They make a huge differen$e! These are the cables I use for my Yamaha center speaker:
Speakz D-TC SUPREME Speaker Cable World-class performer in signal transmission The Ansuz Speakz D-TC Supreme is the ultimate speaker cable. Equipped with Ansuz most sophisticated and most advanced noise reduction and resonance control this cable is a world-class, top-of-the-line signal cable...
houseofstereo.com
View attachment 498721
These are not overpriced at $70,000.00 a pair, considering that they make the sound warm, rich, and holographic, in a way no other cable can. Try it for yourself and hear the results. I promise you won't be disappointed!
Seriously though, stereo is still better than mono, that's why they switched over to stereo in the late 50's. The reason I use mono is to fill in the lost vocals from my Hafler circuit setup that happens with stereo recordings sometimes, and I need my mono speaker to be turned up at least as much as the L/R. I do enjoy the center mono speaker experience and may use it on its own occasionally.