Lesson Of The Day

Consequent our two posts savaging the iPod as a means of experiencing classical music (here and here), I received a thoughtful eMail from a reader which read,

You again and again claim that a live performance is the ideal for experiencing classical music, but in my experience live performances offer little enjoyment whatsoever compared to digital recordings. Why? Because there's so many people coughing, so many mobile phones ringing or loudly vibrating, and such bad acoustics in many venues ... that a CD where one has just the music can only be better. I still go to concerts, but more for getting together with other fans for post-concert discussion than for the performance itself. If the orchestra were performing for me alone in a well-designed hall, your preference for live performances would be understandable. I would like very much to read a further elucidation of your views on the matter on Sound and Fury [sic].

To which I in part responded,

At the present state of the art, no reproduction can capture the full acoustic range, nuance, and subtlety of a live performance even when given in a second-rate hall. And what a reproduction can never reproduce by its very nature is the acoustic "immediacy" of a live performance, so to put it for lack of a better term. The notion that with the proper recording, playback equipment, and listening room design one can have, say, a symphony orchestra, or even just a small chamber group or soloist, in one's own home is just pure Madison Avenue rubbish.

On rereading the above, it struck me that I should have expanded a bit more on the business of what I termed "acoustic 'immediacy'," and why it's a quality that's an inherent and automatic part of a live performance, but one that the recording and reproduction process by it's very nature is incapable of reproducing, at least at the present state of the art.

It struck me that I should have expanded on that matter a bit more because it's a common belief among those who are not informed audiophiles that, given a theoretically perfect recording, the theoretically perfect playback system (including the listening room acoustic) would produce the effect that whatever one is listening to in one's own listening room is actually in that listening room, be it a single instrument or an entire symphony orchestra complete with 200-voice chorus, just as it is in a live performance in a concert hall or in any other acoustic space in which one is listening.

It's that source-in-the-room quality that I've termed "acoustic immediacy" which, as I've said, is an inherent and automatic part of a live performance in a concert hall or in any other acoustic space, but is a quality forever denied a reproduction. Should you in fact ever hear any playback system that actually produced such a source-in-the-room quality, you could be absolutely certain of one thing only: that what you were hearing was a playback system positively saturated with all manner of acoustic and audio distortion — harmonic, linear, intermodulation, phase, etc. — and that what you were in fact hearing was anything but a perfectly accurate reproduction of the original source (i.e., that which was recorded for playback).

That being the case (and take my word for it, it is), what, then, should one expect to hear from a theoretically perfect playback system given a theoretically perfect recording? The answer is, an acoustically perfect audio image of the original source seemingly located somewhere behind the playback system's speakers, and heard as if one were listening on the other side of a perfectly acoustically transparent opening the size of which is just large enough for its perimeter to frame the entire audio image.

And why is that so? The answer can be grasped with but a moment's thought. There's space (i.e., distance) between the recording microphones and the source, and between the recording microphones and the boundary surfaces of the performance space in which they're recording. Given a theoretically perfect recording, the more accurate the playback system, the more of that separating space will be accurately reproduced in the playback. With a theoretically perfect playback system, all that separating space will be accurately reproduced in the playback giving rise to the audio image above described. (In practice, that characteristic audio image becomes apparent well before the point of theoretical perfection is achieved in the playback system, the more accurate the playback system, the more apparent the characteristic image.)

Not exactly rocket science, is it, and quite easy to grasp conceptually.

And that, dear readers, endeth the lesson.

There now. Aren't you glad you stopped by today?