Redbook: only 1/4 of the master tape???

The 1/4 of master tape stuff is nonsense. I do agree with you that information is lost at every transfer stage. It just isn't a 4 to 1 reduction. You're also misusing the term compression.

I agree with the above that it is nonsense to claim a 1:4 loss. I make own recordings of choral/orchestral music so I know the master tapes before they leave the studio for the CD fabrication. I often do comparisons of master and CD and with a real high end CD rig the results are very satisfying. The better the original recording/master the better the CD: so that 1:4 thing sounds to me like another attempt to push SACD or whatever format into a market which doesn't need it.

Redbook is 44,100 samples per second.

First of all, understand the performance being recorded literally has no sampling. Rather there is a continuous stream of music, lets call it infinite (zillions) of samples per second.

If the master tape is digital, recorded at a higher resolution than the early generation digital recorders, then the sampling rate might be 96K (~1/2) or 192K (~1/4) or 2.7M (DSD).

No matter what the master tape is, redbook has been and will continue to be a 44.1K media. So I ask, what does it matter what the original master resolution is as long as it is high enough to get 44.1K min onto the CD?

So the real question is not what the master was, it is what other formats than redbook CD will sound like if we can get that higher sampling rate to a different media such as SACD or DVD-A etc.

you would need an INFINITE sampling rate to have all the information from the master tape - not likely soon, for obvious reasons!

So what is the ratio of loss, if that's the right word, going from say, 96kHz to 44.1K on a redbook CD?