Dave is echoing what I said about dielectrics. There are a number of cable makers that have addressed that concern. The Anti-Cable, a cable I championed, is very good in regards to noise suppression.
The mids of round solid wire are fine, but the highs are rolled off. That affects the mids as well making them overly warm. A very thin flat cable, if kept short, opens the highs significantly, significantly changing the overall character of some music.