In EE 101 we learned that two identical resistances in parallel create a resistance of one half the amount. That is because the current flow divides half into each wire. R in parallel with R equals .5R. Total current flow of course is determined primarily by the impedance of the speaker. Voltage drop across the wires from end to end will drop to about half what it was with one wire.

My early EE courses were over 40 years ago; but I do think the basics still hold.