One more thing, I think that might be helpful to others, according to ZMFs own guide that comes with the Atrium, the universe pads are the closest tuned to ZMFās āhouse soundā, while they rec. the Caldera Ultra Perf. pads for slightly brighter tuning (what im using currently), and Auteur Perf. pads for a warmer leaning sound. Iāll have the universe pads by wed according to tracking, and I just ordered a pair of Auteur pads to try out as well. If youāre okay with the driver pressing your ear lobes a bit, the BE2 Suedes do sound pretty good for a warmer leaning sound, but I personally hate the feeling, so I wonāt use them on these, regardless of tonal qualities.
You can also try out a solid titan mesh if you need to cut down on the treble a bit 2k and above, but even with the Caldera Perf, itās tuned really well. It gets a bit bright with some āpopā music by just a hair, but it sounds amazing with acoustics. Looking forward to trying out the universe pads, seems like they might hit the sweet spot.
i tried the Be2 Suede pads and hated themā¦robbed all the bass impact. DMSās preferences are clearly are way off mine.
The universals were good but i settled on the Auteur padsā¦just hit all the right spots for me.
Nice, I can see myself liking the Auteur pads the most as well.
Just for the record the BE2 Suede pads sounded the best to me, and delivered on the āupgrade to the HD650ā promise in a way the other pads I tried (universe and auteur) didnāt
Iāve been giving the BE2s a second chance have been listened to them for several hours last night and this morning and they do deliver on upgrade 650 for me as well. I agree with that. I guess the question for anyone getting these is, āIs upgraded 650ā what you want". I think for me, sometimes, if I want a laid-back sound, but I also agree a bit with Dave and that they rob them a bit of their dynamic capabilities (punch and slam, decay due to the suede absorbing the sound a bit). Iām personally looking forward to trying them with the Universe pads, but with the solid titan mesh to reduce the ear-gain a bit. I think no matter what you put on them, they sound really high performing. Iām starting to really get the tuning-system they are going for too, given how much the tuning changes with just a pad change.
Zeos tried them with the Brainwave pads saying these were the best but when i tried them they turn them into total bass cannonsā¦i do wonder about some of these reviewers ears 
I have a feeling his colab headphone is going to be insane. lmao
Update 3: I got the Universe Hybrid pads, and I think they are a very good choice as well. They have a similar effect of taming the treble a bit like the Auteur hybrids, but you get the slightly wider sound stage.
Update2: Iām finding I prefer the leather universe pads at lower (more reasonable) listening volumes (60-70db). Music maintains the lively dynamic punch. Perhaps this is the intended design with the stock pads. This also occurred to me because someone brought up the āfletcher munson curveā aka humanās having different perceptions of bass and treble at different listening volumes. Iām used to listening at higher listening volumes to get that dynamic feel from something like the Clears. Not fatiguing at all at more reasonable volumes. Better for long-term listening health as well. 
Update: auteur HYBRIDs are king! The hybrid pads tame the treble just enough to put them below the fatiguing threshold for me, while maintaining the airy detail I really like from the stock filter. Decided to give them a go after seeing passion for sound recommendation of them. Going to give the hybrid universe a try as well. But Iāve been listening to them all weekend with this setup and they are godlike.
Original Post:
I tried a handful of pads and also got the solid titan mesh. Solid mesh with Universe Leather perf is my primary preference with these. The stock mesh definitely gives a little bit of that extra āzingā and detail you kind of expect from $2500 headphones, but itās a tad fatiguing honestly. Also really like the extra ābodyā you get in the low end with the universe pads compared to the ultra perf caldera pads. I can see myself being tempted to go back to the stock mesh at some point when the mood strikes tho.
Nice, I ordered mine with the Uni Hybrids if I remember correctly. I will have to give the auteur hybrids a try when I get the chance. First things first, I have to get my Atrium in hand and try the pads i ordered. My Mjolnir 3 and Bifrost 2/64 are warmed up and ready to go once they arrive. 
Trying to pick a wood headphone stand for when my Atrium gets here. Looking at this one right now, but I am not set on the wood combo yet. https://www.etsy.com/listing/1556372169/curly-bubinga-and-black-hornbeam?click_key=a27091087388f2adcec593740ccc6ea0859b321b%3A1556372169&click_sum=7f014cae&ref=shop_home_active_6&frs=1&sca=1
Or these ?
Finally got another update after 3 weeks. My Atrium is heading to sanding. Hopefully I will get a shipping notice sometime next month. Someone in an other forum got an email saying that there was an imperfection in the wood cups and they offered him the option of reducing the cost to B-stock or making a new headphone. He chose for them to remake it, but in my case I would take the reduced price and buy some more pads and/or a nice cable.
Cable I ordered on EBay finally came in. Feels so much better. Way more light weight and super flexible. Love these types of cables. Practically feels wireless (except for the wire, lol). In terms of weight, at least. Drapes really nicely.
The Vali 3 thread on head-fi is tempting me to pick up a unit with my Yggdrasil next year (provided that Valhalla 3 is still delayed). It would be fun trying the Atrium paired with that combo.
Looks like it might be a fun little amp!
I think I got used to the treble with the stock leather universe pads, because the auteur pads sound a bit too dark in most circumstances to me now. Lol
Also as a general update, still loving these headphones.
I should also mention that the Audeze LCD Boom mic cable work great for gaming with these on the PS5 with a Schiit fulla or hel. I had ordered them initially with the ZMF gaming boom mic cable, but I got complaints of echo with those, I donāt think those do enough good noise canceling. Audeze boom mic, I was told no echo even at higher volumes, works great.
A lot of comments discussing a possible 3khz peak with new Atrium Open over on HF. Some say it comes down to pad + mesh choice, and burn in time. I am really curious as to wether or not I will notice it when my AO arrives. 
Well speak of the devil. I just got my shipping confirmation from ZMF a few minutes ago. 
Iāve never noticed a 3k spike except for when I was using a D90 with a singxer SA1. After I swapped the DAC things sounded way more natural.
And congratulations!!!