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From: dsj@alice.UUCP (David S. Johnson)
Newsgroups: net.audio
Subject: Digital Trojan Horse?
Message-ID: <4189@alice.UUCP>
Date: Thu, 22-Aug-85 08:40:36 EDT
Article-I.D.: alice.4189
Posted: Thu Aug 22 08:40:36 1985
Date-Received: Sat, 24-Aug-85 15:49:45 EDT
Organization: Bell Labs, Murray Hill
Lines: 34

Has anyone else on the net heard of/thought about the claim
that digitally recorded (vinyl) LPs are destroying our turntables?

This hypothesis is argued in Neil Levenson's audiophile column
in the May/June 1985 issue of FANFARE (Levenson is a golden ear
who would do THE ABSOLUTE SOUND proud).  He claims that digitally
recorded vinyl discs generate ultrasonic products not present
in analogue discs (he claims these have been measured), which
somehow cause micro-cracks in turntable bearings (he claims
these have been seen under electron microscopes) which by some
mechanism greatly increase the short-term speed irregularities
of the turntable, especially audible on piano music.

Buttressing this argument are claimed measurements of
these speed irregularities, on a variety of new turntables.
Measurements were supposedly made both before and after digital
records had been played, with analogue records used as controls
so that the effect could not be due just to playing ANY record.
2-4 hours of digital play is supposedly enough to have a noticeable
effect and 12-15 is disasterous.  The effect does not go away
and applies to all subsequently played records, both digital
and analogue.

The implication is that the digitally-recorded LP is something
of a Trojan Horse: take them into your house and they will destroy
your turntable, thus making it necessary for you to buy a CD player,
since if nothing else CD players are rock-solid with respect to
speed accuracy.  (According to Levenson there IS nothing else;
he is of course firmly in the anti-digital crowd.)

Do these claims about speed accuracy damage seem at all plausible
to the experts on the net?

David S. Johnson, AT&T Bell Laboratories