Do speaker cables really make a difference ?

They definitely do and probably more than any other cable, then power cables, interconnects and digital cables the least. At least that’s my opinion. If you can’t hear the difference in your system then you should probably start with upgrading your speakers first.

Just purchased a pair of Nordost Frey 2’s which replaced, still have, WyWires Silver Series. First the WyWires are wonderful cables that throw a huge stage and the first speaker cables I’ve owned that made my speakers disappear.  
 

Well, as good as the WyWires are, which mine are three series down from Alex’s best are nowhere close to the Frey 2. More everything, hearing micro details in recordings I have known for years and great recordings sound like the performers are in my room, average and some not so great recordings sound better. The upgrade was like getting a speaker upgrade, not subtle.

Yes, speaker cables make a difference, and I’ll stick to my earlier comment that speaker cables in my opinion can make the biggest or most noticeable difference between cables. Yes, there is a significant cost difference between these speaker cables, and the difference is there.