If I may add a couple of comments, without straying towards promotion of our cables. Apologies if I don't get that balance right.
A single set of LCR figures for a cable does not fully describe a cable. This is heresy to many EEs, but when the current scientific theory, which is an abstraction of reality, fails to describe what we experience, then we need new theories, and we need to test them. One of the theories we have been working on (together with experts in Physical Chemistry) is that a metal will possess a small amount of mechanical resonance that relates to the physical characteristics of its atomic structure. And that this mechanical resonance can impart a tiny electrical resonance when it carries an AC signal. This tiny electrical resonance can cause a persistent phase shift that creates a sonic signature. Null tests will show differences between cables, but they are in the noise floor and so very hard to isolate and identify, so if the theory has any validity you have to also believe that the ear/brain is very highly susceptible to phase anomalies that the ear/brain does not commonly encounter, and this creates fatigue for the ear/brain system. It is also possible that some people are a lot more susceptible to these anomalies than others.
Call it bollocks if you like, and it very well might be, like many an untested theory, but it is a theory that fits our experiences and we are working on how to measure and verify this.
We think that this can possibly explain why there is a pattern to how people describe their reactions to copper, or silver, or gold , or platinum, etc wires. And, without getting side-tracked, it also relates to why we think burn in has an audible effect - but that is another subject.
On the topic of this thread, copper seems to have a resonance in the lower mids and upper bass, and pick up noise easily (the latter, we think due to the small mass and density of the copper atom). Silver seems to have a resonance in the upper midrange and lower treble, and pick up less noise. Gold appears to have a very broad-based resonance centered on the mid midrange and pick up less noise than silver. We have been modelling atomic characteristics of these atoms to see if we can find a potential causal relationship with these observations, but funding for this research is slight.
Certain alloys of these or other metals can counteract these resonances, but also can create their own. The development of alloys that sound good is quite an art - that one or two appear to have mastered to some degree. But most alloys we have listened to smooth the resonance nicely over a wide range but the resonance is still there and tends to obscure detail. An alternative approach is to use solid wires of different gauges and metals. Another alternative approach is to coat one metal with another, or sometimes with more than one other metal.
Getting more specific about gold - using solid gold wires can result in dense tonal colours and warm harmonic balance without obscuring detail, and to my knowledge there is no other way to get this to quite the same degree except by using solid gold wires somewhere in the mix.
Other aspects of the design of a cable are of course incredibly important too, and so it is as easy to make a gold cable sound too 'gold' as it is to make a silver cable sound too 'silver'. The wire material is just an ingredient and using gold does not guarantee a great cable any more than it guarantees and overly soft sounding cable.
All this is just my feeble theorising of what I think I hear, and just my opinion of course. One day, our experimentation in this area may bear fruit.
