Looking for a speaker cable with a relaxed sound.

Not answering your question, but I assume you've played with toe in and tilt to see if you can achieve a better balance?

This is the problem with speakers that aren't custom tuned to your ears.

Just kidding.  :)

Depending on your price range (and contradicting the posts above),
Wireworld Platinum Eclipse 7 speaker cables are the most relaxed, least bright cables I've ever heard and they're all silver. 
That model is at least 50% off of original prices, if not greater.

So you’ve all this detail and spent a bunch extracting it. Now you want to dull it back down a little? Try this experiment. Romex 14/2. The white one from Lowes/Depot. Use only the black and white wires.

Depends on your budget...there are some good choices
I would try ’Sorvelis’...their entry setup....talking about relaxed...Schubert sonatas went from relaxed to ultra relaxed on my floor standers by BMC

Did you get those speakers? If so , what were you using before?