System build questions

[escottl92]

Hello i have a 4door f150, i took out back and put a 13cu ported box in.  I sound deadened roof, wall and all doors.  I have a 320amp alt, agm under hood second battery in back.  Right now i have 2 18" Fi Team 4 subs on an ampere 7.5K.  Im doing a 151 in passenger seat ( Meca) I bough another battery and second amp, my question is does anyone have any advise on how i can get more db?? I dont want a wall box.  

Thanks

[CrackFactory]

More subs and more power. Maybe a blow through??

[SnowDrifter]

Getting loud is a rather scientific venture. Test box design, placement, port tuning and area (good place to start), wiring loads, seat positions, etc. Take a variable, any variable, and start playing with it. Even turning the ac or heat on/off to mess with air density can have an effect

[escottl92]

Thanks for advice