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I built this Bass cannon, based on the Bose WaveCanon. Its a resonating tube driven by an internal sub woofer.
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.
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.
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Signing UpStep 1Ingredients
Materials;
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
wood screws
glue / sealant (sikaflex works well)
Tools;
Router
Circle cutting jig for router
3/4" spade bit
Drill
circular saw or jig saw.
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
wood screws
glue / sealant (sikaflex works well)
Tools;
Router
Circle cutting jig for router
3/4" spade bit
Drill
circular saw or jig saw.
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Have fun!
However, in testing it appears to resonate well over a very wide range of frequencies which I suppose is sort of a good thing for music and films but It makes it really difficult to understand :(
Then I wrapped a small piece of card around the speaker to hold it in position and added a large pile of nail polish to protect the connections from shorts and to glue the speaker in place (not completely necessary but it makes it secure.)
Finally, I took a thickish sheet of paper and found where 1/4 of the way along its edge was. Taped the speaker tube so it was roughly centred on the line and rolled the paper into a tube. You can hear the change in volume from bare speaker to speaker in tube if you're playing music/ a tone through it when you roll it up.
You can run the wire through the tube by poking holes in it and putting the wire through them as you roll up the paper or just run the connection out of the bottom.
There are three quickly and pooly taken pictures included to roughly show what I did with the first being of the speaker in the cardboard tube, the second is sort of it being taped 1/4 of the way along the papers edge and the last of the completed thing, the speaker is roughly where my hand is.
my friend and i are building our own bass cannon. are there any suggestions your can make to help us? we would like our frequency to be about 20hz.. more bassy.
anyway, do you remember what equation you used to tune it? that would be very helpful.
oh, im using a 2000 watt lanzar 15" driver, dual 4 ohm coils, and a crown cdi 1000 watt amp, probably being bridge mono at 4 ohms, (1400 watt)
thanks!
Great job though... I've always wanted to make one if these... since at least 1989 (they had two of these at my college student center auditorium)... they even have one at the Local Fry's Electronics mounted hanging from the ceiling under a suspended projector screen....
shame you guys are not metric
... or i am not standard
nice instructable in any case
17Hz , 31Hz , 41Hz , 55Hz , 73Hz , 98Hz
Fast Ed
1) how much did this cost?
2) how did oyu make the circular light at the top?
The opposite, actually, so a long tube gets lower...
"I figured my resonant frequency was about 30Hz."
Speed of sound (13400 inches/second) divided by (12 feet x 12 inches) = 93Hz. A resonances will be exited at 23Hz (1/4 of 93, but not at 1/2 of 93 where it will tend to cancel a little). A fast slope lowpass at 40Hz will get rid of the fundamental at 93Hz, leaving only the eye openning spike at 23Hz. Enough amplification will classify this as earthmoving equipment. Use of polyfill or fiberglass insulation in the pipe (unknown quantity and position TBD by experimentation) will actually allow use for music by smoothing spikes at the cost of some output.
I just re-read, and your positioning of the speaker at three feet down is a copy of a BOSE design. The placement is an attempt to make the speaker more musical and less peaky in output near the 1/4 wave resonance. IIRC, the BOSE system needed extensive equalization to sound acceptable, and is more gimmicky than practical. At any rate, I'm sure you got huge output at a low frequency (31Hz?).
Diameter multiplyed by length will affect tuning if that total volume is much too small to support the Vas parameter of the speaker. The Fs of the driver will have an impact as well, but both of these parameters are mostly negligible at very large scales such as this. Qms, Fs and Bl factor taken together produce a rating called "mass corner" (I forget the formula) and would be the governing factor in low frequency output if this speaker were just simply placed on a very large panel with no tunnel on either end.
The travel of the subwoofer is equal in each direction so you get equal sound in each direction.
Steve000 here may not have considered that your experience here may be limited due to your age.. Omega13Shadow - does that mean your perhaps a teenager? "13"
Message me if you want any tips or have any questions.
This above prevents me from saying what i really want to say about this question. Google is your friend, Basically get wire, connect to AMP power amp, connect a audio source to amp, play audio source, sound is AMPLIFIED and travels through the wires to the SUB, and makes sound.
How to wire from sub inside tube, I dunno, maybe a small hole in the side of the tube, with wire running out and sealed up with silicon or somthing.
An AMP like 1 from a car will need a 12volt source of Positive and Negative, power cables needs to be around 4ga for a moderate amp. SUb wires need a min of 8ga wire.
what more is there to say
I knew how to wire up audio and install loooooong before actually doing it, again google is a wonderful good friend of everyone with the internet
This one sold me on sketchup..
http://fle33.com/content/?p=110
After I was able to re create almost exactly what sketchup had modeled I was very impressed. For a backyard tinkerer like me I don't require industrial modeling software.
Thanks for the tip anyway.