i have a single zv4 15 with a box i made. its 5 cubs with a 8 in external aero and im running a vfl 400.1 to the sub a 1 ohm. it pounds but idk if its to big. its tuned to around 33 hz. i feel like it could maybe be a little louder but idk. i know most people do 4 to 4.5 cubs for this sub but...