Does raising speaker cables off the floor really make a big difference?

There it is! Blind testing raises its ugly head, again. Not much of a surprise, you know, with all these Ethans running around rampant. 😬

It's a relatively cheap tweak to try out for yourself. Just get a Jenga set at a garage sale or cut a 1x2 furring strip into 2" lengths.

you dont know high end sound without cable risers.

mwhahaha

The best cable riser demonstration was at a show several years ago, perhaps RMAF. As I entered the room the demonstrator was using a foam-ish cable riser, I believe of Shunyata make, and rubbing it against the top of a CD. It was being used as an anti-static device. It worked to some degree, better than as a cable riser. 

Want to test this essentially for free?
Cardboard egg cartons. Cardboard is a great insulator for this application.
Cut each carton (discard the lid) into 4 equal sections. That gives you 3 egg holders per section.
Note the shape of your pieces, they even have ready made seating notches for your cables!