What is the difference between 2 Conductor Vs. 4 Conductor Speaker Wire?

The 4 conductor wire is for biwiring and biamping speakers. The Standard speaker has two connections for accepting wire, while these have 4, one for positive and negative like regular speakers, and two others for the highs and lows, or for certain ranges of frequencies. Biamping is more functional then biwiring. The basic idea being more wires is that the more conductors, the less signals traveling on a single wire, which means less cross talk.