Since there aren't many of us out there yet who actually have a Merlin to listen to, I feel that I owe you all some more listening impressions. Just to give you the general idea of what the Merlin is like. This is by no means definitive; anyone who knows me or has read my reviews knows that I take ages to listen and be thorough.... this is just general musings.
The setup here is Squeezebox Touch FLAC files -> Anedio D1 DAC -> Violectric V200 amp -> Beat Audio Cronus cable -> UM Merlin. Remember that my Merlin is a prototype that has somewhat less bass under 200Hz than the final edition will.
So far, the Merlin is living up to all of my expectations, with the exception of being a bass monster. It is very clear, very smooth, and has amazing dynamic ability. The biggest surprise for me was the expansiveness of the soundstage; possibly due to the vented design, I really can't say... but this might be the most open sounding IEM I've ever heard. The Miracle was already very good in this regard, but the Merlin is on another level.
Another thing I like is the clean detailed top end, with no trace of harshness or sibilance unless it is there in the track. It makes you want to keep turning the volume up up up, because it is so non fatiguing. At the same time it is NOT recessed at all.... it's actually very clear and crisp, in the tradition of the UM house sound. Despite the draw of the dynamic driver for lows (which is either a gimmick or an innovation depending on your point of view), the mids and highs deserve high praise for their performance. From the look of things the Merlin uses a different array of drivers than the Miracle. I really need to dig out my listening notes from when I had the Miracle, but I'd say tentatively that the Merlin is a little more smooth and organic, and probably a little more forgiving. Miracle is a tiny bit more focused, detailed, and accurate. But of course both have very high levels of all categories. I don't want anyone to take this as me saying the Miracle is not smooth, or that the Merlin is not detailed. They just both have their specialties.
As far as bass: My Merlins have hard hitting bass that seems to be limitless in extension. It is natural and effortless, and actually reminds me a lot of the Miracle (which I LOVED) but with a tad more presence. As much as I enjoy these Merlins as is, I think I see why they decided to tweak it to give more bass. At the moment, this is more of a neutral performance, and is really not extremely different than the Miracle. If they intend to market them as sort of a JH13/JH16 type of duo, then the Merlin NEEDS more bass to correspond with those expectations. The bass on mine is excellent but is not really a defining characteristic. It is less in quantity than my Lawton LA7000 for example, which in itself is already less than the stock D7000 (a good thing in my opinion, but moving more and more away from "basshead" status).
Quick comparisons: last night I had some free time, so I was switching back and forth between some of my newest customs - the 1964-T, the Westone AC2, and the Merlin. The other 2 certainly have their strengths and weaknesses, but overall the Merlin put them both to shame. The 1964-T sounded flat and boring in comparison, even though I normally find it natural, warm, and smooth. Despite using dual BA drivers for lows, it did not have the punch or rumble of the Merlin. I'm sure this is partially by design, since 1964 did not intend for this model to be a bass monster. But still. Highs sounded a little grainy and unrefined compared to the Merlin, and it was not as engaging. The AC2 actually has huge bass (I'll finish my review one of these days) but it isn't as realistic as the Merlin in either impact nor decay. AC2 also sounds harsh and sibilant on some tracks, where the Merlin is smooth as butter.
I know it isn't a fair comparison because the other 2 are around half the price, but those are the ones I've been listening to the most recently so it was a more informed comparison. It also sounds like I dislike the Westone and 1964, but again that is far from true. I'll have to spend a lot more time listening and comparing but those are some quick impressions for now, just to give people an idea.I believe Stephen from custom-iem.com has convinced UM to send me a final model of the Merlin since it was sort of a poor choice on their part to send the prototype, knowing it would be reviewed (and the resulting review would not be helpful for anyone). So hopefully I should have both models here with me at some point in the near future, to compare and comment on. I've decided I'm buying the Merlin over the Miracle (yes it is that good), so it will just be a matter of which Merlin version I like better.
