You’re certainly entitled to your opinion!
Some timeline info for you Will: Axel is of course a bit of a perfectionist; he had prototype V5 at CanJam NYC just a month later after CES, and he said he had another prototype back at headquarters that was even closer to what he was targeting. He certainly did make several revisions between CES and release, before he stepped down from Chief Engineer in January 2019 and became “just” a consultant.
When talking to him at CanJam NYC 2018, he said one of his goals with the revisions was to move that small dip up higher in frequency (I think 80 or 100 Hz was his goal, my memory isn’t completely exact on that), because a little dip right there in a closed headphone helps prevent some of the apparent bass bloat and muddiness. You can see that, overall, the HD 820 has more bass than the HD 800 S... some people really wanted that, some people don’t realize the HD 800 and HD 800 S actually has more bass extension than the HD 6XX (and the large ring driver gives it a really tactile feel with both the HD 820 and HD 800 S). I admit I don’t have insight into the dip centered around 290 Hz... other than how reviewers often cite that range as contributing to a “cuppy” or muddy sound as well, though on the other hand too much of a dip at that range can lead to a feeling of “hollow” or “disattached” bass. The final judge should always be listening for yourself!
Personally, when I tried on the headphone, I was kind of “meh” when the prototype headphone was placed with the driver centered over my ear canal. It was indeed spacious, and isolating well, but when I moved the earcups down and a bit forward on my head, I got a fuller bass experience which I found very satisfying, and more natural compared to a Sony Z1R and Denon D5000 that I had side by side with it. That’s just personal anecdote and preference, but my “trick” has pleased me with subsequent listens at future CanJams (it has been a few months since I heard it last).
I have not heard Drop’s Ether CX, because I haven’t seen Drop at the shows I attend (and sadly I can’t buy everything I want, problem for everyone right??). When I heard the original Ether C, I easily preferred the open Ether. I could see some people preferring the Ether C(X) though. One objective thing I would like to ask if you have the data: is the Ether CX fully sealed, or is it a vented design?
I share your adoration for Zack’s headphones, also quite chuffed when I get a chance to spend time with the man himself, but my knowledge of his latest closed headphones is also out of date (there’s that money problem again!). I remember the Ori was vented, so while it still had some isolation, it didn’t block leakage or environmental noise as much as the HD 820 would, which may not be important to some or crucial for others.
The DT1770 (or DT177X Go) might be a viable option for our original poster due to it being within his budget, and due to being a sealed/closed headphone. However, it does NOT have close to the soundstage size and “open sound” of the HD 820. The DT 1xxx series made great strides in addressing my main issue with the “classic” DT xx0 headphones: the treble spike that aggravated *my* ears and left them ringing. Other people who don’t wear small IEM tips might not have the same issue as me. It is fairly well detailed, so a surround DSP may help with the “in your head” small soundstage, but they only perform small miracles 😉
The HD 820 might be big, or even overkill for studio monitoring use while recording a track, but it could do it. For me, it just won my top spot because it was the “no compromises” option, and I happened to like the sound a lot (when placed a little off center). I tried to state the objective alongside my opinion, because of course my opinion is subject to change with experience 😉 I hope to get a little more during CanJam NYC this weekend!