Audio Fidelity, Hearing, and our Educational System

What follows is a piece of a WFAE (World Forum for Acoustic Ecology) thread spun out of questions relating to MiniDisk audio recording quality specifically and, in general, audio recording fidelity relative to the original acoustic source. It includes thoughts on:

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Pellegrino's message: "This is in response to Mark Kolmar's 1/21/98 message included below this message.

Quotes out of context stand a good chance of being misleading. So for the purpose of clarity I'll repeat what I wrote on Tuesday, January 20, 1998: "For the notion of audio fidelity to make any sense there should be a reference source, something to be faithful to. That reference source (the real world) is the actual audio environment as processed, organized, and interpreted by our hearing system - the combined output of our ears, flesh, body cavities, bones, nervous system, and memory. It seems exceedingly rare to find any discussion of audio grounded in that "real world" of experiencing the actual source. Typically the focus is on "real-world frequency response" of the audio gear relative to other audio gear. Seems like roots in the ether blown around by the winds of commerce."

My statement was not "in opposition" to what Mark said. Rather it was an observation triggered by what he said. For 30 years as a professional cultivator and harvester of the audio field what I've been observing and continue to observe is that audio folks tend to be brainwashed by the audio industry (including the production, retail, and academic wings) to accept the lowest common denominator approach as the standard. Since there is so much truly awful audio reproduction most folks are more than happy to settle for an average or mediocre level which, in contrast to the awful, is at least acceptable.

Not only did I read Mark's "original response", I've given considerable thought to its implications. And, of course, I do take issue with the reproduction of audio when it's based on the average ear being a determining factor in the design and quality of the audio tools that populate my personal studios, those I design for others, and what I find at the venues for my gigs.


Mark Kolmar's message: "On Tue, 20 Jan 1998, Ron Pellegrino wrote:

"It seems exceedingly rare to find any discussion of audio grounded in that "real world" of experiencing the actual source. Typically the focus is on "real-world frequency response" of the audio gear relative to other audio gear. Seems like roots in the ether blown around by the winds of commerce."

I get the impression your statement is in opposition to what I said. My original response is attached. Clearly you did not read it, or you have some fundamental issue against reproduction of audio. Or maybe you just don't understand the terms.

A specification like "20Hz to 20KHz, +/- 3dB" means that the frequency response in the signal coming out, relative to the signal coming in, over the given frequency range, will differ by no more than 3dB up or down. Of course this is only one measure of the changes produced by a certain piece of gear, anywhere in the chain from microphone to speaker.

Then I went on to describe a few basic limitations of recording and playback equipment, which has everything to do with the limits of the equipment's ability to record and reproduce any and all sounds in nature."


Continuation of Pellegrino's message from above:

"Again, in the interest of clarity, I'll repeat the full statement that Mark is quoting out of context:

What Paul is saying (the message from Paul Berolzheimer: "As someone who is trying to encourage the state of the art of recording technology to improve rather than deteriorate, I feel I have to point out that minidisc recorders use heavy data compression- an algorythm they call Adaptive masking. Basically, this system is based on the assumption that we can't hear anything that is 30 dB below anything else in the same part of the spectrum, & therefore throws away any information that falls into that category. I know from my own experience that this assumption is simply not true, not consistant from one human to another or from one listening environment or system to another. I personally don't want my recording device deciding for me which part of the signal is important and which part isn't, I just want it to record faithfully whatever I'm feeding it. Technology these days is getting quite amazing, let's use it to move forward rather than backwards")is consistent with the audio engineer's methodology of testing the perceptual capabilities of a group of people with non-musical test tones, then taking the average of their responses and using those averages as the basis for designing systems that are "good enough" for normal (not necessarily musically perceptive) consumers of audio products. The standard 20 Hz to 20 kHz frequency response of audio gear is also a good example of the failure of that approach. Frequencies above 20 kHz beat against each other (heterodyne) to create difference tones that sound below 20 kHz to affect timbre by reinforcing spectral components plus adding dynamic colorations. Below 20 Hz we feel (hear) in our flesh, our body cavities and our bones. The price we pay for the mass distribution of audio products is the deafing down of society."

