Bought two of the aura pro bass shakers, should I wire these two in a series or wire them in seperate channels. I'm still deciding on whether I'm going to add two more down the road. I have an old pioneer 390 watt 8 ohm receiver that I'm using as an amp. Just wanted to make sure they shake equally and I don't destroy anything. Last noob question, the old pioneer has equalizer settings what should these be set on?