"MZ" wrote in message
...
But what is it? Do you not agree that if the waveform produced by
amplifier A perfectly matches the waveform produced by amplifier B, there
will be no difference in sound?

Of course. Unfortunately, they don't measure as accurately as you think
they
do.

Yes they do. Today's modern test equipment is extremely precise. Much
more precise than our senses. It can introduce a virtually nonexistent
impedance (thank goodness for op amps) and has an error of measurement far
below what you think it is. The error is usually listed in the manual or
on the back of the machine itself.

No, you still don't get it. You still think, for example, that because we can
detect parts per billion, that scientific measuring devices are more precise
than our tongue and nose. It's not a question of precision, it's a question of
accuracy. Those tools are not measuring the same way we're measuring. It's too
complicated. The wine example was a good one. Even though they can do a
chemical analysis on it, they still can't determine which blend of tastes and
smells will make up a good wine and which will taste best. Sure, they can
detect obvious things like spoilage or the presence of some awful chemical, but
they can't figure out which wine would be preferred in a blind tasting.