#390759 - 01/19/00 04:08 PM
Opacity of CD blanks?
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Chip McDonald
MP Hall of Fame Member
Registered: 01/19/00
Posts: 4792
Loc: Augusta, Ga. USA
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Hello to the Right Honorable Roger Nichols,
I've been tricked into buying all the different dye formulations for CD blanks. I'm thinking I'm buying a gold cd - since This Brand was gold the last time I bought some, and then I open the package to find it's a green or blue cd.
I bring this up because as a result of this I've found myself burning preliminary mixes of my music on these things, and while many sources insist different CD burners prefer one dye over another, my Memorex burner managed fine with all of them. Likewise, the resulting cd would play in anything I put it in.
UNTIL RECENTLY.
I admit it, I've been buying cheapo blanks. I'll also admit I've got cds that skip now, and some that make certain cd players balk at playing them.
HOW DOES THIS INVOLVES YOU?
I've looked at all my old cds, and have noticed they're all very opaque with dye. I just recently bought a pack of "gold" CompUSA ultra-cheapo discs, and it turns out they're green underneath... anyhow, these things are giving me all sorts of problems, but the point is that they're almost totally transparent. (I just held an old Ricoh gold cd up to my eyes, and I can't see my computer monitor... held the CompUSA disc up, and I could read the screen through it...)
So, given that you did the "test" in your car with the different dye formulations - have you done anything similiarly based on how transparent a cd is? Have you noticed anything like this yourself? It's quite annoying, since it's beginning to look like cd blanks made with the "original" quality back when they first came out, are being repackaged as "premium" cd's, and now they're cranking out these things with practically no dye in them at all.... I remember buying a box of 10 cheapo discs from Best Buy a few years ago and they turned out to be some nice gold discs; it's looking like thsoe days are over (not to mention the manufacturers keep changing their stock!)
Thanks
_________________________
www.chipmcdonald.com (tagline inlieu of having a representational page of downloadable music for the moment...) / "big ass windbag" - Bruce Swedien
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#390760 - 01/20/00 01:03 AM
Re: Opacity of CD blanks?
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Roger Nichols
Platinum Member
Registered: 12/13/99
Posts: 1249
Loc: Miami, Florida
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Chip
The transparence really doesn't matter all that much. Remember, the laser for reading the CD ( and the one that burns the CD) are highly focused on the layer with the dye. The laser doesn't see any farther than that. Better manufacturing processes have made the plastic part of the CD flatter and more accurate, which allows a thinner coating of dye and gold or aluminum reflective coating. This is part of what makes the price of CD blanks come down. The first CD blanks were $85 each in boxes of 10.
The higher quality CD blanks also allow cutters to be faster and faster. I can cut disks at 12x with no problems, and have a 20x burner on order.
I think part of the problem is the players involved. A lot of older players will not track CD-R properly, especially on the outer diameter where flatness tollerances add to the laser reflectivity tollerences to produce a signal that can't be tracked. If you are having trouble on the exact same players that worked before, then it may be the choice of media matched to the burner.
As I have said before the best match is the media that your drive has been set up for. For everyday use, the fact that one blank lasts 200 years while another one only lasts 100 years doesn't matter. Errors may be higher on some media, but the correction factors built into CD means that you will have to have over 300 errors per second before any error correction needs to kick in, and you won;t hear anything until the errors get to 10 times that amount. For CDs that go to CD plants, the error rate is 320 per second to have a CD rejected (by the record companies, the CD plants will take them anyway).
I use a lot of TDK which you can even get at COSTCO! I have also used a lot of CompUSA disks, but I make sure that I buy the ones that say that they can be cut at 8x which means that they are of tighter tollerance.
Hope this helps
Roger
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