came up with my own design!

[wafsman 10+ year member]

how do i go about doing that?

 

[DNick454 10+ year member]

Yeah, if you took an enclosure made for two 12's and crammed another two in there, it's going to have too small of a net volume per sub and not nearly enough port to let all 4 12's breathe and most likely, the tuning will end up quite a bit higher than your original intended frequency range. I design boxes actually if you need something worked up. Just send me a PM with the kind of equipment you have to work with as well as the maximum dimension your trunk can fit or atleast what you're willing to give up in your trunk.