Original_To:  ALLM
Original_cc:  OLIVOTTO
Newsgroups: bit.listserv.allmusic
Date:         Wed, 8 Apr 1992 16:05:00 N
From:         "OUT,
              OUT - YOU'LL NOT FEEL THE FALL-OUT..." <OLIVOTTO@ITNCISCA.BITNET>
Subject: RE: Oh no! CDs are falling!!!

Steve says:

>     I tend to agree with Marco on the discussion of CD's.  I too started
>buying them around 1985 and have had no degradation or even sign of
>any of them "oxidizing".

        I personally have polished my degree in Physics a bit, and would
like - since we're at it - to touch a point that was apparently forgotten
so far. Not a really scientific point, but a very reasonable one, I think.
        I guess that the first effect of oxidation should be a change in
reflectivity; so what would happen? The laser hits the "bit" and bounces
back in the wrong way, fooling the D/A converter. The extreme situation
would be a very heavy oxidation able to even out the surface - that is
make 0s and 1s actually disappear - but then good luck, I'll be dead when
this gets done with my CDs and egoistically I don't care that much. :)
        But (though I never tried so this is not the voice of experience)
I believe that there is no problem when the laser hits an even badly damaged
CD (I mean scratches and opaque areas on plastic), UNLESS there is a perfectly
circular gutter :) on the recorded side. This should be established, unless
you get to the point of painting it all in black (apologies to the Stones).
        So the point is: how can small spots of oxidation, whose area should
be LOCALLY very small influence the sound seriously? Please consider that
if a single bit is lost, the actual change in the sound is something like
a sigle part out of 50000 (well, out of 44100, exactly), and I am ready to
give $1,000 to anyone who has an ear able to tell a difference 100 times
larger than this one. Nobody can, physically speaking.
        More, I don't know exactly which kind of plastic is used for CDs,
but I am ready to bet that a polymeric compound is much too tightly packed
to let O2 molecules flow through. This is why you can't breathe with your
head in a nylon bag and also why the wife uses - well, in Italy it is called
"Domopak" - a sort of nylon/plastic to prevent food from being exposed to
air and corrupt.
        Conclusion: IMO, I presonally wouldn't mind a lot about this all.

        At the end of this, I would like you to know that I once went home
with a CD and put it in my reader. After 30 seconds it started jumping and
hopping around like the Mad Goat. So I went back to the shop and asked for
a replacement. They obviously wanted to try it first - and to my disappoint-
ment it was perfect. Conclusion: my Technics CD reader was dying (and in fact
it died a few days later). So, this brings up something that was written
on the back of the sleeve of the Brand X album "Do They Hurt?"... it was
more or less like this: "the listeners who have a very expensive hi-fi
set and hear a terrible screeching sound in the midst of the second track
on side B, might be interested to know that the sound is on their hi-fi,
not on the record". Heeeee!

        Be happy with your shimmydiscs!

        Ciao, Marco
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