Above 3khz yeah.
I expect this is most likely just due to seal imperfections. As shown in the driver Fs measurement above, the bass can fall off if you break the coupling with the side of the head. And, breaking a seal is often a matter of degree. So for many who wear glasses for example, if they only get a partial seal, they will lose low frequency presence in situ.
Ok because some other ‘ people ‘ said to give the Noire X some time to ‘ burn in’ and that would change the sound of the drivers.
Quoting Vance Diakansons speaker cookbook.
IMHO has nothing to do with burn in as we think of it for a bright transducer becoming warmer and thicker.
Driver ‘burn in’ is not something anyone needs to worry about.
Nope not at all
In fact as a speaker hobbyist myself I do have the book.
Burn in for drivers is applied to get the T/S parmeters stable as suspension does soften initially. And to make sure nothing is wrong with the driver. This also allows for fine tuning the box and port
I highly doubt this has anything to do with headphone transducers and probably should be taken into account with the design and headphone geometry and enclosure are made.
It would seem odd to me that a manufacturer would make a headphone and not take all these into account.
Although I’m not familiar with the headphone making process.
Also I don’t know how planars behave. I suspect something similar goes on
And here are the excerpts from the book for those interested.
Maybe what is actually happening is the seal is improving as the pads wear in.
That would make far far more sense
It’s not like transducers are shock absorbers.
Lol
Sorry. The whole “ wait till it burns in and then it will go from shrieking bright , to warm and cozy” is just beyond me.
I mean it’s not like everyone is gonna like your product. And for headphones from what I am gathering, is that things differ from our ear anatomy. Up to a point of course
I had a guy once tell me that about a NAIM amp. Cause I didn’t like it. He was like “ it needs to break in”. 
Of course I returned it. Got a Benchmark AHB2 and it did all the NAIM claimed to do. Done with amps
Here is my summary about Noire X vs E3.
So after a weekend of intensive testing between the Noire X and E3 for me the outcome is that I will keep the E3 and will return the Noire X.
It wasn’t so clear to me after listening to the NX for the first time.
The NX (without EQ) plays livelier, has the tighter low bass, but a little less bass and has silkier upper mids than the E3.
The E3 (without EQ) had a bit too much, and therefore less precise low bass and didn’t sound as silky in the upper mids, piano didn’t sparkle as much. Comfort wise, the cups on the NX are quite small (but OK for my small ears) and the contact pressure is higher than on the E3. The spaciousness was something that the E3 was always better at. This impression is maybe caused simply by the larger ear cups of the E3?
With the NX, I had to increase the low bass by 3 dB to make it work for me. If you lower the low bass on the E3 by 3 dB, it also becomes tighter and still fits for me in terms of quantity. If you add some upper mids to the E3 (first test was 3dB at 1.5 kHz), then it also becomes more livelier (voices come more to the front), more silky with the strings and the piano is more sparkling.
So the reasons for me to keep the E3 are the better spaciousness, the more comfortable fit and any tonal differences can be easily counteracted using EQ.
If I had to choose now between a new E3 and the Noire X it might have been a different outcome, the Noire X is damn close and also easy to EQ to taste.
YMMV
Interesting. Sounds like they’re fairly close in terms of performance overall. Does spaciousness for you mean how it sounds or how much space your ears has in the cups?
I was very impressed by the E3 at Canjam, got a set coming soon in a week or so. When I A/B it at Canjam against their set of Aeon RT Closed, I thought the E3 was clearly more detailed at the mid range. However my own set of Aeon RT Closed at home doesn’t have tuning pads. Anyway I guess we’ll find out.
I find that very careful and detailed EQ to level out unevenness in the treble range by L/R channel makes a huge difference. Every set of headphones I’ve ever owned can eventually sound right tonality wise if I could narrow down the exact flaws in the FR. So for me what really matters are stuff like comfort, sound stage, clarity, sub bass performance. Hopefully the E3 is an actual upgrade for me.
Thanks to your review @Daiyama , I’ll skip the Noire X no matter if I end up keeping the E3 or not.
With spaciousness, I mend the sound impression and maybe this perception is due to the more spaciousness of the E3 ear cups. 
Sorry, I am non native English speaker, trying my best (with a little help from DeepL).
For this I use the recordings of the “Pantheon Sessions” where you can hear very good the size of the Pantheon (in Nashville), where it was recorded. Quite bigger with the E3 than the NX.
Nice summary there. I haven’t done the head-to-head face-off, but my first reaction to the Noire X was a little more positive than it was to the E3, for basically the same differences you’re pointing out.
I’m very curious if the Noire X helps the “macrodynamics” problem that the Noire has. Good tuning but sounds rather damped, muted, and lacking aliveness. Can anyone directly compare the two on that dimension?
Only from memory, it is quite some time ago I owned the Noire. But from this I would say the Noire X is definitely more lively and punchier while still having this balanced tuning.
I’ve never heard the (OG) Noire, but assuming it was something of a progression from the Aeon X Closed, and that a comparison to the latter might be helpful, I will say, IMO, there is a profound (like marked, major, massive, big-time) step up in what I’d consider “aliveness” with the Noire X. The Aeon X Closed struck me as muted and lacking “aliveness.” Like it sounded nice, but was a wallflower. (Now maybe that’s because I’m usually listening at low volumes.) The Noire X is a very alive closed-back.
The Focal Azurys is great too, maybe not quite as dynamite as the Noire X, but a lot cheaper. Anyway, between those two, you’ve got great choices.
This was very apparently true to me when I A/B tested the Aeon RT Closed vs the E3 at Canjam. However, the Aeon RT/X closed comes stock with those paper filters. When I listen to my own Aeon RT Closed at home with my custom EQ and without those filters, they never sound to me like they’re muffled or muted. Soon I’ll get my hands on a set of E3 to directly compare at home.
From what everyone’s been saying, the Noire X really doesn’t sound like it’s much of a downgrade from the E3. Some test graphs show it to be maybe very slightly inferior in distortion and it has slightly different tuning than the E3, but overall they seem more similar than not?
Ah, that’s right; the Aeon X Closed also had those felt filters, and I didn’t change them around much and was just going from memory in making the comparison above. Looking at them now, I can see I had the white, one-notch filter in, which you would think could have dampened things a bit, but according to the posted measurements on Drop didn’t do all that much – maybe +1 dB <500Hz, -1dB from 1-6k. Images below:
I also have a gigantic head. May I ask you @Resolve how extended the headband needs to be to get the HD650 to fit you? And did these need any finesse to make them fit?
I’m worried these headphones won’t fit me, because the 650’s headband fully extended is just barely too big for me, and when I had the chance to try Abyss Diana headphones, no way in hell to make those fit me. Too small. The 109 pros fit me perfectly, and that’s all I’ve been able to try.
I mean the HD 6 series clamp is more based around how much the arms are stretched out. So me indicating the clicks is less helpful. I don’t have them all the way out but pretty far.
If you have a large/wide head, the clamp may be too much on the Noire X. If you have a medium sized head it’ll be no problem. But really head width is the issue, not so much head height lol.
See I’m like that but with width/girth.
@Resolve Maybe we need to revive phrenology, but for headphone users…
