Br3098,
Putting the science aside for a minute, have you listened to different digital cables? Who knows why scientifically, but there is a difference, at least to me along with a lot of other people.
One key factor may be this, as explained to me by a manufacturer:
"A cable is much more than the wire. You can use the best wire in the world, but if the wire connection to the connectors is not done well, the cable won't be good. A cable starts where it connects to and receives the input signal. The connector, the connection, the wire and the shielding and grounding determine if the signal passed in is the same as the signal coming out and entering into the receiving component."
There is definitely science in that, so maybe it's that aspect that determines "the sound quality" more than whether the wire is cheap copper, better copper or silver.
Tbg has an extremely nice system, so the highest quality Firewire will be audible.
Chuck