Here's why biwiring works...
For those who know a bit about the different video cables (stay with me!), the worst is composite. That's because the color and luminance signals have to travel together down the one cable and interfere with each other. Once you separate them (S-video), the difference is very visible.
Likewise with speaker cable, the full range of frequencies must travel together the full length of the cable, which may be several metres long. They are then only split by the the low & high pass filters once they reach the speaker.
Now with biwiring, the amp doesn't "know" which cable to send the highs and lows down. But what happens is this: the cable to the tweeter is connected to a high pass filter in the speaker, which means the amp sees a continuous circuit for high frequencies, but very high resistance to lows - virtually an open circuit - and so no lows can travel along that cable. Likewise, the bass cable connects to a low pass (or high cut) filter which blocks high frequencies, thus preventing high frequencies from traveling through that circuit. This split occurs at the speaker terminals and means the low and high frequencies don't interfere with each other as they travel to the speaker.
Now, how audible this difference is, or the merits of using different metals for conductors, is another argument altogether! I haven't tested it, but my guess would be that over short runs with good cable, it's probably only very very slight.
For those who know a bit about the different video cables (stay with me!), the worst is composite. That's because the color and luminance signals have to travel together down the one cable and interfere with each other. Once you separate them (S-video), the difference is very visible.
Likewise with speaker cable, the full range of frequencies must travel together the full length of the cable, which may be several metres long. They are then only split by the the low & high pass filters once they reach the speaker.
Now with biwiring, the amp doesn't "know" which cable to send the highs and lows down. But what happens is this: the cable to the tweeter is connected to a high pass filter in the speaker, which means the amp sees a continuous circuit for high frequencies, but very high resistance to lows - virtually an open circuit - and so no lows can travel along that cable. Likewise, the bass cable connects to a low pass (or high cut) filter which blocks high frequencies, thus preventing high frequencies from traveling through that circuit. This split occurs at the speaker terminals and means the low and high frequencies don't interfere with each other as they travel to the speaker.
Now, how audible this difference is, or the merits of using different metals for conductors, is another argument altogether! I haven't tested it, but my guess would be that over short runs with good cable, it's probably only very very slight.