By far and away the best I’ve tried are Lenehan Audio FoiFlex cables which use a roughly 2" wide lacquered copper foil. Never have I used a more detailed and nuanced cable, yet it’s also utterly natural sounding with deep solid sounding accurate bass. Timbres seem to be more accurate than my previous cable choices also. I’m now running the FoilFlex RCA’s and speaker cables. I’d go as far as to say they’ve made the most significant improvement of any component in my sound chain which was rather unexpected.
FoilFlex - High quality hand made audio cables. – Foil Flex (foilflexcables.com)