Max Townshend has long argued that the most important factor in a speaker cable is its geometry: the way the two conductors are arranged. This is more critical than the conductor and the insulation because the wrong geometry causes high frequency distortion that results in a hard, edgy sound that many have encountered in their quest to build the ultimate system.
In the white paper Townshend explains how to measure the effects that different geometries have on speaker cables and shows exactly what they do to the frequency response.