Hey there, I would like some help with dimensions for a box for my SP4 18 subwoofer. The SP4 18 will be powered by a crescendo 3500D. I only have very limited space inside my trunk, but I want a ported box in every case and I want it tuned to 34 Hz. The maximum dimensions are: Width: 86 centimeters Depth: 47 centimeters Height: 65cm (I want to stay at max of 60 centimeters if possible) greetings