"The essential characteristic of the original signal" ... ?

Referring to a recording, of course. I just saw this phrase commented upon in a thread on an audio forum, its significance or meaning pooh-poohed ...

However, a competent playback system does allow this to emerge, in usually glorious ways! For someone who has never experienced this occurring it might seem almost magical, and in many ways it is remarkable, because it demonstrates the ability of the combination of ear and brain to decipher, unravel a consistent picture of a sound event in a fashion which minimises disturbing or unwanted aural artifacts not relevant to the musical performance. Especially on very poor, ancient recordings, full of detritus - on a typical, ambitious hifi system these will sound absolutely appalling, completely unlistenable to; every defect in the sound will be highly magnified, and will overwhelmingly dominate the listening experience - subjectively !!

Are we listening to the "essential characteristic of the original signal" in that situation? Of course not, our hearing is so distracted by the "noise" and "distortion" that accompanies the "signal", the musical event, that there is almost no chance of relating in an enjoyable way to the latter. So, what to do about that? Some of the options are: never listen to that recording; or, filter out by brute force frequency response manipulation, in the replay chain, what seems to be the worst unpleasantness; or ... raise the standard of the replay mechanism to the point that the human hearing mechanism is fed enough relatively clean information, allowing the ear/brain to do vital, internal, in the brain, filtering, without conscious effort. Even though the last choice may seem fanciful to many, it in fact is done all the time in the "real world" - a good example is listening to a musician busker on a busy street, performing with no sound reinforcing gear, having huge amounts of unrelated racket 'interfering' with the musical sound. The "essential characteristic of the original signal" is very obvious here; some passing by may completely ignore the performance, be oblivious to it, but others will have no trouble "tuning in" to what's important to them at that moment, and enjoy the efforts of the musician.

This should be the aim of quality audio reproduction, and is always achievable. The integrity of the production of the "art" of the music is retained in recordings, and it is only a matter of raising the standard of the replay chain to the point where one's hearing is able to distinguish the "essential characteristics" without conscious effort - this is the essence of the Art of Audio Conjuring!