Hi. I'm planning to build a folded horn sub to be loaded with an 18" driver. Anybody who has a plan or design of this kind of enclosure is truly appreciated. Thanks and more power.
You should concentrate your efforts in building a direct radiater box for that driver. It will be far more musical, sound better, be less expensive to build and go together a whole lot faster. There are lots of designs all over the internet for foldup up sub boxes. none of which sound any good in a home.