In that statement the pressure deviations relative to the 20 Hz - 20 kHz frequency band or any other of the numerous distortions inherent in even the best recorded sound are simply not relevant to the point I'm making. My point is that the audio engineering profession decided that we will not have access to frequencies beyond a "scientifically" determined range even though those frequencies play a crucial role in the original acoustic environment. I do take issue with that position. But, given that my game is affordable emerging technology in the arts, I don't intend to quit the audio end of my business and nor to stop spending loads on gear. It does mean that more and more I attend non-amplified acoustic events and avoid recorded and electronically reinforced audio whenever possible. When there is no way out, I specialize in tunings, work-arounds, and other assorted fixes based on a lifetime of attentive listening in the acoustic world."


Mark Kolmar's message: ""Pellegrino said: Below 20 Hz we feel (hear) in our flesh, our body cavities and our bones."

The 20Hz to 20KHz specs are not absolute. Also they are meaningless without some reference point, e.g. 20Hz to 20KHz +/- 3dB. In a digital system, the high end is capped by a sharp anti-alias filter, at a frequency somewhat lower than 1/2 the sample rate. The low end can go down to DC (0Hz). However, the response of an ordinary pair of speakers rolls off quickly at the low end, so that a 16Hz tone may produce only a buzzing or no perceptible tone.

In an analog system, the low end contains a great deal of electrical noise. The high end is theoretically unlimited, but in practice anything less than reel-to-reel with a high tape speed (15ips or faster) will roll off quickly.

I don't wish to get into an analogue vs. digital debate, but only to comment on real-world frequency response. As for MiniDisc, I hear a certain lack of detail and space due to the perceptual encoding. This would likely make no difference through a boombox, Walkman, or in the car."


What Mark Kolmar is saying above is a perfect example of my earlier observation that "It seems exceedingly rare to find any discussion of audio grounded in that "real world" of experiencing the actual source. Typically the focus is on "real-world frequency response" of the audio gear relative to other audio gear. Seems like roots in the ether blown around by the winds of commerce." It is truly unusual to find students or educators in the audio field with a firm grasp of psychoacoustic fundamentals. However they do love to cloud the air with technical trivia, anecdotes, and equipment comparisons. -RP


Date: Thu, 22 Jan 98 09:58:35 EDT
From: "David Staudacher"
To: ronpell@microweb.com
Subject: Re: Your thoughts

"I was confronted with a hideous example of *exactly* what you're talking about today at my son's school (he's in the first grade). I normally don't take him to school so I wasn't aware of this until today. In _every_ classroom, the school day begins with a "student produced" video which culminates with the U.S. "pledge of allegiance". Throughout the video there is the near constant drone of automatic gain induced audio feedback which is _so_ loud that as to _saturate_ the classroom and is actually _painful_! Meanwhile, NOT ONE STUDENT IS ACTUALLY WATCHING OR ACTIVELY LISTENING to the video! It's horrible to imagine but probably true that this experience is hardly unique to my son's school. In thousands of schools across the U.S. alone this is probably how a typical school day starts.

And why?? I think it's because of _exactly_ what you are saying. That no one dares question these systems, designed and installed by "experts" who, after analysis and design based more on abstractions than "real world" observation, have decided _for us_ that these are the technologies we need and want. Why is it so hard to stand up and say "Stop! This is wrong!"? I think largely because our society has become so over-specialized that everyone can look the other way and say "It's not MY responsibility." Yet, if any one of those "experts" were to actually _sit_ in my son's classroom and _hear_ how horribly and cruelly his product was being used, he would surely say: "STOP THIS AT ONCE!! THIS IS HORRIBLE AND CRUEL!!"

I follow the WFAE list faithfully but I hardly ever say anything. To tell the truth, I'm rather disappointed that the focus of the list seems to have so little to do with noise pollution anymore. Most of what I read has more to do with _adding_ sound to the environment than conserving natural sound and limiting man-made "sound waste".

But there's another mailing list concerned with noise pollution. In fact, I am the list administrator. I call it the "Quiet List". I guess you could consider this an invitation to subscribe. It's easy to subscribe, just e-mail "majordomo@igc.org" saying "subscribe quiet-list"."


At the time of this writing I've been a subscriber to "Quiet List" for several weeks and I've found the postings to be abundantly thought-provoking on the subjects of quiet and noise pollution. - RP



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