The LAB1s.

The UERM was the first custom IEM I've purchased.  I've had the UERM for almost a month now and I like them very much, but it took a while to even start to like them.  I was feeling a mixture of impressed/not impressed for the first week I had them.  Getting them in the ears wasn't really a pain, it just felt awkward for the first week.  Now I can get them in very easily.  I like how both the HD800 and UERM get out of the way easily.  The HD800 doesn't touch the ear and you feel so free.  The UERM melts into your ear and it becomes part of it, doesn't feel unnatural at all anymore.  The problem I had with the UERM was that it was extremely fatiguing during the first week when I ran it stock.  Even the stock HD800 wasn't as fatiguing to me.  I could barely make it past 20 minutes on the UERM before feeling the need to take them out.  It didn't help that a lot of my music is pop.  I could do 40-50 minutes on the stock HD800 before feeling the fatigue if I remember correctly.  It could also be that I'm so used to the modded/EQ'd HD800 that the brightness of the stock UERM really caught me off guard, or that being so close to the ear drum the fatigue happens faster. 

Anyway, I went on to add EQ starting the 2nd week and it was much better.  First I did a sinewave sweep and it looks like the treble extension hits 16.3k for me on the UERM and drops off significantly.  I could hear up to 17.5k on the HD800 before significant drop off(or the limit of my hearing lol).   I think there was some channel imbalance on the UERM around 10Khz.  Approaching 10k, the left channel sounded a little louder.  Passing 10k the right channel sounded a little louder for a little bit.  Fortunately, I don't notice it when actually listening to music.  The bass goes down to 30hz before dropping off significantly.  Eventually I settled down for a +2dB BW1.0 at 30 kHz, -1dB BW0.1 at 6.57kHz, a -2dB BW0.2 at 7.83kHz, and a -1dB BW0.2 at 10kHz on Electri-Q.

The spatial characteristics are astounding for an IEM.  The UERM sounds eerily like the HD800 in that regard.  I think the UERM and HD800 are the only headphones/IEMs I've heard that gives a "soft" soundstage border.  I'm not sure I'm describing it right but what I mean is that with other phones, the soundstage hits almost a wall and stops abruptly.  For the UERM/HD800, the soundstage border is soft and blends right into the environment.  I know I'm nit-picky about this, but this problem is especially bad on headphones/IEMs with smaller soundstages and it irritates me.  Of course, the only thing worse is heavy coloration.  With that said, I don't think I'll ever be able to pick up a closed headphone again and listen to it without getting annoyed.  The LCD2.2 I had wasn't much better even though it was "open".  It also sounded congested at the same time       

The UERM is very flat with a slight bright tilt, hence its name.  This also makes it a little more analytical though...even more so than the HD800.       

I unexpectedly received my UERMs today (was expecting them on Friday or sometime next week).

Have got a perfect fit & seal.

Very brief initial comments/impressions:

My UERMs do not sound like the perfect-fitting loaner (universal version) james444 sent me a couple of months ago; my pair has less hot treble—in fact, not hot at all—, with better tonality, and more pronounced bass; and the midrange isn't as dry-sounding.

When I had James' set, I remarked that I found it very difficult to spend more than just a few minutes with them—even though I liked them enough to order a pair—as the FAD LAB I I'd recently acquired demanded all my attention. A very short side-by-side comparison now reveals that the midrange and treble are closer (but not the same) in my UERM & LAB I than in James' UERM universal & the LAB I. My UERMs have more bass quantity (though not sure yet they actually have more low-end extension) than the LABs, but the former certainly does not sound wrong, and does not seem to affect the midrange; the low-end on my UERMs sounds more authoritative than the LAB's, but the LAB's midrange remains a step ahead, more resolving and with ever so slightly better tonality/timbre to these ears, more so, in fact, than any phone I've heard to date (but then again, I'm self-declared mids-head).

I also remarked that, on the whole, I preferred the ER4S over (James') UERM. Haven't compared my own UERMs to the Etys yet, but I don't think that is the case now.

My UERMs also seem more cohesive than James' pair (from memory, obviously), but the LAB I, a dual-BA phone, still has more natural transitions between all freqs than my UERMs.

All that said, I've no idea whether James' (universal) UERM is closer to UE's target for these phones—James claims the full custom version he has sounds pretty much the same—or my own UERMs are closer, or whether UE, at some point, decided to alter the tuning. What I do know is that my UERM is a seriously good-sounding phone, one of the very, very best phones I've heard — absolutely no regrets on this purchase.

Dear Musical Sparrow, when you just keep doing what you do best by telling us how some IEMs are worth the cash based on aspect A, B, C etcetera you do not need more karma. You might receive more because your knowledge and experience are appreciated.

Besides that, sometimes your way of saying things is good for a chuckle. Chuckles make life in general more pleasant. Thus for the chuckle you already provided my plus 1 karma has been added.

P.S.

I also happen to like sparrows as they are lively little birds that make waiting on certain Dutch train stations more amusing. Sparrows are cool.

Dude, that link auto-launched at high volume, and overrode a bunch of audio settings on my work computer in the process.

Not cool.