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From: Thomas Peitzmann <peitzmann@...-muenster.de>
Date: Thu Feb 14, 2002 1:13pm
Subject: Re: OT: 96kHz and stuff...

At 10:58 Uhr +0000 14.02.2002, "Mark Lennox" <mark@e...> wrote:
 >I know most people cant hear above say 17kHz or so, and thus the argument
 >for 96kHz sampling rate seems ridiculous.
 >
 >However, you have to remember that instruments, voices, etc... produce
 >overtones, harmonics, whatever stretching far above the audible threshold.
 >If these tones interact to form beat frequencies the resultant frequency
 >could be within the audible range.
 >
 >While recording you may record the beat frequency but not the original 
tones
 >that produced it - does anyone think that this would matter? Is this why
 >people claim that 96+kHz smapling rate is much better? Is it all in their
 >heads :)

Superimposing two frequencies (sinusoidal) on a linear system (like
air at reasonable pressure) produces no new frequencies. You hear the
beat frequency from audible tones, but that's a perceptive phenomenon
(which doesn't say it is non-existent). If you look at the
corresponding frequency spectrum it will still be just the two
sinusoids you started out from. So you can't hear the beats if you
can't hear the frequencies.

It's a totally different story for non-linear (modulating) systems,
though, which part of the human auditory system probably is. Then
it's a question of whether the cutoff of the high frequencies occurs
before or after the non-linearity.

Best regards, Thomas