but also in build and fit, with a pleasing aesthetic.

Sound wise, I thought I might have found it in the Hifiman RE262 but ultimately is was too light in bass for my tastes and the new modular cable was too heavy and flopped around, constantly reminding me of its presence. From that experience I knew I had to find something with really spectacular mids and better bass weight and impact. Having an admitted bias for dynamic drivers, little did I know I’d find it in a balanced armature design!

When it comes to pliable, easy to deal with cables and sleek, form fitting housings, no one really holds a candle to Westone. I’ve owned both the 3 and 4 in the past and absolutely loved the build, fit and aesthetic but always found something to complain about in the sound. Having read that several head-fiers, while ultimately preferring the 4 to the UM3X, thought the UM3X had the better mids with more bass quantity, I knew it was something I should give a try. I had thought the 4’s mids were pretty darn good – intimate, warm and involving, so if the UM3X could do it better, it sounded like a good candidate on my quest.

I decided to buy from Earphone Solutions, for their reputation as an outstanding authorized Westone dealer and the 2 year manufacturer warranty. I also opted to buy the removable cable RC version. Right from the beginning I got a great fit, with great sound using the standard Westone gray flex sleeves but just to be sure, I tried all of the supplied tips, plus several others from my box-o-tips. Yep, those gray tips are perfect.



My initial impressions, for the most part, still hold true now after having spent many more hours and commutes with them. Here are some of my initial impressions I shared with a couple of friends and fellow head-fiers:

The overall presentation is pretty natural sounding, perhaps even more so than the W4. I think it is as technically proficient and just as accurate as the W4, however the UM3x can appear a little sterile, whereas the W4 was maybe more musical.

I like the W4 treble a better. It’s smoother and more detailed. The W4 is warmer and nearly as intimate in mids but the UM3X is clearer and more detailed throughout the midrange. The UM3X wins in bass hands down. It's the most satisfying bass I've ever heard to date in a BA. If the W4 had this bass, it would have been a masterpiece for me.

The UM3X separation and layering is unique and a step better than the W4 but the W4 has a wider soundstage. I'd also probably give the W4 the edge in instrument realism due to its treble. Fit is significantly better than the W4 and less tip dependent. I put on the med gray flex tips and I'm done.

As I said, those were my initial impressions and they’re still pretty accurate to how I hear the UM3X. Here are some additional thoughts after using them for significantly more time:

1. Great forward guitars; nice thickness and decent bite.
   
2. Bass guitar is prominent, textured, musical and the thumping backbone to the music.
   
3. Drums sound excellent: nice tight toms; snares really pop; shimmering and sparkly rides, hi-hats and cymbals without any piercing or fatiguing aspects.
   
4. Very intimate soundstage with really good depth. I haven’t heard this much depth in universal BA’s before.
5. Unlike the SM3, there is space between backing and lead vocals, instead of being placed on top of each other.
   
6. Instrument realism and dynamics improve with a cleaner, more powerful amp.
7. Incredible instrument separation; each instrument is on its own layer and seems to rise up and out of the music if you focus on one in particular.
   
8. Vocals have a very analogue/vinyl feel and presentation to them. Always up front and center.
9. With the right recordings, vocals are incredibly intimate; as if the performance was being made exclusively for you.
   

So is this the end of the quest? Well it’s the end of this particular quest. I’ve finally found a universal that I thoroughly enjoy from top to bottom, use daily and entertain zero thoughts of selling. However there is always room for a new quest: Vsonic GR08? Cardas Mirror? AKG K3003? FitEar To Go?

I love this hobby!

Got these on Amazon for $285.00 while there was a deal going on. 
 
These IEM's are great.  They have a healthy amount of bass but its still more or less detailed.  The mids are very nice to listen to, and the highs are very separated and detailed.  
 
The lower end sounds a lot like my HD650's.  The mids are hard to compare to anything, and the highs are almost as detailed as my K701's but have the sweetness of my HD650's.  Its a nice compilation all together and I highly recommend them to someone hoping to spend under $300 on an IEM.

These things kick ass. I can't find much words to describe them, other than real. All the instruments sound incredibly real. I'm currently rocking out to coldplay on them through my iPhone 4 and a Fiio E7. They're truly incredible. My only two complaints are that for the first few days (like only really 5) they hurt if you're not used to these type of earphones, and that the included tips aren't great. One pair worked pretty well, but I wound up using the tips from my Klipsch S4i's (they sound meh, but the tips are a dream). When you listen to these, you forget about FR - it's all in the instruments. Everything sounds like someone's playing it in front of your head - listen to Led Zeppelin's D'yer Mak'er and you'll see what I mean. It's really like you're sitting at the drum set. Granted, they're expensive, but incredible. I'm loving these.

I agree with the other reviews: outstanding mids, clarity & separation; slightly emphasized bass that's tight & accurate.  There isn't anything to say that hasn't already been said on that front.
 
These were not 'all that and a bag of chips' to my ears.  They are obviously very high quality & there are no true faults, especially when their true purpose is kept in mind.  The sound signature was not as balanced or natural sounding as I prefer, the mids are extremely forward & in your face, instruments such as guitars, alto sax or any other 'mid' focused sound are less in your face & more your face is IN the instrument.  I think that these are great canalphones, especially for those that prefer a very forward sound.  The highs do roll-off & seem relatively recessed & cold, but again not a fault considered the intended purpose.
 
I would not want to discourage anyone from purchasing these, though I would recommend purchasing from somewhere you can return them due to the 'love it or hate it' sound signature.  It performs excellent & as intended, but could be very unpleasant to the wrong person, definitely not a 'please everybody' IEM.  I don't view them as overpriced for $350ish but I also don't view them as a steal.  They have many competitors & I think this is a price range that should be deeply & thoroughly explored when searching for a specific sound.

Great quality, sound stage not as good as Shure. Love these headphones even more than my UM2's

 
 













 
So that's exactly what you get in the box (at least at this point in time.) Hey, I expected less tips, so it was great to get a bunch of em. Quite a few in various sizes and materials. But I will probably never use the ones that came in the case, because I use Shure Olives and love em.
 

 
One thing I thought would be bigger is the box. As you can see in the pics, it is quite small, but I guess Westone decided to save some packaging and keep it little. No biggie. The Triple.Fi 10 box was waaay bigger, but so are the Triple Fi's themselves and their case This packaging stuff makes no difference to me anyway.
 
I like the different style case, but not sure yet if it is any more useful than the UM2's round case. Nice to have something different though, as I have been using UM1 and UM2 round cases for years.
 

 
Build quality looks great. Sturdy, and future proof with the removable (IE replaceable cable.) This also gives the option of upgrading to a higher quality cable if needed. But this cable is great just like Westone is known for. No microphonics that I can notice anyway.
 

 
It does have the mold-able wire in the first few inches of the cable by the earphones. Not sure if I like this, but when I get to moving around on the stage I may find it more stable. Never had much problem with the UM2 cable, but I did have to adjust it sometimes during or after fast songs where I play guitar and move a lot. We'll see...I sorta don't like the moldable feel around my ears though. it seems a little harder on the skin. Didn't like it with the Triple Fi's either, but I think it can easily be gotten use to, and for home use i doubt it would ever be a real deal breaker for anyone.
 
Here are some pics of the UM3x in my ears:


 
I am listening to some of my music in iTunes on my Macbook. So far have gone through Some Jason Mraz, John Mayer, Rascal Flatts, Sandra, McCracken, Kieth Urban, Lincoln Brewster, Jim Brickman, and some old school Journey and Def Leppard.
 
Initial impressions are that these are very honest monitors and sound incredible and very neutral and balanced to my ears. They pretty much reveal anything..Good or Bad. What I mean is..like on a Sandra McCracken tune which is like Irish Folk Acoustic stuff, I could actually hear Sandra go flat at the end of a verse where she got a little lazy vocally and missed it just a bit.
 
I notice things that sound "big" in the UM3x, that I never heard enough of in the mix with the UM2, but did hear in a different way with the Triple Fi 10. I guess the sound stage being bigger then the UM2 helps a lot. The UM2 is a very good sounding IEM in my opinion, and probably overly sufficient for most musicians. It excels because it does sound great on stage, yet is still affordable especially on the pre-owned and ebay market. My impression in comparison to the UM2 is that the Bass is immediately noticeable as being stronger (similar to the Tripe.Fi 10), but in a balanced recording studio monitor sort of way, that is not overpowering. The bass is also a little more clear and detailed to my ears than with the UM2. I imagine this can also be shaped with various tips, but I really like it so far with the Shure Olives.
 
The treble is perfect to me so far, but I had no complaints in this area with the UM2. After several hours of listening. No fatigue at all. The highs are crisp without being piercing and that is a great thing for an IEM to be able to pull off IMO. There is just more of everything! I am honestly hearing instruments, vocals, percussion, and effects that I never even knew were in many of the songs in my iTunes Library. Part of that is because my ears are not fatigued as they were with the Triple.Fi 10.
 
