Nope, I've always said the K712 is slightly darker/warmer.
Just making sure I did not need to clear something up. I am always up for open discussion after all I am still learning too.
For those of you out there with the HD800 wanting to try the AKG K712 Pro I say forget it. The HD800 is just about the best headphone out there and is clearly more engaging than the AKG K712 Pro.
Sometimes specific instruments can be more airy on a specific headphone and the midrange can remain quite intimate, but I agree that if the entire FR is airy then one would expect it to be less intimate. The terms are not exactly antonyms, but I see what both of you may be saying.
When I say "air" I'm mainly talking about the treble and reproduction of high frequencies.
When I say something is airy it means that the high frequencies are present and you can hear the low level high-frequency detail and ambience from the recording space. A less airy sound is where the highs are darker and more rolled off with a blacker background.
I don't conflate air with how open a headphone's soundstage is though. Take the AD900 and the MA900 for example. Both have big open soundstages, but one reproduces more high frequency air and the other rolls off the highs a little. A headphone can be darker sounding but still have an open soundstage. Likewise, a headphone can be intimate sounding but still have good reproduction of air from the recording.
Here's what's in the "Head-fi Glossary". As you can see it mentions both the soundstage and the high frequencies:
Airy - Spacious. Open. Instruments sound like they are surrounded by a large reflective space full of air. Good reproduction of high frequency reflections. High frequency response extends to 15 or 20 kHz.
Personally I would separate that definition into two separate things, because it's possible to have one (spacious/open) without the other (good reproduction of high frequencies). A headphone can be more spacious while also being darker sounding. That's the case with the K712.
So for the Anniversary and K712, the Anniversary has a slightly more airy signature with more forward upper mids and slightly more treble presence, while the K712 is slightly darker and more rolled off with a blacker background. In terms of soundstage though, the K712 is slightly more open sounding, less intimate, and with slightly more space - EVEN THOUGH it is slightly darker sounding.
Thanks for the comment... Actually, I was thinking about trying those K712 Pro and eventually sell HD800 to save some money (I am quite a pragmatic person sometimes). But yeah, my friend had K702 65th anniversary and told me that they are very nice and quite balanced but cannot substitute HD800 fully. Unfortunately...