I need to know the dimensions for a sealed box for 2-ALPINE SWR-1242D 12" subs.... I am dumb when it comes to figuring that stuff out ..i have a 1400 watt amp ...putting about 600 RMS to each sub ..so i dunno.. if anyone can figure it out and tell me the dimensions that would be awsome because i really am lost when it comes to that..thanks a lot ..