Silver plated copper

Some folks like the sound of tinned copper... particularly for speaker cables.   
An aside.. I use Mil spec silver plated 12 gauge Teflon insulation wire in a quad twist, 30ft/33ft and a 39ft/43ft set for my system AC power. The fact is, the silver plated wire definitely reduces the bass some to my Magnepan 20.7 speakers. WHICH IS WHAT I WANT. Since I live in an apartment building for old people.(I am an old people) I was worried about buying the Magnepan 20.7 due to too much bass... But with some care I keep the bass tamed...           
In my experience with the long runs of silver plated copper the AC wire does affect and diminish the bass a bit. As I wrote this is exactly what I want...

This just in! When the surface of a copper wire oxidizes over time the thin oxidation layer seals and protects the rest of the copper wire from further oxidation. Thus, while the effective diameter of the wire is reduced a hair, therefore resistance is increased a shade, oxidation doesn’t appear to be a real issue. 

geoffkait you are correct.A coating of oxidation does protect the rest of the wire.But the ends need to be sealed with something or they will degrade and not pass the signal properly.The good news is that it takes a very very long time to get to that point.

That’s what Deoxit and similar products are for as well as contact enhancers like the graphene paste. No big deal. Audiophiles are pretty well versed in electrical contact housekeeping protocols.

Just to clarify for everyone on this post - Copper oxidizes very rapidly but Silver does not.

A clean Copper surface prepared in vacuum forms a monolayer of Copper Oxide within minutes of exposure to air. A clean Silver surface prepared in vacuum forms a fraction of a monolayer of Silver Sulfide within minutes of exposure to air but no oxide within that timeframe. The tarnish observed on Silver is primarily Silver Sulfide.