Contrary to most of the other opinions here, I say biwire works. It's easy to tell the difference if you biwire one speaker and don't the other. Can A/B just by walking from one to the other. Using Martin Logan Request which are highly resolving and Audioquest Type 8 splitting one cable's wires (has 8 conductors) to biwire and leaving the other cable intact, it was eminently obvious that all the components of the program on the biwire side had better separation and clarity. When high and low frequency travels on the same wire the bass energy distorts the treble energy. Biwire eliminates that problem. As usual it's a matter of everyone can say otherwise but I heard it easily for myself so I can not be convinced otherwise. It's exactly the "cables don't make a difference" argument. All you can do is feel sorry for the people who can't hear it.
Single vs Bi-wire Speaker Cable
I'm going to purchase some AQ speaker cables, and am considering bi-wired AQ Robin Hood Zero vs full range William Tell Zero (with quality jumpers). The bi-wired RH is about $500 more expensive than the full range WT, but on a comparable basis, WT is the more expensive cable. Any thoughts on sound quality between the options I described above would be greatly appreciated.