No one actually knows how to lculate what speaker cable they need

"It is amazing what this industry can convince you pay for, without any justification."

EXACTLY! Now we're getting somewhere!

b4icu: "All the difference in conductivity is below 0.1% and no one would notice an audible difference in such a small difference in conductivity."

You see, this is the point I take issue with. Conductivity includes resistivity as a factor. This factor is the main one you use in your so-called calculations for high DF amps. I stated long ago that the contributory resistance of a normal 12, 14, 18 gauge speaker wire is going to contribute INSIGNIFICANTLY, i.e., "...such a small difference in conductivity."

This is why the use of jumper cable sized conductors as speaker wires is a fool’s errand. This is not high current, low voltage, direct current. Never will be, nada, rien, zilch, nyet, null, void, disintegrated.

You cannot,
Have it,
Both ways.

Have a great day. Oh, and please review why Edison failed with DC and Tesla prevailed with AC.

@b4icu 

No matter how good you get, beyond the standard purity of 99.90%. All the difference in conductivity is below 0.1% and no one would notice an audible difference in such a small difference in conductivity.

The whole issue of hearing a difference, in the context of everything else going on in a home audio system, becomes even more incredible when you consider many audio companies (and many cable manufacturers) still use brass (or another low conductivity alloy) in their connectors......that's right, your new $27K Lamm M1.2 Reference monoblocks use "brass" binding posts!  Amazingly, they still sound great. 

Another example is most banana connectors, which are made from a copper alloy such as brass, bronze, or beryllium copper.  Those three alloys have an associated range of conductivity of about 20 to 50 percent of IACS (International Annealed Copper Standard).  I believe the best of that group is Grade E phosphor bronze at about 48% IACS - Furutech uses that metal.  If you can find connectors made from tellurium copper, they are rated much higher, at about 93-94% IACS, which is close to the conductivity of pure copper (i.e., about 100% of IACS).  There are a few banana connectors I know of that are advertised as being made from copper -  KLE and Xhadow, and Furez that are reportedly made from tellurium copper.