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Conference cookie::notes$archive:cd_v1

Title:Welcome to the CD Notes Conference
Notice:Welcome to COOKIE
Moderator:COOKIE::ROLLOW
Created:Mon Feb 17 1986
Last Modified:Fri Mar 03 1989
Last Successful Update:Fri Jun 06 1997
Number of topics:1517
Total number of notes:13349

1407.0. "HAVING SEEN THE LIGHT" by AYOV27::KIRKPATRICK () Fri Nov 25 1988 06:01

    I recently purchased a SKY CD, but found that the top surface of
    the CD was slightly pitted. Obviously I took it back.
    
    The assistant held the CD up to a light, and we could see some pin
    holes of light. He said that it didn't affect the recording, but
    readily agreed to replace the disc.
    
    I carried out a quick examination of my CDs and found a couple which
    had a pin hole of light.
                                       
    Is this common ?
    Does it affect the recording ?
    Is it an indication of the "Nimbus panic" ?
                            
    
    I.K.
T.RTitleUserPersonal
Name
DateLines
1407.1Pin Holes CommonUSRCV1::THOMPSONPPaul Thompson, Rochester, NYSat Nov 26 1988 11:435
    I believe that you will find that it is the exceptional CD which won't
    show any pin holes when held up to the light.  I have yet to encounter
    one of these pin holes which affected the sonic quality of the disc
    in any way.  (My current collection is probably around 130 discs.)
    
1407.2The Hole in the ZeroMARVIN::BIGELOWBruce - DECnet-VAXMon Nov 28 1988 10:1419
    I have 250-300 CDs and have encountered lots with pinholes.  Two
    of these did cause problems.  One was in the directory and I could
    not direct-access any of the tracks - all I could do was start the
    disc at the beginning and let it play.  An exchange solved the problem.
    Another was large, and black-edged.  It looked like a burn of some
    kind.  That one cuased a very audible pop in the music.  Again,
    an exchange solved the problem.
    
    I have noticed that the polygram labels in particular seem prone
    to little holes.  I've been told that they use a thinner aluminum
    film than most people, but don't know if this is true.  I have never
    noticed any problems other than the two mentioned above (the second
    of which was a L'oiseau-Lyre (Polygram) and the first of which was
    a Nonesuch (Warner).  And at least 100 of my CDs are on one or another
    of the Polygram labels, and most have a few little holes.  The labels
    that I almost never find holes in are Telarc and CBS, if anyone
    cares.
    
    B
1407.31-beam lasers have problems with themTON80::CAMPBELLIt's only a CRIME if you get caught!!Mon Nov 28 1988 12:017
    I found that Electra also have pinholes, especially the Harry Chapin
    CD's I have.  I used to have a single beam laser which didn't like
    the pinholes and it 'skipped' whenever it hit them.
    
    I then bought a 3-beam laser player and the CDs work fine.
    
    Smc
1407.4Don't worry, be happy....BETHE::LICEA_KANEMon Nov 28 1988 12:5319
    If you think "pinholes" are a problem, you've never looked closely
    at the grooves in a vinyl record.
    
    Pinholes, that's what ECC is for.  Part of the CD spec states
    how many, and what size, pinholes a CD is allowed to have.
    Basically, a pinhole is small enough to be corrected by ECC
    (inaudible, no loss in information) but not large enough for
    interpolation to come into play (audible, loss in information).
    
    If you hear anything audible from pinholes, the pinholes don't
    meet spec or your player can't correct for correctable errors.
    If you get skips over pinholes, the pinholes don't meet spec
    or your player can't track a trackable disc.
    
    1-beam or 3-beam lasers shouldn't have a whole lot to do with
    it.
    
    								-mr. bill