4 leads?

[triune]

forgive teh ignorance...

but why do each of the speakers have four leads (connectors) ? The way you have them wired is intriguing.

I would guess that each has in input for seperate left and right channels, and they are mixed before outputting. This would make the ground common on both channels?

i'm probable totally off....

[ThomasW]

Originally developed for car audio, some drivers we use have two voice coils, that's means 2 (+) and 2 (-) wires.