When Ultimate Ears' Paul Manfrini called me to ask if I wanted to participate in the beta testing/evaluation of what would be their new flagship custom IEM (in-ear monitor), I said what just about any other Head-Fi'er would say: Yes. My first custom IEM was Ultimate Ears' UE 10 Pro, for which I was fitted and placed my order at the first-ever International Head-Fi Meet in New York in 2006. Later, I was a beta tester for both the UE 11 Pro and UE 4 Pro. Ultimate Ears' top models are among the best headphones I've ever heard, the UE 10 Pro still being one of my standards for neutrality, and the UE 11 Pro being a bass-enhanced (yet revealing) fun romp of an IEM (and a favorite of many top stage performers). Asking me to beta test (especially a new flagship) isn't something they have to do twice.
Codenamed the UE Z, the prototype I've been listening to is built to what ended up being production sonic specs, which is a very good thing, because the UE Z I've been listening to has deep, mildly emphasized low midbass (I'm estimating the mild bump to be centered around 50 Hz); rich, forward midrange; and a very nice, very extended treble. Equipped with six drivers per side, the UE Z is a true four-way design. It also comes with what I think is the nicest stock IEM cable currently available.
The UEZ sounds to me like a sort of UE 11 Pro Mark III (no, there was no Mark II, but the UE 18 Pro is improvement enough to feel like a couple of good steps ahead of the UE 11 Pro). Compared to the UE11 Pro, the UE Z has firmer, less emphasized bass (though still north of neutral down there to a degree I think will find great favor with many a Head-Fi'er). The mids are not just more present, but also more liquidy, more lush than the UE 10 Pro and UE 11 pro. And the UE Z's treble has detail and sparkle that trumps anything I've heretofore heard from Ultimate Ears--I love its treble as much or more than anything else about the UE Z.
Oh, but let me stop calling it the UE Z, and cut short my impressions for now, as, in less than an hour, the UE Z is going to be officially announced by Ultimate Ears as the UE 18 Pro. Whereas the UE 11 Pro didn't necessarily inherit the mantle of Ultimate Ears' flagship from the UE 10 Pro (opinions were split, even mine waffling between the two), the UE 18 Pro is, to these ears, clearly the new flagship UE. From the start, I got the impression from the team I've been talking to about the UE 18 Pro that the primary target customer was the professional stage performer set, but with some hope it would also find favor with the audiophile types--mission accomplished, I say.
Here are some photos of the prototype Ultimate Ears UE 18 Pro I have (click on the photos for larger versions):
When Ultimate Ears officially announces the UE18 Pro, the product URL for it at their site will be Utimate Ears Custom UE 18 Pro Description - Custom Store - Ultimate Ears Earphones Headphones Personal Monitors