i have a 18" RD Audio HW Dual 2 ohm 3000/6000watts
i plan on building a box to 5.5 cubes tuned around
34 or 36 HZ and i was wanting to do llike an aero port
using concret tubes lol
i want to use two ports can anyone help me or give me a better ideal

like this its 12"x 48 for like 12$ Shop Sakrete 12" x 48" Concrete Forming Tube at Lowes.com
or 10"x 48 Shop Sakrete 12" x 48" Concrete Forming Tube at Lowes.com