sdl4 - thanks for the tip; I hadn't seen them in the video. Cardas is a finalist in my hookup wire trials for Renaissance Upgrades. I'll be reporting in a couple of weeks.
Can confirm that Cardas Audio has a pair of 3.7 although I don’t know if that’s the main speaker in their listening room. The person I spoke with was interested in my upgrade project and wants to be alerted to any upgrades that become available for the 3.7.
Cardas hookup wire and binding posts were my final changes (and, perhaps, most extravagant expense). It was the icing on the cake, kinda snapped the sonic picture into a cohesive and clear soundscape.
I used Cardas “chassis wire”. These are Litz stranded and ends *must* be tinned in a solder pot. Cardas can do this but they charge something like $5 per end - ouch! So, I bought a cheap solder pot. My entire project used Cardas solder (which is leaded, I did all soldering outdoors or in my greenhouse). Woofer input is Cardas 15 ga + 17.5 ga (effective 14 ga), output to woofer is 15 ga. Coax input is Cardas15 ga, output to coax is 17.5 ga.