If you take nothing else away from this review, this is probably the most important piece: UE 900 is an amazing IEM in almost every single technical way possible. Also to be noted, UE 900 is not really a "successor" to the TripleFi, it is an entirely different beast. I think this actually puts the old school UE users, who might have been extremely happy with the Triple.Fi, and might have been just looking for an aesthetic or ergonomic update (perhaps with a dash of sound quality boost thrown in), into a very difficult situation.
Balance Between Neutrality and Musicality
UE 900 is not for people who love thumping, rounded bass. You're also not going to get the explosive sparks from each hit of the cymbal. The bass presentation of UE 900 wasn't surprising to me, because it reminded me of the UE-10 Pro. It was deep and accurate, without a mid-bass hump. However, the bass has a slightly warmer sound as compared with UE-10 Pro, and also a more liquid-like texture without being muddy. The bass extension is deeper than even UE-10 Pro while retaining the same ability to resolve texture.
The trebles are very controlled, and depending on one's need for more forward presentation of the high ends, this could be seen as a weakness. Personally, as my ears has always been particularly sensitive to sibilance, I found this aspect of the UE 900 extremely surprising and satisfying. Even though the trebles aren't as forward, they are clearly and accurately presented, but it is going to take a little bit more effort to identify them as compared to any other UE headphone I've ever heard. What was really shocking, is the sibilance control on the treble is even better than on my Sensaphonics 2X-S, which is notoriously less aggressive with its treble than UE headphones of its time.
Detail resolution continues to be a strength through the mids. To the point where I found new, unheard-of-before background sound to some of my favorite tracks. A few of them were the "pre-recording extra sound from the background", a few of them were additional sound in middle of the song that I've never noticed. Not that all of these sounds were consequential the final music production, but it's neat to have those things resolved anyway.
Perhaps due to its neutral presentation, I don't feel as much of a sense of space in the soundstage. Although it should still be perfectly adequate for most people.
Overall, UE 900 struck an amazing balance of getting a neutral sound without being completely analytical. It is by far the most balanced universal IEM I've heard.
Ergonomics & Design
It's pretty amazing that UE managed to cram four drivers into this tiny little package. The size of UE 900 is just slightly bigger than SE535, but it could still pose a problem for people with small ears. Turns out, even with my fairly large ear, the back of the casing could still bump up against the back of my ear and cause some irritation over time. It's not a big deal for me, but people who have small ears should be aware. The good news is UE 900 included five sizes of silicone sleeves and three sizes of comply sleeves. So finding a fit for your ear canal, at least, should not be a problem at all. My right and left ear canal is just ever-so-slightly different size that usually isn't covered by most universal IEM's size availability, but I was able to find the 2 different size sleeves that works for my ears from the finer gradation of sizing that UE 900 offered.
I don't really get why both Shure and UE switched to the "swivel-able" cable plugs. It makes the initial discovery of finding the right angle for the cable to loop around the top of the ear a little bit harder. I'm used to looping the cable over my ears before inserting the IEM, with these swivel cables you're probably better off the other way around. Just put the IEM first and then loop the cable around your ear. The cable is twisted to prevent tangling, and the memory wire section is integrated into the cable with a sleeve.
Lastly, for those of us who has iPhone/iPods, the integrated remote/mic has one of the best "feel" to the button I've ever seen from a third party. The recessed groove in the middle button makes it easy to locate, and the "clicking" action felt just right. It's even better than the remotes made by Apple.
Taking a phone call on the UE 900 was a rather weird experience. I don't know if it's because UE 900 exposes the horrible low bandwidth cell phone sound quality that we're all subject to, or if it's just a particular frequency that doesn't play back well. Most phone conversation I've had on UE 900 was horrible. It's like I'm fully aware of every single sound drop-out, I hear background noises that I normally don't hear, I have problem making out some of the words the others side is saying. Changing back to the cheap Apple earbuds made for a better phone call experience. It was... very strange.
I wouldn't recommend these as a go-to earphone for making day to day phone calls. It's strictly for music listening and having to answer phone calls on in a pinch.
But... I'm a horrible audiophile...
I have to be honest, part of the reason why I wanted the UE 900, is that it's one of the few high-end IEM that comes with a integrated iPhone remote. Hey, quad driver, iPhone remote, what can go wrong, right? What I found is an amazingly neutral, balanced IEM that could be considered one of the best universal IEM ever made. It's available at reasonable price range, which given its universal nature, will eventually see that MSRP come down over time (you almost never see custom IEMs reduce price to any degree, even years after its release).
Technically it's superior to my Sensaphonics ($750), UE5c (discontinued, but UE5-Pro is $600), and possibly even the UE-10 Pro (discontinued, but I guess either UE-7 Pro or UE-Reference is the closest analog now). So if you look at all of those factors combined, it's an extremely compelling product.
But... (there's always a but, eh?) I don't like the UE 900 that much.
Intellectually, I know why I should like it, and if I was asked for a recommendation for an universal IEM, I would definitely recommend UE 900.
However, after listening to hours and hours of music, I realized that my mind was always drifting away when I'm listening to UE 900. I start off focused on the music, but every single time my attention shifts away to some other task after a few minutes. Two hours later, my playlist was still going, and I realized I haven't been "listening" for the past hour and fifty minutes. I was just never able to sink into the music and make that emotional connection that I get when I listen with Sensaphonics 2X-S.
I preferred the muddier & warmer bass of the 2X-S, I liked the less defined vocals and more sticky sound. It's stupid, it's borderline crazy, it's as if a supermodel is in love with me and I'd rather date the girl next door. How long before I just give in and order myself a set of Bose QuiteComfort?~!!!!
So at the end of the day, my personal preference, from a totally subjective and non-scientific and horrible way, is to stick with my Sensaphonics. However that should not detract from the original point that I made, at the very, very beginning of the review: UE 900 is absolutely amazing. If you were looking for an universal IEM, you should definitely give UE 900 a try.
As for me... time to order myself some Bose!... *sigh*