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From: wjm@lcuxc.UUCP (B. Mitchell)
Newsgroups: net.audio
Subject: Re: CD Musings
Message-ID: <147@lcuxc.UUCP>
Date: Tue, 15-Jan-85 11:12:22 EST
Article-I.D.: lcuxc.147
Posted: Tue Jan 15 11:12:22 1985
Date-Received: Wed, 16-Jan-85 05:57:13 EST
Organization: Bell Communications Research, Inc.
Lines: 23


I found Bob Niland's comments about CD's quite interesting and agree with them.

However, I have some problems with gould!jon's comment about the 44 kHz
sampling rate being adequate.
He is correct in stating that a 44 kHz sampling rate will perfectly reproduce
a 22 kHz signal (the Nyquist sampling theorem).  However, that is not the
problem.  The problem is that, frankly, 22 kHz may not be adequate for *true*
high fidelity reproduction.  Although the medical texts state that Homo Sapiens
can hear frequencies between 20 Hz and 20 kHz, these figures refer to the
Fundamental frequencies. (and that isn't totally true either, some people, like
myself, can hear 25 kHz tones - which is why ultrasonic alarms in department
stores make me reach for the Excedrin).  However, musical instruments do not
produce pure sine wave tones, but rather complex waveforms with high amounts
of harmonics.  Since the third harmonic of a 14 kHz cymbal or bell note is
42 kHz, 22 kHz is nowhere near adequate for proper reproduction.   Long term
readers of net.audio will remember that this has always been one of my main
concerns about the current CD standard.   This is NOT and should NOT be
interpreted as an anti-digital comment, I just want the digital sampling rate
to be high enough to reproduce ALL the musical information.
Regards,
Bill Mitchell ({ihnp4!}lcuxc!wjm)