Box for 2 Alpine Type X's

[Rickdod3]

Hey Guys im pretty new to the forum, This is my first post actually, ive read alot on here tho, anyway...Me and my good friend have started working on a project car and at the moment this is what we got...

220amp Iraggi Alt.

Kinetik HC1800

1/0 Wire with The big 3

2 Hifonics Brutus BXI2010D

and 2 alpine 12" Type x's

Right now they are in a custom ported box, im not sure exactly what it is tuned to but im pretty sure they guy that we had build it said 35hz... I was wondering what would be the best box to have these subs in, they reall pound as it is but im almost sure it could be louder. Its in a ford explorer so we have alot of room too. Thanks!