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  1. #1
    nightflier
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    CD Player's Ability to Skip Scratches

    What spec establishes how well a cd player can play a scratched cd? With portable players, I figure this is a factor of how large the buffer is, but this is usually not listed in component-type cd players, or is it? I suppose it is also a factor of how well the technology used inside interpolates the missing/scratched section. Therefore, I'm presuming that the price of a good player is also something to consider - with the cheapies not being as good, I presume.

    The reason I'm asking is because I'm trying to make usable copies of some of my scratched cds, but even after careful cleaning, they are still skipping. I figure that the cds are not repairable beyond what I've done with the cleaner, but I was hoping that there are players out there that would do a better job of reading scratched cds than what I'm currently using.

  2. #2
    Crackhead Extraordinaire Dusty Chalk's Avatar
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    No, not really -- I think it's more defined/confined by the spec (redbook).

    There are CD repair kits out there that do more than just clean -- they include a glaze that actually fills in the scratches with what is ultimately a transparent material of similar transparency -- you should look into one of those. link?
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  3. #3
    test the blind blindly emorphien's Avatar
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    similar index of refraction, regardless of transparency.

    As far as I can recall, the buffer just allows the player to read ahead and store data to cover for bumps, it has nothing to do with seeing through scratches. I assume that has something to do with the power of the laser and the optical pickup as well as perhaps any sort of error correction the player might implement.

  4. #4
    Suspended PeruvianSkies's Avatar
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    One thing that I have noticed is that higher-end CD players tend to enhance the mistakes such as scratches rathan than skip the scratches simply because the player is designed to get the most accurate amount of detail from the source, including scratches. My car's CD player (a pioneer) is amazing...it reads over anything...i'm almost tempted to believe you could put a blank CD in there and it would find something on it! However, my Denon 2910 finds every little detail on CD's. I even notice a huge problem when I play burned CD's on it where it picks up some of the compression and some of the blips that occur with downloaded music often.

  5. #5
    test the blind blindly emorphien's Avatar
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    Your car speakers probably lack the fidelity to reproduce the compression artifacts on low quality compressed audio, so they'll mask low quality tracks, or another way of putting it is they won't sound any better with higher bitrates either.

  6. #6
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    See this page for information regarding error correction on CDs.

    http://cdrfaq.org/faq02.html#S2-17

    Andy McFadden's treatise on CDs is a veritable gold mine of information. You can see the whole thing at http://cdrfaq.org/

  7. #7
    I took a headstart... basite's Avatar
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    I know my pc cdrom station picks up less scratches than my dad's rotel...
    but don't ask me how you can know how they do that...

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  8. #8
    nightflier
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    mlsstl,

    According to the link:

    "If there are too many errors, the CD player will interpolate samples to get a reasonable value. This way you don't get nasty clicks and pops in your music, even if the CD is dirty and the errors are uncorrectable. Interpolating adjacent data bytes on a CD-ROM wouldn't work very well, so the data is returned without the interpolation. The second level of ECC and EDC (Error Detection Codes) works to make sure your CD-ROM stays readable with even more errors. It should be noted that not all CD players are created equal. There are different strategies for decoding CIRC, some better than others."

    So what should I look for in a CD player to make sure I buy one that is better at reading scratched disks?

  9. #9
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    > So what should I look for in a CD player to make sure I buy one that is better at reading scratched disks?

    Be careful about making that your sole criteria for selecting a player. What percentage of your CD collection is so badly scratched that you'd need better than average error correction tolerance? Also note that beyond a certain point, the errors are corrected by "interpolating" the data. This is a fancy word for "guessing" meaning that you're not truly getting the real music in its full original format anyway.

    Also remember that the vast majority of CDs are easily replaced by simply by buying a new one. Even out of print stuff can often be reasonably had on eBay or Amazon. (And if you have one so rare as to be irreplaceable, shouldn't you make and be using a copy for regular play?)

    You may also find that one player recovers better than another for one type of damage but the reverse may be true for another type of damage. What you may wish to do is take some of the most damaged disks from your current collection with you as a test when you audition players. See which players best handle things to your liking.

    Another approach (probably the one I'd take) is to simply buy the best sounding player that meets your needs and don't worry too much about the damaged disk issue. Then get a copy of EAC or similar software for your computer to use in order to make the best possible repaired copy of a damaged CD if you can't replace it.

  10. #10
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    If error correction is your main criteria, I would avoid

    Denon and Marantz, based on my experience at least. I used to own a middle of the range Denon CD player, until it broke down, which was very intolerant of even slight damage, and sometime skipped or jammed even with some freshly bought disks without apparant damage. However, these disks always played back flawlessly on my daughter's cheap boom box, and back at the store when I tried to get an exchange.

    I have had identical experiences with both CDs and DVDs with my Marantz DVD player. I now own a Panasonic and so far, it has played everything perfectly, even disks that were not recognised by the Marantz. The Marantz always drove my anxiety and stress levels up because it was such a lottery as to whether or not it would recognise a disk, or jam up part way through playing. From the point of view of having a relaxed viewing and listening experience, the purchase of the Panasonic was the best thing I could have done. However, I am sure that some golden eared types will claim that the Denons and Marantzs produce better quality sound. I obviously don't belong to that set, because I find the Panny's sound very pleasing.

