Here's a shot inside the cabinet to the Straight-Line Signal Path(TM) (SSP) crossover network. You can also see the gray-sheathed cable. It reads "JBL Optimum Performance Series(TM) Designed and Manufactured by Monster Cable(R) - Ultra High Purity Copper." I'd guess it to be 14Ga, but the sheathing is so thick it could be 16.