Basically a Giant Sub Woofer.
I built this as part of an audio visual project for Burning Man 2007. Using a tube with the driver mounted inside it resonates much like a church pipe organ within a specific frequency range. Hopefully the bass frequency range.
Called "Rare Angles" it comprises 12' of cardboard Sonotube as used by concreters to form columns. Its cheap, easy to work with and rigid enough to use for this application. You can get it at a concrete supplier.
As soon as I laid eyes on what Holly and team over at positron.org did, I knew it was just a matter of time, and any flimsy excuse to build my own.
This Bass Cannon is designed very basically. I was able to buy a 12' length of 16" sonotube. The driver has to be placed exactly 1/4 the distance down the full length of the tube or 3 feet.
From what I can gather from research, the longer the tube length will raise your resonant frequency. I figured my resonant frequency was about 30Hz. I am probably wrong. I did the calc a while ago so can't be sure how I arrived there.. It wasn't too loud on the "test fire" audio sweep, but a neighbour from 2 doors down, certainly heard it and came running down the street.. "Are you making that noise?!"
Maybe me sitting on my deck with a giant carboard tube and earmuffs on gave me away.
Step 1: Ingredients
1 x sub woofer 12 or 15" depending on the sise of tube you want 15" in this case
1 x length of sonotube slightly larger than your sub woofer diameter 16" in this case
1 x sheet of 3/4" ply
glue / sealant (sikaflex works well)
Circle cutting jig for router
3/4" spade bit
circular saw or jig saw.