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

it isn't that extreme, thanks for the suggestion.  

Monk anybody?

@simonmoon  "  He likes those porcelain ceramic insulators. They can be found for a lot less money than the ones made for audio."

Isn't this a bit of a tip that some audio vendors can be quite predatory?
Also, I am suspicious of any tweak that is reported to take a few days or weeks to deliver it's benefits. That makes A-B comparisons extremely unreliable and magnifies the probability of user bias developing. 

This concept is the epitome of snake oil, confirmed by GK's embrace of it.  Try it it with styrofoam cups or empty rolls of toilet tissue for an experiment.  Trust your ears and watch your pocketbooks, that is my best advice, or you might be apt to buy goofy crystals thinking it will enhance the sound of your system.  Too funny.