Hey everyone I recently got a Alpine mrp-m500 amp to match and power my 12" Eclipse SW8122DVC sub but anyways...i was setting the gain to the amp while using a multimeter trying to reach rhe 31.6v for 500w rms @ 2ohms and it would read low ac volts maxed out and only got to the number by turning up the bass eq up quite a bit. My headunit has 4v preouts and the alpine amp has a max of 4v so do i just max out the gain?