Can anyone explain my KENWOOD AMP to me?

I just installed my brand new Kenwood KAC-7205 amp and hooked it up to a single 12" CVR DVC 2ohm sub. the amp is bridged and should be making 500W x 1ch. @ 4ohms. Wired in series due to the dual 2 CVR. But would TWO single voice coil 4ohm subs be a better choice? Also I think it should hit hard than it does and was wondering about the settings. the LPF is actually "OFF" at the moment because it hits harder without it. I know.... i agree....It dosent make any scents. The bass boost level is at about 3 but will go to 18 With a drop in sound quality and distortion the higher you push it. The head unit is a Alpine CDE-100. So...two subs or one? and alittle info on how to set the bass boost, Input Sensitivity, and LPF switch and variable knob would be like gold to me right now. Thanks again for any info or advice. Rob.