im very new to car audio and need help .i have the rockford 801s 2 channel amp and 2 12 inch kicker l5s . i see on the amp is the crossover frequency, the gain etc. . what should i set the crossover frequency to(70, 90 etc??)and the gain to get the most out of the subs and amp , i would like to have tight ,loud hard hitting bass without lots of distortion.