No, that is not what I had posted about back to you.
Perhaps I misunderstood you what you posted then:
Silver is about 5% more conductive than Copper. The signal travels down the speaker wire at a speed about 70% of the speed of light. The difference between silver and copper is pretty much nil.
I just indicated that Vp could be more, or much less copper or silver, nothing about audibility
Of course that is not even on the horizon to consider audible, it is in the next galaxy