Not necessarily. You see it's the same electrically. The positives from the subs are touching the positive from the amp. No matter where along the wires you connect them to each other, it's the same. That diagram is exactly the same as connecting a wire from the + of the sub to the + of the amp on EACH sub and doing the same for negative. It was just easiest to draw by showing 1 wire coming from the amp and then 4 others branching off of it.