There are really two main reasons for 2 power and ground connections. The first reason is for current or amperage purposes. It allows the amp to draw more current without the possibility of overheating the wire. The second reason is to keep the price of wire down for the consumer. Running two 1/0 awg cables is alot cheaper than running one 4/0 awg cable. I am sure there are other reasons out there, but this is my belief and opinion. I need more info about your build. I need all your amp's size, model, and amperage; dsp's, crossover, or equalizer; and speaker's size, watts, and model. This is so I can tell you exactly how it can be set up.