There are test out there. As I have to leave the computer, I would take teeh cheap way out and say go to Transparent Audio's website. (there are others, I just recall that one was good.) I think they have some of that there. But I have over the years read studies by independant folk that show the changes to the signal over a run of copper. It may be my logic trumping my ears, but it seemed to back the audible differece. Time? I don't know. I figure it must occur at the electron level long before I see it, but that aint exactly scince. Sorry to open a can of worms I can't close.
Gotta run, will check back and hopefully some pro will point out the error of my ways.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire