A Real Sub

[Bill F.]

On my list of wannadoos when I build a listening room is a 8" false floor bass horn.

It would be pretty easy to do:
First, build a top-loading rear chamber box in a rear corner. On your subfloor, glue down 2x8s on edge defining your chosen expansion contour ending at a grated slit the full length of your front wall. The 90-deg. wall-floor angle of the front of your room will be the final flare. Put down short 2x8 pieces axially aligned at intervals throughout the horn flare (to support your flooring sheets), liberally glue/seal the whole thing, and put down flooring.

Now you've got a 20Hz bass horn, invisible except for the fact that you're ceiling is 10" nearer!

Bill