rear soeaker wire +/_ color ??

i have blue and blue with a dark blue line on one side, and yellow and yellow with a black line for the rear speker wires. does anyone know which is positive and which is negative for these?? thanks.

I'm not positive about this because I used 16 ga from my Alpine amp but my guess would be is the yellow is positive and yellow/black is neg. and blue is pos and blue with dark blue is neg...Try it, set the fader to the rear, then mess with the balance. If there is more bass when just one speaker is playing, then you have to switch just ONE of the speaker polarities.