box size, vehicle its going in, amps, electrical, what your llokin for(though i'm guessing SPL) you can't just throw those out there and expect a response
ok sorry i have 2 hifonics 2000 watt brutus it will be going in a 4 runner and i have done the big 3 and a yellow top so i want spl but also a daily driver or does anyone think that 2 18's would be louder than 4 15's i was just thinking that the 15's would have more surface area