Best Conductor Materials by Frequency

"Copper is best from 1 to 1,000 Hz
Gold is best from 700 to 1,800 Hz
Silver is best from 1,500 to 14,000 Hz
Rubidium 4 Micron on silver best from 10,000 to 100,000 Hz"

Seems like you have two different "bests" from 700-1000, from 1500 to 1800, and from 10,000 to 14,000. Makes me wonder about the accuracy of this info...

With regard to normal(not freq. dependent) conductivity: Without getting too technical(for simplicity's sake) call the best metal conductor, silver, 100% conductive. Copper(2nd best) comes in only about 5% less conductive, while gold is 25% less conductive(than silver and just ahead of aluminum). A combination of conductors(outside of silver/copper) would create more problems than it solved. What Elizabeth is referring to is called "skin effect". The higher freqs travel toward the outside or skin of the conductor(causing a higher resistance than the lower freqs toward the center), with freq abberations and time/phase smear results. That's why Litz type wire has become popular in audio. Lots of smaller conductors(individually insulated), that allow all the freqs contained in the signal to arrive at the end of the wire coherently and intact. The Litz solution has been applied for years from tonearm wiring to speaker cables(and, of course, there are the unbelievers). I fully agree that the "results" of that "study" are suspect. The effect of the Rubidium would only be be appreciated by your local bats or Early Warning Radar System anyway. A bit more info on skin effect: (http://en.wikipedia.org/wiki/Skin_effect)

Make that, "aberrations".

Wait a minute. Rubidium is highly reactive and Never occurs in nature unoxidized. Even 4 Microns on silver would be rubidium oxide, which becomes rubidium hydroxide, which is very soluble in water.

Personally, I think this whole topic is BS. As those of us in this niche of the hobby tend to be more on the subjectivist side, if anything like this study existed, we would have most probably been hit over the head with it so many times that we'd all be parroting it.

As a former material scientist/chemist, I think he is probably mistaking rubidium for either rhodium or ruthenium, both of which are among the 8 precious metals. It makes little sense to plate a precious metal (silver) with a non-precious one (rubidium), but commonplace to plate non-precious metals (copper, nickel, etc.) with precious metals (silver, gold, rhodium...).