For my $.02, I have a set of DIY 13 gauge, 4 conductor cables from Parts Express, marketed as speaker cable. The gold plated banana connectors are soldered on with silver solder. They're bi-wire, but only to eliminate the bridge connector between the binding posts. They don't sound remarkable, they carry a signal to the speakers.
I have a set of Kimber 8TC speaker cables, same length as the PE cables. In comparison, the PE cables sound like the signal goes through a layer of gauze. The Kimbers are clearer, cleaner, more detailed, and present a more open and coherent soundstage. Sure, a $600 pair of cables should sound better than a $20 pair of cables. And they do-in my rig, in my room. Whether or not a stranger on the internet agrees with me is irrelevant. Two of my uncles were engineers so I take them with a grain of salt. One uncle insists I should get Bose Cubes and an Acoustimess because "It sounds just as good". He's never heard my stereo. So being an engineer in no way makes one the final authority on anything-and frequently gets in the way of actually learning something.