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From: rmd@hpfcla.UUCP (rmd)
Newsgroups: net.audio
Subject: Re: re: West of Oz CD
Message-ID: <13100013@hpfcla.UUCP>
Date: Fri, 12-Oct-84 16:38:00 EDT
Article-I.D.: hpfcla.13100013
Posted: Fri Oct 12 16:38:00 1984
Date-Received: Sat, 20-Oct-84 06:40:56 EDT
References: <3872@decwrl.UUCP>
Organization: Hewlett-Packard - Fort Collins, CO
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Nf-ID: #R:decwrl:-387200:hpfcla:13100013:000:2081
Nf-From: hpfcla!rmd    Oct 14 12:38:00 1984

The tests  which  Tony  Lauck  ran  Using a Sony PCM  adapter  to record
Sheffield  LP's were very  interesting  to me.  This is  something I had
always  wanted  to do  myself  to rebut  anti-digital  arguments.  Being
pro-digital,  I am not surprised at his results which  indicated  that a
digital recording of an LP sounds very much like the LP.

Tony was still  bothered by the fact the LPs do sound  different  and he
couldn't  understand  why Bert  White  in  Audio  didn't  hear the  same
differences  he did.  I believe that these things are largely  explained
by some fairly obvious and common attributes analog systems.

First, it is the nature of digital  processes  to be  repeatable  in the
common  objective  measures  of  frequency   response,  speed  accuracy,
distortion,   etc.  Some  people   argue  that  digital   systems   vary
subjectively  and  that may or may not be true.  However,  no one that I
know of questions the consistency of frequency response, etc.

On the  other  hand,  it is the  nature  of  analog  systems  NOT  to be
repeatable.  It would be possible to acheive  greater  repeatability  by
spending more money in the design and manufacture of equipment, but most
"high-end"  manufacturers  design for  subjective  rather than objective
performance.

There  are in  fact  large  (relative  to  digital)  variations  in  the
objective    performance   of    turntable/arm/cartridge/head-amp/preamp
combinations.  There are also large  variations in the equipment used to
record and cut LP's.  Frequency  response  variations  can easily exceed
5db when 1db is clearly  detectable.  Longterm  playback  speed can vary
over a 1-2% range.

While many would claim that these variances are not important,  they are
certainly  important for CD-LP  comparisons.  As far as I can tell, most
CD-LP  comparisons  are  done  with no good  data  about  the  objective
performance  of the analog chain  involved.  Without such data, there is
no reason to assume that  differences  are due to any reasons other than
the obvious ones.

Rick Dow
hpfcla!rmd