Reproduced "air’’ perceived as an artefact.
The concept of reproduced air or airiness by a system denotes different connotations to different audiophiles, just like so many other ambiguous terms (tonal saturation, image density, etchiness, white-washed sound, even neutrality and naturalness), for, we do not have definitive, stable, mutually agreed and accepted definitions and metrics.
However, if one has direct familiarity or knowledge of the recorded material, judgement becomes much easier. If a system is indeed feasibly ’’neutral, linear and natural’’, then the perceived air of a recording is part and parcel of the tonal\timbral harmonic content of the recorded music. It can be considered an integral aspect, NOT an artefact, of the spatial information that a good system can presumably reproduce, assuming that the listening room is conducive to good sound and does not interfere adversely with its own non-linearities and other abnormalities.
The space around an instrument, provided that it has been captured by the recording, is not a vacuum nor necessarily an empty silence but an acoustic space of subtle and complex cross-modulating musical information; air is one of these components. Of course, a revealing and trnsparent system implies that it can retrieve this information and that it has a very low noise floor, spectral extension\linearity and transient fidelity, amongst other attributes. It also implies that the sound is leaner and lighter, rather than compacted, more ‘’saturated’’ and thicker, creating the false illusion of weight and density. Once again, familiarity with and knowledge of the natural acoustic properties and sonic propagation of instruments is the only valid criterion.
Very often, some systems\speakers inherently produce a more etched (not to mention white-washed soundstage, much to the admiration of many (usually novice audiophiles). This can be an impressive ‘’hi-fi-ish’’ sound but it is usually (especially if you know the recording well) at the expense of NOT reproducing the complete harmonic content, including the spatial information of all the components – instruments and not only – which are embedded in the soundstage. It is this incompleteness that produces this stark, etched soundstage. Usually, such systems may have a more "lit-up’’ or higher tonal centre, i.e be brighter, precisely because of these reasons, exacerbated even further by inherent spectral\phase peculiarities.
These are aspects of micro-reproduction that I attach a lot of importance and enjoy immensely because, ultimately, they facilitate a holistic, un-compromised immersion in the music. These are pre-requisite elements that bliss and transcendence are created with.
I listen always learning. Cheers, Kostas.