Be forewarned that series wiring presents a completely different load on an amplifier and is not the usually recommended way to wire speakers. Just an FYI. Good luck.
Im just wiring up some bass shakers, and am using a old sony receiver to power 4 shakers.
I went from the + on the receiver to the + on a shaker then from the - on the same shaker went to the + on the next shaker and from the - of the 2nd shaker back to the - on the receiver. Repeated this for the other 2 shakers