Nsgarch, once again, I see that you think that signal current flows only in one direction or that the polarity of a signal doesn't change. Actually a signal at 100Hz changes polarity 100 times in one second. If it didn't, how would you expect the speaker to work. In fact to check for polarity of a speaker, one applies a DC voltage (of a given polarity) to the speaker terminals and notes which direction the speaker cone goes. To get the cone to go in the other direction, one must reverse the polarity. If one wants the speaker to respond to a signal of a frequency of 100hz, then I guess that the signal must reverse polariy 100 times a second. The current, of course, during all this polariy switching, reverses direction as many times. Kind of renders direction of current in cables and direction of speaker cables, silly, don't you think?
Bob P.