Some folks on this forum might want to read measurements of different cables affecting sound. They do, and like anything in audio, especially in the boutique world or the garage con artists,
if you screw something up enough you will get results.... document page 39 is where it starts for those who need to learn more about cables. The contrary to the above underlined is if you perfect something enough it is no longer
audibly improved....
http://www.biline.ca/audio_critic/mags/The_Audio_Critic_16_r.pdf
Thank you. Since reading that, as I did way back when, I have been a believer in short, hi gauge (low R) speaker cables preferably also with low inductance (L), and, of course, no exotic metals or winding geometry, or flat ribbons, or built-in networks, etc. I cannot measure or model myself, but I think that has kept me out of trouble, and it has saved me a bundle of otherwise wasted money. Not hard to do, as long as the manufacturer provides basic LRC electrical specs. If he doesn't, look elsewhere.
For interconnects, short is also good, but if you must go long, balanced XLR is the way to do it, preferably with low capacitance (C), as in pro mic cable, but not "audiophile" stuff.
Of course, tube gear throws a monkey wrench into all this with its own special loading characteristics and consequently larger response deviations, making cables a clumsy, inflexible choice of effectively tone controls with that gear.