Not sure about for speaker applications, but it is interesting this has come up. While doing some yard work yesterday I noticed the ground wire going from one copper grounding rod to the other was dirty and not making a good connection. I decided to go to Home Depot and get the thickest wire I could find and make a new connection. I brought home a 2 guage copper stranded wire and hooked it up. My system sounded terrible. Back to HD and this time bought a 8 guage, hooked it up, and everything snapped back into the way it was before I changed anything....which is good. Then I got to thinking I had an extra set of Speltz cables around and what would happen if I used them to tie the copper rods together?? First I tried one run, then I doubled it for even better results, and now have a quadruple run of the Speltz cable tying the two copper rods together. Turned out to be an excellent tweak!