An amp doubles your wattage when u drop the omhs, but the subwoofer can take less wattage when run at an lower omhs. if there is a 1000 watt 4 ohm voice coil, then when wired to 2 ohms, it can take 500 omhs, when wired down to 1 ohm, it can only take 250 watts @ 1 ohm. A 500 rms wattage sub...