I absolutely loved the UM2 for live band use, and I think it is pretty much the perfect IEM for on stage use for vocalists, except that if you are a drummer or other instrument player it lacks a bit in instrument detail, that you could really use to help play tighter and with more feel. But it is great at bringing out vocals sitting in that mid frequency range, and great for vocalists to be able to hear their voices clearly to better sing on pitch. I think the UM3x has a similar feel in the mids, but just has a little more of everything, and a little more detail in vocals.
 
On guitar and drums stuff, I can hear things so clear such as the sliding of the hand on the strings, percussive playing, pick hitting the strings, etc. Drums are the same way. I hear the drum tip hitting the cymbal and the kick hitting the drum head in some recordings. I hear delay effects, reverbs, and chorus that I have never even noticed in these songs I have listened to many times before.
 
Honestly I could say some of the same great things about the Triple Fi 10. They sound great also..but a different sort of great. The Triple Fi 10 was definitely not as neutral to my ears. Powerful bass and detailed high end. But so much high end detail was harsh to my ears and fatiguing, And with that IEM, I could never get a good fit. It actually hurt my ears after a short time no matter what tips I used, and there was no way I could use them on stage in our venues, because of the visibility issues. They just stick out way too far for me. I realize most people would never have to deal with that, but I am a musician that is filmed regularly in our services, so it is much better to have less visible IEM's on stage, so that when you are on the jumbo screens you don't look like Frankenstein with bolts coming out of your ears

If a regularly video'd musician loves the Triple.Fi 10 (and there area many reasons to love them), i would suggest getting custom molds if nothing else for the visibility issues.
 
Another thing I would say is that the UM3x pretty much reveals the fact that there is a loss of quality in the music such as artifacts that are in compressed recordings. The more compressed your music is..the more artifacts and consequently, because of the compression, the less detail you will hear. So this may not be the IEM for folks who want something to just make music sound good no matter what type of compression is used. Don't get me wrong..compressed music still sounds good, and I would rather notice that the music has been compressed and still get all the bonuses that come along with the UM3x's sound than to buy a less revealing IEM.
 
Cuz here's the thing...just like with a good set of neutral studio monitors, when the recordings are not compressed or you are listening to these as IEM's on stage playing with a live band...they are gonna be revealing all the good stuff too in a balanced way! For me that is exactly what I am looking for.
 
So those are some of my first impressions and pics. Hey...if the price of admission is a little steep..at least you get this nifty Westone sticker in the box:
 

 
   Update 2: I have been using these now for over 3 months and my impressions still stand as with my detailed statements above and comparison. I have been using them on stage in a live band as IEM's with an Aviom monitoring system and also using them with my iPod Touch 4th Gen. There really didn't seem to be any burn-in change that I can hear, but changing to Shure Olive tips made a lot of difference in comfort and isolation. I have no plans of getting anything else for stage use!

UM3X Review - starting from scratch.  
 
My rating is among other universal IEM in any price range, but not vs custom IEM.  I consider a 5/5 to be the best that all universal IEM strive to reach, which I may not have heard yet.
 
I've posted in the past that I liked the UM3X almost as much as the W3, where most of my comparisons were done with my UM56 tips which tend to equalize the disparity a bit between these two IEM.  I've compared the UM3X with W3 at Canjam 2009, Colorado meet July 2009, and then my most recently in Oct 2009 at RMAF (after losing my 1st pair of W3 and UM56).  When I compared these two IEM with Complys tips at RMAF, I walked away with another W3.  Since then I had forgotten how good the UM3X sound, but I picked up a pair with the removable cable  last Friday so that I could use them with in balanced mode with my Protector amp.  But before tonight I hadn't even tried them with the Protector or Pico Slim, because I've been enjoying them so much with my Macbook > Nuforce uDAC-2 and plain old iPhone 4 headphone out.  They don't beat out my ES3X or new ES5, but they definitely perform very well for a universal IEM, coming out ahead of my Livewires T1 or Alien Ears C3 customs (and my SE530 in a custom shell).
 

 
One of the first things I noticed was that while they are just as efficient as my W3 or ES3X, they have noticeably less hiss when plugged into my ALO Amphora amp.  With the volume turned down I can hear more hiss with my W3, and my ES3X reveal so much hiss that I stopped using them with the Amphora.  But somehow my UM3X are fairly quiet with the Amphora (and so are my very sensitive Westone ES5).  The hiss with UM3X is below the level of my chronic tinnitus, and not intrusive at all.  With my other quieter amps the UM3X are silent.  I used to recommend the IE8 as a good universal IEM for the Amphora since they didn't hiss with it, but now I can also recommend the UM3X too. 
 
