Oh this debate ran and ran, and the wre was something about somebody offering a zillion squid if anybody could tell the difference between cable x and cable Y in a blind test and la de da...
Hi-Fi like many things has snake oil salesmen and smoke and mirrors and suffers hugely from the laws of diminishing returns. However, I'll be bold and say that speaker cables (and other cabling) does have an impact on sound quality, but up to a point, and that point is reached fairly quickly in terms of expenditure.
It's easy and cheap to experiment to see if there
are differences with different cables, buy some solid core mains wire from your local B&Q, the biggest diameter that'll fit your speakers and some cheap bell wire.
Can you tell a difference between them?
I've played around quite a bit with this...
I also know that you can buy expensive cables that make your Hi-Fi sound worst than cheap cable too.