Mark DeBellis wrote:

An auditory example would be tempo. Suppose I am listening to two
sources, where the only difference is that one of them has a speed of
1.01 times the other. If I listen to short excerpts any difference is
below the just-noticeable-difference, but if the whole example is the
Ring cycle, I will notice that one finishes before dark and the other
doesn't, I get hungry during one but not the other, etc.

So even if quick-switch tests, on balance, are the most sensitive, that
doesn't mean there can't be things out there that don't get caught in
their net (though they may be detectable in other ways).

To come back to the SACD/CD example, my concern is whether, even if the
quick-switch test were a "null," there could be differences that the
test does not do a good job of proving the existence of. Rather than
feel assured that science tells us there could not be such differences,
it seems to me pretty apparent that every test has its limitations.

Sound plausible?

You can't do a "quick switch" test with two sources that run at
different speeds because you can't synchronize them, which would be a
dead giveaway in itself, so that is a bad example.

If you want to use that example, you will have to listen first to one,
then the other, in its entirety, then decide if the speed difference is
audible. If so, then do a blind series, listening to a known version,
then to a randomly chosen one, and decide whether it is the same or
different. In this manner you will eventually arrive at a number for a
speed differential that is at the audible threshold. That is the basic
idea of how audio research is done. You may find that speed differences
of 1.01 will be inaudible to most, but audible to some with perfect
pitch. If this is interesting enough a question for you, then do the
research and report it.

Gary Eickmeier