Assuming I had two 200RMS/400MAX wattage subs, both four-ohm single voice coil... If I were to run them in parallel to achieve 2 ohms, how much wattage could they take when combined? What is the equation for figuring combined wattage on parallel configurations? I can't find it anywhere else... are the wattages from each speaker just added, or is there something bigger that I'm missing? Thanks