Why does the copy sound better than the original

There was an issue in TAS where Peter McGrath, engineer for Wilson recordings, heard a copy of the CD and it sounded better. I believe the word he uttered was "impossible!"

As it turned out (on CD at least), the CD-R/RW pits are wider than the commercial CD pits, and so the copy is cleaner, and sounds better than the original. Robert Harley also commented on this phenomenon in the pages of TAS 3 or 4 years ago when it was discovered that it was the blank discs that were responsible for the better sound.

Gbmcleod wrote,

"As it turned out (on CD at least), the CD-R/RW pits are wider than the commercial CD pits, and so the copy is cleaner, and sounds better than the original'"

That's weird. The pits are narrower on Blu Ray discs and Blu Rays sound better than either CD or CD-R. Wassup with that?

Good question, and I'm no expert on that one!
It would seem the practical course of action is to email either Peter McGrath or Robert Harley, and find out if there's been an exploration of why this happens, along with whatever limitations (exclusions) they've come across.

Gbmcleod, it would be a fairly easy experiment to find out if there was something peculiar to CD-Rs that was responsible for copies sounding better than the original.

The experiment is: copy a CD-R to another CD-R and see if that copy is better than the initial CD-R. If the copy is better then there is a good chance something else is going on, something more mysterious. Did either McGrath or Harley try that, one wonders.

Geoffkait wrote:

That's weird. The pits are narrower on Blu Ray discs and Blu Rays sound better than either CD or CD-R. Wassup with that?

Comparing CD to Blue Ray may be an apples to oranges comparison. Although I can't list any, Blue Rays may sound better for other reasons than pit size. Also consider that the reason the Blue Ray pit size is smaller than CD pit size is that the Blue Ray laser wavelength is also smaller than its CD counterpart. Maybe a CD copy sounds better than the original because the CD laser wavelength remains the same size while the pit size increases (less chance of light wave diffraction?).