EDIT: Reported to be deleted. Initial impressions copied to main Celestee thread.
Just got the Celestee in and have been listening for about 30 minutes through PC --> iFi micro iDSD BL --> Jotunheim 2 (SE out). Unfortunately, I don't have a balanced cable in for them yet, nor am I able to use my main system as I am confined to one room of my house because of COVID.
First impressions they're very "clean" sounding: almost like a closed, super-HD600 with more detail and better bass extension. Tonally, they're slightly more metallic than the HD600... What else would you expect from Focal?
Those hoping for a warm sound will probably be disappointed but they have a much better tonal balance than the Radiance, which could sound very unnatural with some music. My reference for neutral are the Sundara and Utopia and I would classify the Celestee as a neutral headphone.
The upper midrange hole of the Elegia has been fixed.
There seems to be a fairly wide dip in the lower midrange, which helps give a sense of clarity, but at the expense that it sounds less "full" (cooler) than the HD600, Sundara, and Utopia that I mentioned before.
In "The Peppery Man" by Natalie Merchant, the low, male voices are there, but lack the depth and weight that I have come to expect from a neutral headphone.
The dip in the lower midrange helps keep the bass from interfering with the midrange, but it goes a little far and can make the bass sound slightly detached.
The closest frequency response I've heard from a closed back would be the (then) MrSpeakers Aeon Closed (original) but the Celestee is a step up in nearly every regard.
The bass is missing the slam that Focal is so good at with their open-backs. They come across as a bit flat sounding.
Imaging is good but the soundstage is wider than it is deep.
More listening to come and hopefully with better gear.
How do you like the pairing with the Ifi micro BL? I have the ifi Zen Can and find that the 3D button opens up the stage nicely for older recordings. I was thinking about getting the BL/Signature for portable use.