Got my Ether-C in the old box! First impressions... build quality is great, as I expected given my experience with the Ether. Weight is a little more, obviously because of the cup, but still way less than my other headphones. After a few hours listening happily at work I took it home and conducted some quick-and-dirty shootouts using a number of reference tracks...
1. Ether-C vs Alpha Prime: (Both using Norne Zoetic cables). I am on record as loving the Alpha Prime. It's a neutral-ish headphone with great dynamics that's fun to listen to. However, it lacks a little bit of detail and is a fussy fit; it has to be rotated just right to get it to clamp evenly (and no, bending the headband never did help). Well, the Ether-C also has those sonic advantages but is noticeably more clear and detailed. Fit is perfect, basically just drop it on your head, adjust the slider (once), and it becomes invisible. Definitely a win for the Ether-C, but not a big win.
2. Ether-C vs LCD-XC: (Ether-C using Norne Zoetic, the LCD-XC using Norne Vanquish.) Yeah, the LCD-XC has issues with weight but with the suspension mod I find it not to be a big issue. Sonically the LCD-XC is extremely detailed and a bit treble-heavy. It's an outstanding headphone but I can't really call it "fun", at least for my tastes, since it can be a bit antiseptic and fatiguing. With the Ether-C, you also get great detail but without any grainy character, and a more realistic tonal balance that's less trebley. Unless your tastes run towards the HD800 end of the spectrum, I believe the Ether-C is the solid winner here. (It still remains a puzzle to me why Audeze chose to make the X family sound so different from the 2/3... yeah, variety is great, but at least advertise the sonic differences so people can make an informed choice without having to browse forum threads.)
3. Ether-C vs Ether: (Both using Norne Zoetic cables). Ahh, sibling rivalry. Very similar sonically, except that while the Ether-C is extremely clear and intimate, the Ether takes that even a step further into the realm of the absolutely ******* insane. There is no non-electrostatic headphone in the world that provides as crystalline and transparent an experience as the Ether, it really does sound like it's wired into your brain. (And I'm about ready to admit it may even match the Stax SR-009 in that regard.) So I'd give the nod to the Ether. However, we are talking apples and oranges since the Ether is open. To me, the Ether-C is indeed the best closed headphone in the world.