    PS. I have on occasion resurrected disks that would not play on the hi-fi system by copying them onto CDR on the computer, and lo and behold, the CDR copy played perfectly.

  11. #11
    Forum Regular Mike Anderson's Avatar
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    Rip it on your computer using an error-correcting software like EAC. I come across maybe 1 track on 1-in-100 CDs that is so badly damaged it can't be ripped perfectly with EAC.

    The other thing is that you can't tell if a CD results in bad errors just by looking for physical scratches. I've come across many pristine-looking CDs that require a high degree of error correction for one reason or another.

    Anyway, this is just another advantage of using computer-based systems, but I'll leave that whole debate for another thread...
    Last edited by Mike Anderson; 02-08-2007 at 06:32 PM.
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  12. #12
    nightflier
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    I have a lot of classical / opera CDs that I have acquired, mostly second hand, over the years. Some of these (perhaps 30-40 of them) arrived badly scratched. While I could probably find them again if I search hard enough, this is not inexpensive. I am finding that my CD players are rather picky about scratches (Audio Refinement & Adcom).

    Since the more expensive players are probably also more finicky, maybe I need to look for something more mainstream (like a Panasonic?) to do my dubbing. I would like to retain the sound quality as best as I can, and I am using a very nice Teac burner (not a computer) to make the copies. Now I need to find a capable source and I was hoping there was a specific spec that I could look for in my shopping.

  13. #13
    Forum Regular Mike Anderson's Avatar
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    ^^^ To repeat, you should do it on your computer. You have a computer with a CD-ROM drive, right? EAC is free, all you have to do is take the time to set it up:

    http://www.exactaudiocopy.de/

    http://users.pandora.be/satcp/eac00.htm

    Once you do that, you'll be able to extract perfect copies of all but the most badly damaged CDs. Then burn new ones -- EAC will do error checking on those too.
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  14. #14
    Shostakovich fan Feanor's Avatar
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    Thanks for the reference

    Quote Originally Posted by Mike Anderson
    ^^^ To repeat, you should do it on your computer. You have a computer with a CD-ROM drive, right? EAC is free, all you have to do is take the time to set it up:

    http://www.exactaudiocopy.de/

    http://users.pandora.be/satcp/eac00.htm

    Once you do that, you'll be able to extract perfect copies of all but the most badly damaged CDs. Then burn new ones -- EAC will do error checking on those too.
    That 'Coaster Factory' refenence looks interesting as EAC's own documentation leaves something to be desired for the uninitiated.

    I totally agree with the EAC approach. I have experimented and agree EAC can copy just about anything.

  15. #15
    Forum Regular Mike Anderson's Avatar
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    ^^^ Yep. Not user-friendly, like iTunes or something. And it has to be setup properly to make sure the error-correction is foolproof.

    But if you follow the instructions, you can get it.
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  16. #16
    nightflier
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    Mike,

    I was hoping to do this w/o a computer as I don't have one near my TV room and I'm a Linux user, and I don't believe EAC is compiled for Linux, although there are probably lots of other options out there. I'll see what I can find.

  17. #17
    Crackhead Extraordinaire Dusty Chalk's Avatar
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    I don't think you need to have a computer near your TV to do this -- just rip and burn the CD's, then play the burnt CD's in your player.

    But the linux might be a problem...
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  18. #18
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    Linux has a number of GUI front end program that use CD Paranoia for ripping and copying. That's what I use for my Linux-based operations.

    You can also use EAC under Linux with the Wine Windows emulation program. However, I prefer native Linux applications when available.

  19. #19
    nightflier
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    Quote Originally Posted by Dusty Chalk
    I don't think you need to have a computer near your TV to do this -- just rip and burn the CD's, then play the burnt CD's in your player. But the linux might be a problem...
    I meant to say my 2-channel room, which has the record player, cd plauers & Teac burner, are no where near my computer room. Hauling either back n forth would be problematic. I have in the past run an optical cable out the window to the room below, but that's not really a convenient option when I have to check things repeatedly on both ends.

    mlsstl, I had forgotten about CD Paranoia.

    Good news, I found several out of print Mahler CDs that I was trying to copy and should be able to buy them soon.

    P.S. Is the LOTR 3-cd set (the Howard Shore set) still for sale anywhere? That's another set that is all scratched up (mostly because the kids love them so much).

  20. #20
    Crackhead Extraordinaire Dusty Chalk's Avatar
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    Quote Originally Posted by nightflier
    I meant to say my 2-channel room, which has the record player, cd plauers & Teac burner, are no where near my computer room. Hauling either back n forth would be problematic. I have in the past run an optical cable out the window to the room below, but that's not really a convenient option when I have to check things repeatedly on both ends.
    The only thing you need to haul back'n'forth are your scratched up CD's and the burned copies you make from them. Don't you have a built-in CD burner in your computer? Just use that, you don't need any of that other stuff.
    Eschew fascism.
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