I was quite pleased to find that my UM3X with removable cable came with the complete Westone fit kit, with a wide variety of tips included, and not just the Complys.  I don't know if this comes with all of them, or just the special package that was meant for me.  I've settled on using either my UM56 tips or the single flange silicone tips, but I wasn't getting a good seal with the short Complys that were pre-installed on them.  I typically keep my custom UM56 tips in a carry-case with my W3 because those really benefit the most from custom tips (almost demand them I should say, although long Complys are my second choice with W3).  But I like the single flange silicone on the UM3X more than on the W3, and they're quick to insert into the ears.  So I'm fine with leaving the UM56 paired up with the W3 and just using silicone universal tips with the UM3X.  For the benefit of others who don't have the UM56 custom tips, I will compare the UM3X to the W3 here while using universal tips only, and this makes a difference over which IEM I prefer.
 
The UM3X frequency response is definitely more neutral than the W3, and I was afraid that they would start to sound boring after a while, but I've listened to them many times since I received them and they haven't disappointed me yet.  With the single flange silicone tips the UM3X seem to sound best with a shallow insertion, while the W3 sound best with a deep ear canal insertion.  So, switching to the W3 with the single flange tips pushed in deeply, I find the bass to be similar in depth and power, but the W3 are somewhat boosted in the mid-bass vs the UM3X.  The mids of the W3 are not as forward as the UM3X, but not terribly recessed either.  The UM3X highs are slightly muted vs the W3, but not dark in any way, and not as aggressive as the W3 can be with the wrong tips or wrong insertion depth.  The UM3X have better treble sparkle than the IE8 that I got rid of at RMAF, which seemed to have a recessed treble in comparison.  
 
Overall, I would say the UM3X have just the right amount of bass, mids and treble to strike a nice natural balance, while the W3 have more of a "fun" frequency response if using the stock tips (but more natural with UM56 tips).   I also tried low bit-rate downloads with the UM3X (Breaking Benjamin, Dave Matthews), and the UM3X seems a bit more forgiving of low bit-rate downloads than the W3.  This also varies somewhat according to what amp I am using, and the Amphora was best with UM3X, closely followed by the Pico Sim and uDAC-2, then DACport, iBasso D4, iPhone 4 headphone out, with the Protector last but still in the running.  With high quality recordings in lossless, the amps grouped more closely together in performance.
 
Tonight I started by listening to Eiji Oue Minnesota Orchestra "Rachmaninoff Symphonic Dances" via Macbook Pro > uDAC-2 and the UM3X sounded very immersive and detailed, smooth and musical without any etch, with nice deep bass and ambience that gives the venue good space and size.  The presentation is more like being in the 1st or 2nd row than 10th row like the W3 ("mid-hall" if the W3 are using the single flange tips with shallow insertion).  But they're not so forward as to place you right on the stage.  And the depth changes depending on the recording, so I think that maybe they do reflect fairly well what the producer had in mind.  This particular recording is very dynamic, and in the louder parts I kept thinking "this is gonna disturb my wife, I better turn it down", and then I'd remember that I'm listening to an IEM.  So, I'd have to say these are pretty transparent sounding!  These are noticeably more transparent than the Monster Turbine Pro Copper that I had here on loan last week, or my Triple.fi 10 Pro (TF10Pro).  
 
Changing to Eva Cassidy "Live at Blues Alley" with the W3 still in my ears, I can hear their mid-bass boost more easily.  However, the vocals are rich and present, and not recessed as some have claimed (unless I pull the W3 out so they are inserted less deeply).  Switching to the UM3X with this same music I find the mid-bass to be a little more tame and controlled, i.e. better balanced.  Although the UM3X have slightly less impact and power in the mid-bass, they go down just as deeply.  This bass levels are at least on par with other IEM like the TF10Pro, but without the colored mid-bass of the TF10Pro.  (note - the W3 bass is closer to the UE11Pro.)  While more forward sounding than the W3, the UM3X mids don't jump out at me as being too forward at all, although they do put me a little closer to the stage than the W3.  The TF10Pro mids sound recessed and lifeless in comparison.  The UM3X's more forward mids don't seem to hurt the UM3X soundstage size, which still remains wide and deep for me.  Typically the uDAC-2 amp has a slightly smaller and more forward soundstage than my opamp rolled iBasso D4 or D10, Pico Slim or Amphora, but the midrange presence is still just about right when any of these amps are paired with the UM3X. 
 
