warmest speaker cables you've heard?

You want cables that are neutral. If you have overly bright speakers then maybe buy a warmer sounding speaker such as a British made speaker, wharfedale, tannoy, spendor, harbeth, etc..  

i appreciate the good intentions! really, i do.

again, the speaker cables i need are for hooking up to the following item:
https://raalrequisite.com/product/ribbon-amp-interface/

which in turn hooks up to:
https://raalrequisite.com/product/sr1a-earfield-monitors/

You want cables that are neutral.

Why? Is there some kind of "audiophile" rule that we need to comply by?

If you have overly bright speakers then maybe buy a warmer sounding speaker such as a British made speaker, wharfedale, tannoy, spendor, harbeth, etc..

Ok, so rather than swapping out cables to solve a possible brightness issue that would cost him $500 - $1,000 to change, you suggest swapping out speakers that may cost $1,000 - $10,000 or even more to change?

Not an economically prudent approach.

I was using Monster Power Line 3 cables.  But I noticed a big difference when I auditioned Vampire Wire continuous cast copper.  I ran them between to KEF Reference 104.2 speakers and an Onkyo Integra M 504 amp. 

I guess the idea is they can stretch the copper crystals to be up to 20+ feet long so that on a short run, you are never going through more than two copper crystals at a time.  

When friends came over I would do a blind A/B/A/B type demonstration and each person could tell a difference and preferred the Vampire Wire to the Monster Power Line 3 cables. 

Even  people who did not care much about Hi-Fi preferred the sound with the Vampire Wire cables.  

I don't know how these would compare to the cables you mentioned but, for me they definitely warmed up the sound.  I had tighter bass and smoother midrange and treble.  

My question is why would you want "warm" speaker cables? Don't you want accuracy? If you want warm sound, just turn the treble tone control down or use an EQ.