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From: wmartin@brl-tgr.ARPA (Will Martin )
Newsgroups: net.audio
Subject: Re: Vinyl vs. CD recordings
Message-ID: <4758@brl-tgr.ARPA>
Date: Thu, 20-Sep-84 11:45:27 EDT
Article-I.D.: brl-tgr.4758
Posted: Thu Sep 20 11:45:27 1984
Date-Received: Wed, 26-Sep-84 05:49:07 EDT
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Organization: Ballistics Research Lab
Lines: 36

With regard to the continuing CD vs. analog vinyl discussion: Is it so
inconceivable that a purely analog yet non-contact laser playback
system could be devised for existing vinyl LP (and maybe other) discs?
Of course it isn't a trivial problem, but, then, neither was color TV
or integrated circuits. It's essentially an engineering problem --
detect the reflections from a groove of laser light, while tracking
the spiral, ignoring spurious signals from random reflections or 
dirt and dust, etc. I would think that this could be done in a
totally analog manner (whether it WOULD be so done is another question,
though -- it would probably be easier/cheaper to do it by digital
conversion, and all the engineers are digital-mad these days; you can hardly
find an analog design article in the magazines anymore).
If it was done in pure analog, though, all the anti-digital arguments
are overcome, while all the reasons for digital are also achieved
(except for the minor one of the size of the storage medium; LPs
are still bigger than CDs).

However, this gives you the best of both worlds. The existing worldwide
inventory becomes playable on the new equipment, yet doesn't wear as
it is played. I would think that a sophisticated design would let the
user "tune" the position of the groove walls that is being "played"
(independently, too -- infinite channel separation) to track the
undamaged (or least-damaged) section. Media granularity could be
"tuned out" -- we could hear old 78's with no suface noise, yet 
capture whatever acoustic signal that the shellac still holds, etc.

At first, such equipment would be expensive, of course, and would
be used for making tape copies of older recordings; it should drift
down in price like everything else, though, so that it would 
eventually be something an individual could afford.

So let's see some engineers get into this -- people at various
installations on the net that read this: post this on your engineers'
bulletin boards. Let's get an "AD" system built ("Analog Disc")!

Will Martin