I NEED THE BEST 6FT3 ENCLOSURE SPECS THAT CAN BE BUILT FOR A SOLO X 12.?

-DEAR ALL YOUR HELP WOULD BE HIGHLY APPRECIATED IN ABOVE REGARDS, I HAVE SPENT ALMOST A MONTH IN BUILDING A BOX OF 6FT3 AS PER KICKER RECOMENDATIONS IN THE MANUAL, THE BOX IS 6FT3 FOR SUV'S AS CATEGORIZED BY THEM & FURTHER SPECS ARE PORT LENTH 6 " PORT AREA 60 IN ^2 & BOX TUNING FREQ IS 45 HZ.

I WAS PREVIOSLY USING 3FT3 BOX & THAT WAS LOUD BUT THIS ONE IS CRAP... I NEED HELP TO USE THE SAME BOX TO SOUND BETTER OR IF SOMEONE CAN PROVIDE ME BETTER SPECS FOR 6FT3 BOX