As promised here begins a comparison between the UERM and the ER4S.
I should say that I heard the UERM last summer at the LA meet, and I wasn't impressed. I found it somehow both boring and confusing. The soundstage seemed to have gaps, as though there was a disconnect between the drivers. Treble was recessed, or so I thought at the time, which I now attribute to using comply tips. These tips might have also resulted an uneven fit. So I wrote them off.
James444 and Eke were nice enough to organize a tour of the UERM (and another iem that won't be the focus of this review). The UERM on tour is the universal version, so there should be some minor differences between it and the custom version. I've gotten a very good although tight fit with the UERM. The body of the universal is very big, bigger than the ASG-2 and W4.
I've had the ER4S for about 10 months, and in that time it has become my favorite iem (as anyone keeping up with this thread will know). I find it to offer the most realistic reproduction of music I've heard in an iem, and my experience with quite a few other iems has left me with a rather skeptical view of most gear out there. I tend not to buy things unless they graph a certain way, or look really really pretty like the ASG-2. So when I first put the UERM in my ears, it was with the same skepticism I aim towards everything. I opened the package in my car in the post office parking lot, and plugged the UERM into my Fuze for a quick listen.
First I looked for a flaw. I already knew what the graph looked like, so I had an idea of what to look for. First song was The Last Resort by the Eagles from their Hell Freezes Over tour. I expected to hear a big ugly mountain of a treble peak towering over a deep barren valley of mids. But it was not to be. Henley's vocals were clear, some of the clearest I've heard. And the treble was no mountain. It was a small hill. Wow. I listened for 30 seconds before taking them out and driving home.
Let's get more specific. First up: bass. The UERM has more bass than the ER4S with red filters. It extends deeper by a few Hz, but it isn't quite as tight as the ER4S, a trade-off for the slight emphasis. Compared to any other non-etymotic iem though, the UERM has some of the tightest bass I've heard. And the mid-bass! It really leaves the mids alone, although the mids are still not as crystal clear as the ER4S. Why is this? I'll tell you it's not because of any mid-bass bloat. There is none. No, the UERM has a dip at ~2.8kHz that warms the mids up ever so slightly. Many iems I've heard (IE800, W4, etc...) have a dip at 3kHz, but they also have some level of bass flabbiness that creeps up on the tasty mids, making them all flabby too. The UERM can get away with this dip for two reasons: 1) it is a small dip, only a few dB, and it isn't very wide, and 2) there is no mid-bass bloat further warming up the poor mids.
The mids of the ER4S and UERM both sound great, but the ER4S pushes out that last bit of clarity missing in the UERM. Etys usually have more forward mids, and that's the case here. Without a more linear response at 3k, the UERM mids sound a little fuzzy in comparison. Fortunately a 3dB bump at 2.8k brings the UERM mids in line with the ER4S. With this bump, I hear the mids on both iems as extremely similar, except for one thing: sibilance. No, neither iem has it, but the UERM is closer to exposing it on a sibilance riddled track. It just isn't as smooth as the ER4S in the upper-mid and treble department. Let's talk about that.
Treble. This is where these two iems differ the most imo. We all know the ER4S for it's smooth, well extended treble. It's doesn't have any major problematic peaks, which gives it a transparency that is hard to touch in the iem world. So how close does the UERM come? Well, it's got a 10k peak. And a small 7.5k peak to my ears, followed by a small dip. Usually this is bad thing imo. It emphasizes the sharper, more abrasive aspects of percussion and vocals that take away from transparency. But I don't think this has happened here, at least not to an offensive degree. The UERM's treble, while clearly more emphasized than the ER4S, doesn't take it to the insane degree of the SUI or IE800. It's a more reserved emphasis, that can even improve clarity in some respects, while sounding just a bit tizzy with hotter recordings. To me, this puts it behind the ER4S in treble reproduction. It's still top notch treble, some of the best I've heard, but not as good as Ety treble.
The presentation of the UERM is a little bigger than the ER4S, which is really just my personal perception based on the FR. The UERM is a bit more v-shaped, so the sound is just a little more spread out than on the Ety. This trick usually comes at the expense of detail imo, which can be seen in the less tight bass and somewhat fuzzier mids of the UERM. There are always trade-offs.
Overall I'm very pleased with the UERM, although I'd change a few minor things, like the 3k dip and slightly uneven treble. But there are also things I'd change with the ER4S, like increased bass at 50Hz and small increase at 7kHz. These are two very good iems, and I think the UERM would make most ER4S fans pretty happy.