Yes, I meant AC in the general sense of the signal in the speaker cable having positive and negative voltages, not in the sense of a power cable. This was my point initially, that since the signal in the speaker wires is AC, revolving around zero volts, that it doesn't matter which way it's plugged in red-to-black and black-to-red or red-to-red and black-to-black.
Sorry, I don't think I'm describing this well. And full disclosure: my degree was in electrical engineering, so I ought to be able to be clearer. Like most engineers, I need to draw a diagram to explain my point, which doesn't work well on a forum like this.
I have a long weekend coming up. I'll see if I can repeat the experiment on my better system then. I've only put this off because my Audio Magic speaker wires are thick and unwieldy and my binding posts are so close together on my speakers that I have to be careful red doesn't touch black. (I'm not skeptical about the impact of zero impedance!)
