Which is more accurate: digital or vinyl?

Terry9, vinyl doesn't deliver the degree of consistancy needed for the measurements you're talking about, and you must have consistency for any scientific comparison. Unfortunately, digital and vinyl are apples and oranges; consequently the only comparison that can be made is subjective.

The human hearing system, meaning the ear combined with the brain's perceptions, is still not fully understood. It is definitely more sophisticated than any machine yet made. To name just one example that affects the audio world, it has been proven by research that the brain does indeed perceive frequencies above 20,000Hz, even though supposedly the ear cannot hear them. This phenomena has not been explained. However, it is my understanding that the vast majority of designers of digital audio equipment still routinely process out all frequencies above that, on the theory that we can't hear them.

I'm well aware of this phenomena. In a test I could not hear over 17,000Hz, but I can perceive at least to 20 KHz; which is why I have a tweeter that goes that high.

I can tell the difference when someone has a tweeter that only goes to 18 KHz, but I can't quite explain it.

Learsfool, it has to be "harmonics". People only think of harmonics going up the ladder, but I reason that if they go up the ladder, they have to come down the ladder as well.

Orpheus10, are you suggesting that the brain can somehow fill in the mathematical missing rungs (gaps) of the harmonic ladder? If so, it does seem somewhat plausible. If not, then what? Please accept my apologies if I'm going too off topic here.