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transmitting a performance

post #1 of 2
9/1/11 at 2:01pm
Thread Starter 

I'll be polite. No telling someone they are ignorant. I hope all of us are polite.

 

The job of an audio system is to transmit a performance.

 

First of all, if you want to point out an audio system can do a more than that (like make money for the manufacturer), I don't care about anything else. I care about live, unamplified, acoustic music---and transmitting that music to another time and place (i.e. recording it and playing it back).

 

Now, I understand perfectly well that we have a well-developed set of theories for designing ADCs/DACs and amplifiers. On the standard measures of performance their distortion in vanishingly small.

 

But, speakers and microphones are far from perfect. That is one obvious hindrance in recreating a live acoustic event.

 

But there's a problem even deeper than that. Microphones normally don't capture, and speakers normally don't reproduce, the 3-D wavefront.

 

So right away we have a problem, which is that our re-creation is distorted in easily identifiable or measureable ways.

 

Now, I'm curious to know, at this point, how we would evaluate a particular system (which would include microphone and speaker brands, placements, and listening room acoustics). How do we know whether one of them is consistently closer to the original performance?

 

One obvious problem here is that different listeners will have different opinions. But that's not a problem, to me. If you find that to be a problem, you might want an objective measurement of microphone and speaker behavior, placements, and listening room acoustics. Is there such a measurement?

 


Edited by mike1127 - 9/1/11 at 2:45pm
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post #2 of 2
9/2/11 at 6:52am
I believe we've clashed on this subject before Mike! I'm going to make my point, because it's pertinent and then I'll leave this thread and you can take what I say and do with it as you will.
Quote:
Originally Posted by mike1127 View Post

The job of an audio system is to transmit a performance.


I maintain that this is a false premise. When we go to a live performance we are immersed by expectation and the sights and smells around us, the feeling of being part of an audience, the drama of the situation aided by the lighting of the stage and the movement and expression of the performers, etc, etc, etc. All of these things dramatically affect our perception of the performance and makes it an experience. An audio system cannot capture any of these things and does not attempt to do so. In other words, an audio system is not and cannot be designed to transmit a performance, all it can do is capture and transmit sound waves, nothing else.

Furthermore, if we are talking about the majority of studio recordings, then the last thing we would want is to transmit the performance. Unless you want to hear a whole day of drum recording, then the guitars being recorded on another day then the vocals the next day, etc. In other words, there is no "performance" as such, any illusion of a band's performance is manufactured at a later date, during production.

Quote:
Originally Posted by mike1127 View Post

But, speakers and microphones are far from perfect. That is one obvious hindrance in recreating a live acoustic event.

 

But there's a problem even deeper than that. Microphones normally don't capture, and speakers normally don't reproduce, the 3-D wavefront.

 

So right away we have a problem, which is that our re-creation is distorted in easily identifiable or measureable ways.

 

Now, I'm curious to know, at this point, how we would evaluate a particular system (which would include microphone and speaker brands, placements, and listening room acoustics). How do we know whether one of them is consistently closer to the original performance?


I'm not sure what you mean by "3-D wavefront" but every aspect of a sound wave can be measured and captured. But I agree that mics and speakers are not very linear and of course we can measure their linearity and the linearity of every piece of equipment in the recording and playback chain. We can even measure the performance of speakers in a room acoustic but that requires some pretty specialized equipment.

Your last paragraph which I've quoted above: Again, we cannot measure equipment linearity relative to a performance because we cannot measure or capture a performance, only the sound waves produced during a performance.

G
Edited by gregorio - 9/2/11 at 6:54am
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