On 31 Aug 2006 09:28:43 GMT, John Phillips
wrote:

No-one has (as far as I know) yet provided even a credible hypothesis
for other issues with transparency, never mind any evidence.

The question of transparency of the CD goes in another direction too.
That would be how accurately you can get back what you record on it.
From that point of view it has to be said that it can be entirely
transparent. If you use a programme like Exact Audio Copy it will tell
you how many errors it has found, and how it has dealt with them. All
my CDs return zero errors, so they are transparent.

So is the question really nothing to do with CDs, but one of how
transparent 16/44.1 coding is? I suspect this to be the case, even
though it hasn't been posed that way.

If your measure of transparency is how close to the original signal
the output of such a system is, then the answer is again, very
transparent. Indeed it is far more transparent than any analogue means
of recording.

A good way to measure transparency would be to make multiple passes
through the recording chain to see what gets nasty. Given a CD you can
make copy after copy, through hundreds of generations if you wish,
without a single change in the sound that is produced at the far end.
You can't do that with analogue tape or vinyl - in a very few
generations the thing will have degenerated to unusability. Now THAT
is non-transparent. If you want a glass analogy, imagine stacking many
sheets together and finding how many it takes to render the view
invisible, with the analogue glass, it is a very small stack. For the
digital glass, you can just go on stacking.

d

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