At 07:30 PM 8/18/2004 +0000, Don Cox wrote:
>It's very hard to get facts on this as the CD blanks on the market are
>constantly changing, so by the time you read a test the type tested has
Home testing is not only feasible but (IMHO) mandatory. One site which
should be read by anyone concerned with quality and longevity of CD media
is http://www.mscience.com/ - they provide professional measurement which
is wonderfully extensive and elaborate, but far beyond my needs.
>My impression is that there is a best speed for each combination of CD
>type and writer, and that the best speed for audio may not be the same
>as for data. Some people claim to hear audible differences in sound
>quality (presumably due to error correction) on CDs recorded at various
>speeds. If you have access to a good quality sound system, you could run
>some tests on the particular batch of CDs you are using, to see if you
>hear a difference.
Aural testing is at best unreliable; there's a page in the primer at my WWW
site which cites a Philips player which explicitly has different specs for
playing pressed and home-made discs. The Philips page has since vanished
and no one else has 'fessed up to that behavior. Regardless, aural
evaluation is of little interest or value even when it is between an
original disc and its nominal duplicate - a situation which will not be
common in an archive environment.
>I have seen reports that black CDs (ie made of black plastic) give
>better results and may have a longer life. I haven't been able to buy
>any of those yet, and again they no doubt vary.
You can also see reports that green (or red) marker on the edge improves
the sound, that silver (or gold) sounds better, and so on ad infinitum.
There are WWW pages devoted to urban legends. Please check there before
passing along the unmeasurable and inaudible claims. I am reminded of the
ads for Litz and Monster speaker cable - comparing with 24-gauge 'speaker'
wire seemed persuasive, but between the super-priced cables and
twelve-gauge zip cord only those with rich imaginations could discern a
difference - and even they could not consistently identify which is which.
(NOTE: Plextor has made recorders with black trays because they offer less
reflection than beige ones. Niether Plextor nor anyone else has provided
data showing that black trays are better - only that they have less
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