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Path: utzoo!watmath!clyde!burl!ulysses!allegra!princeton!rocksvax!dave
From: dave@rocksvax.UUCP
Newsgroups: net.audio
Subject: Re: error correction in cd's
Message-ID: <2000013@rocksvax.UUCP>
Date: Tue, 11-Jun-85 14:35:00 EDT
Article-I.D.: rocksvax.2000013
Posted: Tue Jun 11 14:35:00 1985
Date-Received: Wed, 12-Jun-85 08:02:04 EDT
References: <679@charm.UUCP>
Lines: 21
Nf-ID: #R:charm:-67900:rocksvax:2000013:000:922
Nf-From: rocksvax!dave    Jun 11 14:35:00 1985


Most disks are somewhat transparent because the wholes are designed to be
1/4 wavelength of IR laser light which is lower in frequency than visible
light.  This will let a small amount of visible light through, I think what
the original poster was noticing was those bright little spots thought the
normal "grey" haze.  I do beleive these wipe out more than 1 bit of data
thus invoking the error corrector.

I looked through most of my CD's for this when I noticed the "swiss cheese"
quality of the CBS "Made in USA" CD I bought.  All of the "Made in Japan"
CD's seemed to have at most 1 or 2 of these "bright" spots.  The "Made in
Germany" ones had up to about 4.  Now I can see why the US plant has a 
90% or worse fall-out rate!!!

Despite any of these my Yamaha seems to play through it all without any
discernable noises.

Dave

arpa: Sewhuk.HENR@Xerox.ARPA
uucp: {allegra,ihnp4,rochester,amd,sunybcs}!rocksvax!dave