Speaker cable advice

AQ Type4, solid copper is what you seek.

My Harbeth C7s respond very well with a larger gauge copper,11 or 12 gauge rather than 14 or smaller. They sound fuller,warmer,and seem to have a bigger soundstage. I stumbled upon this trying two pairs of 13 g from amp to speakers. Any high quality copper with good connectors would be worth an audition.
The best I've found for my specific system (Aric Audio tube amp) are 11g ZenWave copper ribbons.
I'm also a big fan of Paul's(R.I.P.)Clear Days.

      What tvad and nonoise said, +1 (each)!      

       Improved conductivity does not cause colorations, or added brightness.

       What improved conductivity, dielectrics and construction methods SHOULD do, in any cable, is allow one to better hear what's either right or wrong, upstream.

There’s an 8ft pair of Acoustic Zen Satori cables on US AudioMart for only $350.  Grab’em — you’ll be thrilled. 

I have a pair of older hollowgram 2 ...another option.Full meal deal.