What does the audio term 'air' mean?

When can talk about frequencies associated with what many people might call “air” but for me it comes down to a type of perception and not necessarily a particular frequency range.  Because I’ve heard some speakers that don’t go stratospherically high in frequencies, but still have a sense of “ air.”

What that generally means to me is a sense of openness to the sound, generally aided by a type of high frequency character.

So for instance, if I’m listening to recordings on quite a number of systems there’s a distinct difference between the frequencies and the recording, and the frequencies of how things sound in the real world, represented by the room I’m in.

You play a track where somebody is tapping some drum rims or the symbols or clapping.  And then in the same room, I snapped my own fingers or lightly clap my hands.

This reveals a difference, where the  sound coming from the speakers sounds “ canned” or sort of artificially limited in the high frequencies, which distinguishes the sound from a “ live happening now” presentation.  

In other words, snapping my fingers are clapping in the room or hearing about talking in the room  there is no sense at all anything but the sound occurring in open air.

So when a speaker has a proper type of airiness I’m thinking of, the high frequencies essentially dissolve into and meld with the sense of the air in the room. 

No sense of artificial rolloff  or canned sound.  The atmosphere of the recording merges with the sense of air in the room I’m listening in, And so there is a more realistic “ that’s a real instrument happening in front of me in real acoustic space” sensation that also means that the timbre of the sound appears to have all the harmonics in the upper frequencies, to describe a realistic depiction of that instrument.

The thing is that this doesn’t necessarily have to be the type of stratospheric frequencies one might associate with a super tweeter or something.   It can come with the dispersion characteristics of the speaker or what is doing in the lower treble… what counts is the perception that the sound I’m hearing is unfettered and that I am sharing the same acoustic space.

(just to be clear: I’m not talking about getting everything to sound like it’s in the room with me.  When I have dialed in my system properly, which includes paying attention to the acoustics of my room, what I get is more sense of being transported to the real space of a recording)

prof, great explanation. On my system, I am sometimes suprised by a sound like drumsticks banging against each other. It comes from somewhere behind and off to the right of the right speaker. It will surprise me and I will look up from what I'm doing, like, huh? Where did that come from? Was it on my stereo or was it real? This happened sometimes when I had far less expensive speakers, but happens a lot with my new speakers.

There is no air in a recording studio. It only exists in reverberate halls. 

fynnegan, I listen to music recorded in studios, live in concert, and in concert halls. The more I think about it, however, music is air. Waves traveling through air, but the air itself makes up the waves. When we listen to music live, it fills the air. It's all over the place, whether amplified or not. I think there is some sense that it's part of the air. Somehow, I think, as music is turned into an electronic signal, it loses that sense of being part of the air. It becomes a note from an instrument traveling through the air of our listening rooms. But it no longer seems to be part of the space as it does when it's live. A good system, I think, when a good recording is played through it, restores the sense that music is part of the place--part of the air through which it's traveling. And it can make a listener feel "there." When I listen to rock n' roll amplified, at some place like the Hollywood Bowl, the sense of air is not really something I'm interested in. 

You're right in the sense that a studio is not built for an audience of people listening--it's built for recording music. And now that you mention it, I don't hear "air" in most studio recordings. Many of them are rock and I am more interested in being blown over by the music coming like one great wave. Although I do have a few albums recorded in a studio by audiophiles, like "Orpheus" by the Isao Suzuki Trio. On the back cover of the album they show where the instruments were and where the mikes were place in order to get a sense of air. Of course, most other studio albums don't go to that trouble.

My definition of "air" in a recording is a sense of space around the instruments. I have noticed that spatial cues captured in a recording around 500hz - 3khz make the recording sound wider or deeper and frequencies above that make the recording sound smaller to me, regardless of the time delay of any reverberation.

In other words, if the cymbals or vocal sibilants are very bright/sharp, my brain says "this is close by".

It does seem that vinyl crosstalk helps accentuate a sense of air in a recording. And that sharp decays of a transient in digital recordings makes it sound a little airless.

Early digital often (not always) sounds unnaturally bright and has the sharp transient decay so "two strikes against".  As much as I love Donald Fagen's 'The Nightfly' on cd, there is little to no sense of space in that recording even when compared to earlier Steely Dan releases.

Soundstream System orchestral recordings before 1985 have a decent sense of scale and air, but they are 50khz digital. It's a credit to the engineers that they set up those mics properly.  These days digital can sound as large or as small as you want, because modern processing is more accurate to the mic capture, and a talented engineer will take into account capturing the depth as well as the amplitude and tone of any given performance.

I'm lucky that  today I have speakers capable of decently recreating the recording spatial cues, but they weren't cheap (a floorstanding pair of Sonus Faber).