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Path: utzoo!linus!decvax!harpo!eagle!allegra!alice!rabbit!jj
From: jj@rabbit.UUCP
Newsgroups: net.audio
Subject: Re: High Quality Recordings
Message-ID: <2349@rabbit.UUCP>
Date: Wed, 4-Jan-84 13:30:36 EST
Article-I.D.: rabbit.2349
Posted: Wed Jan  4 13:30:36 1984
Date-Received: Thu, 5-Jan-84 01:04:42 EST
References: <355@whuxk.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 24


A comment about Doug Sax and Lincoln Mayorga on digital recording:
	Their comments (I've read them in Stereophile and Audio) seem to
demonstrate that they do not understand some facets of digital recording.
For instance, the comments that Bill Mitchell mentions regarding digital
"zero" and analog perception of noise simply don't consider the process of
"dither" at all. <I grant you that some digital recorders don't know about
it either, which is unfortunate.>  The sole effect of dither is to provide
the same sort of BELOW "digital zero" perceptibility that is mentioned
in the analog context. 
	(This effect is easily explained by showing the spectrum of
the signal in the presence of dither, or in the presence of analog
noise.  The TOTAL noise is greater than the signal, but the LOCAL signal
to noise ratio <in frequency, perhaps in the critical band region of the
signal> is near zero dB or slightly positive, which, when coupled to the
time averaging effects of the perceptual system, provides a signal
that is quite perceptable.  <Ham C-W operators may have experienced
this effect.  :-) >  )


-- 
-Diogenes stopped here-

(allegra,harpo,ulysses)!rabbit!jj