Quoted from xizor:
I just made a cable using alligator clips and a single RCA male cable.
Cut off one end of RCA cable, there is an insulated wire (+) and a bare wire (-). Strip RCA cable so you can soldier an alligator clip to each.
Add heat shrink to both cables, soldier each alligator clip to both (+) and (-) of the RCA cable. Use a multimeter to continuity test to make sure it works as expected.
Then hook the alligator clips up to the woofer in the bottom of cabinet. The (-) goes to the Yellow/Black wire on woofer. (+) to Yellow.
Run wire through holes in back of cabinet to sub.
I do mine the same way. Quick and easy.