I had a UE700 reshelled, with an added bass driver. I wanted to contribute some impressions because I haven't read any yet. Maybe it's not common to reshell the UE700? Anyway:
Originally, the IEM was known to have a really good portrayal of soundstage depth, as well as a focus on upper mids and having extended treble while maintaining good detail. The main criticisms against it were that the treble could be "hot" and shrill, oftentimes turning siblant. It also tended to be relatively bass light. My story with the UE700s were that I liked their sound, although I hated the build quality and the cable. I eventually decided to have them reshelled after the cables turned so hard that they started to curl up on their own and pop out of my ears during normal listening. During the turnover process I asked UM to do something about the treble, which was even brighter (albeit with lesser detail and extension) than my HE-6. The local UM rep told me that UM doesn't really do custom tuning anymore unlike in the past, but he'll try. I don't know if the request got through.
UM added a Knowles CI22955 for the bass, and kept the (way too popular) Knowles TWFK for the mids and highs.
Top to bottom: UE700x3, UM Mage, Original UE700
To describe the sound now, the UM UE700x3 in my opinion is mid centric, with accurate bass response and relaxed treble. Think of the treble as something similar to the HD650 (in terms of soundsig and frequency response, not detail retrieval) On some tracks it can tend towards the warm side, with an emphasis on the lower mids. In other words, there's a huge difference post-reshell, and it sounds like a typical UM custom now. I've auditioned the Aero, Merlin and Miracle. I'll discuss what I didn't like so much first:
First of all, I wasn't expecting something that sounded like a stage monitor to come back, since I liked the sound of the original UE700. I thought the original sound signature would be maintained, with a bass boost from the extra driver. Luckily, it turned out alright because they sound great. Next, for some reason the UE700x3 can sound a bit muddled in fast tracks, which never happened before when it was brighter. It doesn't happen with the Westone 4 or the SM3, so I'm left wondering why as the bass response is quick and accurate. Unfortunately, my guess is because the treble response was lowered too much in order to be in line with the UM sound signature. It's something I'm willing to live with though since the accurate soundstge (which was the most important thing) is still there. The original UE700 also seemed to be more detailed, although that might be misconception because of the warmer tone.
What I liked about the UE700x3 is the suddenly impactful and punchy bass which I'd never have dreamed of given how it sounded in the past, as well as how smooth vocals sound on them now. Given the frequency response charts, I wouldn't be surprised if they now sound quite similar to the more expensive UM Mage (I bought the UE700 for around $100). The impressions I've been reading about the Mage on the review threads pretty much say the same thing as my earlier descriptions. In conclusion, the only I can advice is that if you're adding drivers to your IEM during the reshell, don't expect the same sound. In fact, expect a drastic change in sound. It can turn out for the better (or worse), depending on the listener.
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). Now I sort of wish I went the UE700 reshell route. Although at the end of the day buying a mage is probably faster/safer (though UM will test the drivers you supply and offer to replace them if they're faulty, or replace them for free), so I don't really mind.
