Once upon a time on usenet Phil Allison wrote:
~misfit~ wrote:

----------------------


CD-RWs required more sensitive optics on the part of the playback
device, CD-Rs however once they were written with PCM audio data
(_not_ mp3 files) and finalized IIRC were essentially the material
equivalent of a commercial Red Book audio CD and should work on any
CD player, even ones from the 1980s.

Actually CDRs are much less reflective than 'pressed' CDs and as
such some older CD players don't have the laser power needed to get
a good (reflected) signal.


** CDRs use the same metallised ( Gold or Silver) reflecting layer as
a normal CD.

Yes. The difference is in the construction of the non-refecting areas. In a
CD they're pressed into the refecting later and become 'pits' whereas with a
CDR a dye layer between the reflecting area and the pickup laser is 'burned'
changing it's reflectivity index. The result, done on a modern high-quality
burner on a modern high quality blank and at a reasonable speed is close to
a pressed CD w/r/t readability. However a lot of CDRs are burned too fast
and / or are not top quality blanks resulting in a less-well defined change
from reflective to non-reflective which can give some older readers
problems. Especially when they were first on the market.

It's not so much of an issue these days as the quality of blanks has
improved considerably and the price of good quality ones has come down.
There used to be a large difference in price between the cheapest discs and
the best discs and and a corresponding difference in readability. This could
give some older players - especially those with lasers that were starting to
weaken - issues reading CDRs.

They play perfectly in my 1982, Sony CDP101.

My 1986 Philips CD 160 and my 1987 Sony CDP-17F will both read all of my
newer CDRs but used to struggle with ones I burned in the early days when
discs and burners weren't as good. I still have some of those CDrs and even
though they've been looked after and are in good physical condition both of
the older players struggle with them.

I don't have an older player any longer and will probably be getting rid of
those two soon as them not having remotes and me having mobility issues
makes it so I hardly use them these days anyway.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)