I have been reading up a bit on cable as I will be experimenting with DIY IC's with a friend. It seems to be common knowledge that the signal not only passes through the wire but along its surface as well (in a different manner which is called "skin effect"). The sound is also influenced by the type of insulation(s) being used and how the insulation(s) meets (or does not meet as with an "air" surround) the wire. Impurities "in" wire may just be another obstacle for the signal to overcome (this is not saying that there cannot be "specific" impurities that would actually improve the sound). An example of this would seem to be silver oxide forming on silver cable based on the observations of others. Why limit it to just this? The types of connections and connectors used influence the sound (this I have already observed with a few DIY IC's). Also, getting back to "skin effect", how the surface of the wire is formed and finished should also have an influence as well. There is a lot to study and experiment with (and many different design features to take into consideration) if one keeps an open mind as well as an open ear(s). I consider the projects to be a fun and inexpensive ventures. As with most everything, it all depends on your outlook.
