Looking for a speaker cable with a relaxed sound.

Wireworld Eclipse 8 would fit that bill.

What makes you so sure its the speakers that are the problem? Or more to the point, that laid back cables are the solution? Buying one thing with a problem trying to offset another thing with a problem has never seemed a good solution to me. Only thing worse is if you mis-identify the problem. So, why do you think this is the way to go?

Different time, different speakers, but I was experiencing your issues. I listened to some Belden 10 ga cable from Blue Jeans and it solved my issues to a T. And it is cheap to try first even if it doesn't work for you. 

To further @millercarbon's point, and although I suggested a cable that brings some qualities to the table, it's been my experience that you shouldn't try to fix sonic problems with cables.  Cables should enhance the qualities you already like about the components.  Any time I've tried to fix sonics with cables it was always just a long and costly exercise that inevitably precluded selling the offending component (speaker/amp/etc).