Freezing CDs?

Discussion in 'Hi-Fi and General Audio' started by spica, Apr 10, 2009.

  1. spica

    Seeker_UK

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    I used to think that until I read up about it to understand some of the issues around this topic. Came as a surprise:

    http://electronics.howstuffworks.com/cd1.htm

     
    Seeker_UK, Apr 27, 2009
  2. spica

    tuga

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    tuga, Apr 27, 2009
  3. spica

    Haselsh1 Shaun H

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    The polycarbonate is sputter coated with a layer of aluminium which is by it's very nature, heat and cold sensitive.​
     
    Haselsh1, Apr 27, 2009
  4. spica

    Haselsh1 Shaun H

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    The laser light is reflected by the aluminium and not the polycarbonate. Therefore, it could be that the laser reading device may well be affected by changes in that aluminium layer brought about by extreme cold.​
     
    Haselsh1, Apr 27, 2009
  5. spica

    Seeker_UK

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    So if I have a very thin layer of aluminium which is bonded to a thicker layer of non-heat sensitive material and underneath a layer of acrylic (also unreactive), it's going to be able to move and have an effect on the pits on the plycarbonate layer?

    How?

    Also, and I find this puzzling, if a temperature change of say -30C can affect the data extracted from a CD, wouldn't you say that's a pretty fundamental design flaw?
     
    Seeker_UK, Apr 27, 2009
  6. spica

    Haselsh1 Shaun H

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    I wonder if PWB has actually read this thread. He must love it...!!!​
     
    Haselsh1, Apr 27, 2009
  7. spica

    Haselsh1 Shaun H

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    I'd say that 16 bit 44.1kHz is a fundamental design flaw.​
     
    Haselsh1, Apr 27, 2009
  8. spica

    Seeker_UK

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    Could be, but we're not talking about extreme cold. We're talking about what a deomestic freezer can achieve. :)
     
    Seeker_UK, Apr 27, 2009
  9. spica

    Haselsh1 Shaun H

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    Polycarbonate and acrylic are indeed insulators with a very high heat transfer coefficient so conduct heat very slowly but one thing is certain, they will eventually conduct that heat/cold. Aluminium on the other hand has a very low heat transfer coefficient and so is readily changed by extremes of temperature. How this would manifest itself in the construction of a CD I have absolutley no idea but if people are noticing a difference in the sound of CD's it appears likely that there is a change. Only a survey of a few hundred or maybe thousand individuals would verify this one way or the other.

    By the way... Acrylic and Polycarbonate are not unreactive.​
     
    Last edited by a moderator: Apr 27, 2009
    Haselsh1, Apr 27, 2009
  10. spica

    Seeker_UK

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    OK, poor choice of words but compared to Aluminium they are pretty unreactive to heat with regards to expansion / contraction.

    Other than that I think we agree.

    As I said previously (or rather I hope I did), there is indeed a noticeable change for some people. What the cause is, who knows, I think it's for one reason and others may believe it's for another.

    I would offer to listen to a frozen and unfrozen CD but I believe that my system isn't going to be that discerning and nor are my ears.
     
    Seeker_UK, Apr 27, 2009
  11. spica

    tones compulsive cantater

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    People notice a change because they believe there can be one, whereas the fact is that there can't be.

    Neither is reactive, either actively or passively. Naturally one can always find something that will react with something else - even something as inherently reaction-resistant as gold (so unreactive that it's the only metal found in an elemental state) can be persuaded to undergo chemical reaction, if you use something nasty enough, such as aqua regia.

    Under normal service conditions (including use as CDs), acrylic and polycarbonate do not react with anything. The ultimate enemy of all polymers is light, which will eventually break down the polymer chains and cause the polymer to degrade, but that'll take a very long time. In addition, the polymers will contain light stabilisers to counteract the effect.
     
    tones, Apr 27, 2009
  12. spica

    Haselsh1 Shaun H

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    Mmm... I feel that I am in complete agreement with you regarding one's ears and for that main reason I am not going to be freezing my CD collection. If there is a change, and it may well be plausible, I do not honestly think that I would be able to hear it so obviously and, really, am I that bothered to start freezing around six hundred CD's...??? No is the short answer to that one.​
     
    Haselsh1, Apr 27, 2009
  13. spica

    Haselsh1 Shaun H

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    Which of course comes directly back to what I said.​
     
    Haselsh1, Apr 27, 2009
  14. spica

    Haselsh1 Shaun H

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    Would you care to offer some form of proof...??? Just because you state it is a fact unfortunately doesn't prove anything.​
     
    Haselsh1, Apr 27, 2009
  15. spica

    tuga

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    Which makes one wonder why they chose aluminium+acrylic+polycarbonate... What where they thinking???:confused:

    Ah, they were actually thinking... :MILD:
     
    tuga, Apr 27, 2009
  16. spica

    Haselsh1 Shaun H

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    Which then makes one wonder why they chose 16bit and 44.1kHz sampling which is so inherently dreadful... oh I see... it's all they had and they had to do something to start earning money all over again.​
     
    Last edited by a moderator: Apr 27, 2009
    Haselsh1, Apr 27, 2009
  17. spica

    tones compulsive cantater

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    Sorry, I can't see that it does. Under normal service conditions, the polymers involved last many years and will degrade because all things do in time, not because they are especially degradable. By any reasonable definition of the word, they are unreactive.
     
    tones, Apr 27, 2009
  18. spica

    tones compulsive cantater

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    No proof is necessary. There are some ideas that are so intrinsically wrong that no amount of belief therein will make them right. This is one such idea. It does not work because it cannot work, because there is nothing to work. The pits are in no way changed by freezing, which means that the data remain the same. (Yes, I have tried it, no, it didn't work). It "works" only because people believe it does. I have no problem with that; if folk enjoy their cool CDs, good for them.
     
    tones, Apr 27, 2009
  19. spica

    Dev Moderator

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    Tony, one possible explanation may be that by freezing and wiping away the condensation the CD may be physically cleaner, so less prone to errors? Unlike a computer a CDP obviously doesn't re-read, so maybe. Otherwise I agree, a sequence of 1s and 0s remain the same. This can be proven by freezing a data disc and reading a file before and after.
     
    Dev, Apr 27, 2009
  20. spica

    DavidF

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    Not sure as that proves any thing Dev.

    Te computer either reads it or doesn't?
     
    DavidF, Apr 27, 2009
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