Murrel said:
go here
http://melhuish.org/audio/index.html these guys will help you. Enjoy the sight there are lots of DIY ideas and lots of pics of some crazy speakers!
Murre
Yeah, single speaker system really sound excellent if you don't miss your hot highs and powerful bass.
With some work you can get it to sound as good as a table top tube radio!
Peavey makes a line of folded horn subs, but the focus is more high output rather than uncolored bass. Also the bottom end is usually 60Hz. Typical PA speaker.
Kilpschorns "corner loaded" speaker can get down in the 30Hz range because they use a corner wall to enhance the bass.
Hmmmm, Plans for some Kilpschorns knockoffs would be in order.