What is it about them that makes them your favourite? What gear do you run them on?
First, they're comfortable. Not actually a perfect fit, although the original pads are pretty good. And they're not light enough to my taste. But they're still pretty comfortable. The headband does a good job spreading the weight out, and the materials are good quality. I generally don't even get "sweaty ears", even listening to them all day.
Second, listening to them for long periods of time doesn't drain me. Some headphones leave me feeling worn out a bit, due to some combination of the physical aspects and the audio aspects.
Third, for a closed back (which I often need in the office because co-workers), the audio is very good, at almost every volume. I often listen at super low volume levels, like "most people couldn't even hear the music" levels, because my hearing is important to me. And they still deliver lots of information (clarity, all the instruments are there, voices are good, etc.), at super low volume levels. I'll turn up the volume sometimes to enjoy a particular song, or drown out someone else's zoom call, or whatever, and they sound great. My hearing is still very good, but I know I'm starting to lose a tiny bit of sensitivity now (in my 50s) and I no longer hear the 20khz stuff, which apparently goes away sometime around 40 years old for most people.
My office setup: I use all FLACs via Audirvana on a Mac out through a ladder DAC from Denafrips (Ares II or Pontus II or something like that ...
not the Terminator or whatever it's called) amped via a Woo Audio WA5-LE with balanced output. That setup makes a lot of headphones sound great, though, so it's kind of cheating. When I'm alone in the office, I'll use P1000 open back Grados sometimes, which are magnificent, but obviously quite a different approach to headphone design. Occasionally, I'll use my JH Laylas (balanced custom fit IEMs) with this setup, but they're just too much work to get on and off in a hurry when someone needs to ask me a question or I get a call.
I have other headphones (Audeze, Sennheisers, Focals, Grados, Beyerdynamics, etc.), and I have used them with this setup, and they mostly sound very good, but once I got the Ether C, I just stopped looking for anything else, and the other headphones migrated to other places and uses. The Ether C was exactly what I had been looking for
Coincidentally: An audiophile friend of mine here who had originally gotten me to check out Grados about 20 years back (I still have and use my original 225s) had settled on the Utopias as his "end game", but somehow he also found the Ether C, loved it and picked one up (not even knowing I was using the same). Ultimately he got rid of the Utopias and kept the Ether C. He came to tell me about his new find, only to find out that we had both independently come to the same conclusion.
I have no doubt that Dan Clark (and others) have produced even more amazing stuff over the years since, but I'm honestly happy with exactly what I have. I'm still glad to try new stuff out, and I'm always happy to check out good closed headphones, and occasionally I do buy new kit, but for listening to music in the office, the Ether C is still almost perfect, and definitely is still unbeaten (for me).