I'm always looking for synergy with my source/amps, so I tried a few (but not all of them yet).  Switching to the Pico DAC > Protector amp with balanced TWag cable, I find the sound to be slightly more aggressive than via the uDAC-2 (due to the amp), along with a slightly bigger sense of space or separation.  I've heard this same aggressiveness in the Protector with other phones as well, and it sounds better with HD600 than HD800 for example.  Strangely, the Protector's slight aggressiveness in balanced mode is improved when using single ended mode, but the power and soundstage suffer in single ended mode so I don't typically use single ended mode.  While I think the Protector is a better match for other phones that benefit from it's more aggressive sound signature, it's still enjoyable with the UM3X - just not as much.  My ALO Amphora is also plugged into my Pico DAC-only, and I moved the UM3X back and forth between Protector and Amphora a few times.  The Amphora single-ended simply sounds better with these IEM than the Protector, and again I can recommend this amp/IEM combo without reservation.
 
Plugging the UM3X back into the uDAC-2 again while still using the balanced TWag cable (with single ended adapter) the UM3X sounds a little more detailed than it did with the stock cable before.  It seems to me that the TWag cable is a worthwhile upgrade for the UM3X for some extra micro-detail, although the stock cable isn't bad at all and cables are the last upgrade you should seek after finding a good IEM, source and amp.  The TWag cable is a good reason to get the UM3X with removable cable, while the Protector's balanced soundstage is just an added plus.  If you get a TWag cable, you should consider a balanced cable with the single ended adapter, so it's more versatile in the future.  You can even get an adapter to let you use the Protector version of the cable with the new iBasso balanced amp.
 
Moving the UM3X over to my iPhone 4 > TWag LOD > Pico Slim also made me really happy.  The UM3X sound like they were made for the Pico Slim.  I believe the Slim was voiced with ES3X, and just like with my ES3X the UM3X really shine with the Pico Slim (while the Protector stands out with my JH13Pro, UE11Pro, or HD600 and HE-5/5-LE).  The bass depth and power with the Pico Slim is improved over the iPhone 4 headphone out, which wasn't bad until I directly compared the two.  The treble extension and space is also improved with the Pico Slim, and the overall presentation is more refined and immersive sounding.  The Protector in single-ended mode sounds closer to this than it does in balanced mode (I don't know why), but I still give the nod to the Slim (or uDAC-2).  Nevertheless, the Amphora that I mentioned above is even better with these.  But for portable use, the Pico Slim is my favorite amp for the UM3X.
 

 
I wondered about frequency response, and as an after thought I pulled out "Bink Audio Test CD" and ran frequency test tones.  With most amps my 48 year old ears can hear from 16Hz to 16Khz with the UM3X.  With the uDAC-2 I found there was a small bump at 2500-3150Hz that isn't there with the single-ended Protector or Amphora (likely the amp), and another at 6300-8000 that was there with the Protector and uDAC-2.  However, the Amphora was fairly rolled off for the 16Hz tones, and the only peak I heard was at 8Khz.  This is similar to what I heard with the ES3X last time I checked.  Although this 6-8K range is in the sibilant frequencies, the UM3X have no sibilance boosting properties.  Sadly, the Protector amp seems to distort with the 16- 32Hz tones (only did this single-ended), but the uDAC-2 and Amphora were clean (this was with a full charge and plugged into the wall). 
 
SUMMARY:  There is no doubt that I would pick either of these IEM over my old IE8 and most other universal IEM.  But after adjusting to the UM3X sound, I actually may prefer the UM3X just a little more than my W3, at least with certain recordings and the right tips.  For instance, after listening to Bill Evans "Waltz for Debbie" with the UM3X, switching to the W3 made the string bass stand out more than the piano, and the venue sounded a little more hollow and "echoey" to me with the W3.  On the other hand, with Led Zepellin "Mothership" or Pink Floyd "Animals" the W3 seemed a little more punchy and fun to rock out to.  
 
And switching the W3 to Complys tips or my UM56 custom tips seemed to level the playing field a little more than when using silicone single flange tips on both. The W3 I used are the limited edition #82/333 with the gold logo instead of red logo, but they sound the same as the regular W3 that are out on loan (I've compared them).  In the end, if you are looking for an accurate, detailed and transparent universal IEM, with a removable cable that can be upgraded or balanced, with good isolation and comfortable fit, then look no further than the UM3X.  I still think my W3 are up near the top, but maybe they're not as good of an all around "jack of all trades", nor quite as accurate as the UM3X are when you are forced to use universal tips with them.
 
Just for fun, a photo of the Westone 3 Limited Edition: