Instructables

800watt, 12' long 16" diameter Bass Cannon.

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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.


 
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Step 1: Ingredients

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.
dante8026 made it!4 months ago

I started a DJ club about 4 years ago and we just finally got around to financing and building a Bass Cannon based on your design. We used a Peavey LowMax 4800 watt sub paired with a Behringer 6000 watt iNUKE am. We used a sonotube that is 20" diameter by 12 feet long. We suspended the whole thing on a rolling car with rope to prevent the cart from rattling. It is not at full power in this video and our other 2 18's are not hooked up. This is the Bass Cannon at about 30$. We were not allowed to turn it on during freshman orientation because of all the bass h8terz. Thank for your design post. The Cannon sounds amazing.

Here is the video of the Bass Cannon we built...

bpmBC.jpg

30% not 30$ BTW: all in all we spent about $1400 on this project.

Your Cannon (R.I.P.) was an example of true transmission line bass. I have a pair of DCM Time Frame 2000's connected to a mint condition Pioneer SX-1980. The bass is superbly tight. I cannot imagine what that Monster sounded like.

http://i168.photobucket.com/albums/u167/georgeandr...

jhuddleston3 years ago
i started reading about this last night, i was so amazed about it. So this morning i took a small surround speaker to see what i could make on a small scale. I used four foot of 2 1/2 in. pvc pipe, and i was blown away cause it hits and sounds just as good as my surround system sub woofer. I will defiantly have to go bigger and see what i can accomplish, i would like to thank you guys for all the info you have said here.
it's called a transmission line speaker, it's made to reduce the low end roll off that a lot of speaker cabinets will give to a loudspeaker, try quarter-wave dot com to learn more about them if you'd like.
Hogbroom11 months ago
So...can I play dubstep at the Talent Show this year with this thing, or is the frequency off?
shootermatic11 months ago
How heavy is it? I want to build one of these in the style of Arni's mini gun in predator so I can sneak around to my neighbours in the middle of the night and open up hell's gates.
epicnoobpwn12 months ago
Let the bass cannon kick it...
Hey how to you route something that isn't just a straight line? Sorry I'm 16 and only ever routed the odd housing joint so don't know how to do it on something circular
NastySpill (author)  JonnyDude20081 year ago
You use a quick circular routing jig, like this..
http://www.youtube.com/watch?v=TgVUfveD4y8
ah i see thanks :)
thelandlord5 years ago
There's an easy way to make people very ill without needing tubes big enough to resonate right down there... make two tubes, one tuned for about 20HZ, another for about 27HZ. Feed your stereo amplifier with the matching tones on each channel.

Aim them toe-in to make the 'beams' cross a safe distance away, and turn up the steam... where the two soundfronts meet, they'll beat against each other and that'll make two tones other than the ones you've put in... 20+27=47Hz, and 27-20=7Hz.

47Hz you will hear as a very loud hum, slightly flat of a mains hum.
7Hz, you will not hear at all (unless you're an elephant) however anybody unfortunate enough to encounter the 'sweet spot' will soon feel very poorly indeed as their internals begin to resonate - think extremely seasick, only so much worse - they'll pray for death to come quickly. :-)

If you have a bad neighbour, this could completely ruin their night. ;-)
Where do you learn to do this? "Sounds" interesting.
Originally, by spending too much time with 'musical theatre' types - there was a musical called 'Time' written by Dave Clark that was quite popular in the UK a while ago, and it used something similar as a special effect. They needed the audience to feel 'space-sick' during a rocket-launch, and clearly couldn't physically pick the auditorium up and shake it... so somebody had the idea of beating a 20Hz tone against a 17Hz one through the PA system... not loud enough to risk an 'accidental brown' if somebody was a little weak in that department (google 'Ben Folds' and 'Improv Everywhere' for one of the best pranks ever...) but enough to shake the room a bit and make everybody feel 'nervous' without quite understanding why. Of course, then you have to 'experiment', don't you? ;-)
I suppose you are talking about infrasonics... Look that up on this site, someone made a woofer that does it.
Improv Everywhere is awesome. I especially liked the mirror subway.
WAY more complicated than that. One minus the other and one plus the other is not what you end up with. You constructive and destructive interference, and a great deal of cancellation and diminished output. You'll get one modulated tone, not two seperate ones.
myth busters tested that its a myth.
didn't mythbusters do that one or was that for the other end ? can't remember now
Oh reeeeeeeeally? Any chance of an 'ible appearing? :3
I was always curious about the brown note...they said it was busted on mythbusters, but I dont 100% trust those guys. It's crazy neat either way.
Trust them or not, they've still got the best job in the world...
Yeah, pretty much!
clark frollard5 years ago
except thelandlord isn't talking about a brown note.
frollard clark5 years ago
hehe...seemed like it fit the bill...
Correct. :-)
ilpug2 years ago
That last picture is one of the cooler pictures I have ever seen. Awesome build!
seanhiebel2 years ago
Would it be possible to make this work at 4' long?
NastySpill (author)  seanhiebel2 years ago
Sure would! Just cut your tube so that the driver is 1' down the length. So you'll have a 1' section connected to a 3' section.

Have fun!
daliad1003 years ago
I have built a little one of these out of several sheets of paper, a small speaker and a dead pair of head phones and I must say it certainly works.

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 :(
you should post an instructable on how to make one such as you describe. i attempted putting headphones into a paper tube and it didn't do anything whatsoever. explain a little more?
I took a small speaker from an old toy and soldered it to the lead from the dead headphone so it had a 3.5mm jack for easy connectivity to sources of sound.

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.

P1050499.JPGP1050500.JPGP1050501.JPG
NastySpill (author)  daliad1002 years ago
So how did it work? Was the sound quality good?
NastySpill (author)  daliad1003 years ago
Thats Awesome!
Nicely done. i shall have to try that. thank you!
Let the Bass Cannon kick it!
hi there.
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!
total length of pipe = 1/4 of a complete wave length of the lowest Frequency you wish to produce cleanly/easily - so 20 cycles/second would divide the speed of sound in feet per second... to give you a single wave length, then divide by 4 to get pipe length... divide by 4 again to get the length of the short end and multiply that by 3 to get the long end... whee... loud and low.
akura23 years ago
Whenever I've seen the Bose Wave Cannon mounted, it's always been hanging from the ceiling horizontally... I think that having it stand vertically like this would affect the sound output negatively by creating pressure waves against the ground

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....
BAZOOKA BOOM BOOM YEA YEA
lobo0x74 years ago
inches... foots
shame you guys are not metric
... or i am not standard

nice instructable in any case
wrksnfx lobo0x74 years ago
12.7 mm = 1/2 inch X 24 half inches in 1 foot = 304.8mm
FastEd884 years ago
Now build 4 or 5 or 6  of them each tuned to the string resonace of a bass guitar and you could rock the neighborhood!

17Hz , 31Hz , 41Hz , 55Hz , 73Hz , 98Hz

Fast Ed
jibatsu4 years ago
do i simply wire this up to the subwoofer on my amp?
jibatsu jibatsu4 years ago
2 more things
1) how much did this cost?
2) how did oyu make the circular light at the top?
Is that Google Sketchup?
NastySpill (author)  GarbageMan5004 years ago
Yes it is. I never start anything these days without first modelling it in Sketchup. It has saved me countless hours and wasted time and materials. I recommend it. And its free.
Yeah. I tried Google Sketchup once, but i'm not very good with it.
NastySpill (author)  GarbageMan5004 years ago
I wasn't very good when I started, but now I can draw anything I dream up.. even this convoluted tension skin.. I impressed myself! It even ended up looking the same as the digital model.. youtube have tutorials on every aspect of sketchup.
NastySpill (author)  NastySpill4 years ago
i was trying to orbit in your pictures before i realised what i was doing.
Yeah. Thanks!
SolidWorks is a much better program, although not free. You can figure out ANYTHING about a project before designing it, including weight. I strongly recommend it.
NastySpill (author)  Omega13Shadow4 years ago
I'm yet to find a project that sketchup can't handle.

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.

fwater4 years ago
"the longer the tube length will raise your resonant frequency"

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?).
You can't multiply feet by inches and expect a meaningful result I'm afraid. Additionally, I do believe it's 12' by 16", not 12' by 12".
12 feet long multiplied by 12 inches in a foot gives the total length in inches.  The diameter has nothing to do (see below) with quarter wave resonance tuning, so I wasn't taking the diameter into account, just converting numbers.  If you wish, the speed of sound quoted at 13400 inches per second can be expressed as 1115 feet per second, divided by 12 feet, equalling 93Hz. 

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.
Does the orientation of the subwoofer have any effect on sound? Is it best to put it facing the shorter end or the longer end? 
NastySpill (author)  Omega13Shadow4 years ago
No that wont have any effect. I had it facing down, but in hindsight it should have been facing up, that way I could have run the wiring right up the inside of the lower half of the tube.
The travel of the subwoofer is equal in each direction so you get equal sound in each direction.
How do you wire the sub to the sound source, say, a guitar amplifier?
NastySpill (author)  Omega13Shadow4 years ago
I don't quite get your question.. Do you mean which wire goes where? Or do you mean I didn't explain how I wired it up to my amp?
Yea, how to wir it to the amp, I meant, although any wiring tips would help.
We have a "be nice" comment policy. Please be positive and constructive with your comments or risk being banned from our site

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
All right thanks, I'm not exactly a wiz at electricity but thank you for the advice
Also before any "Im sorry i have never done audio before like you therefor how am i supposed to know stuff"
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
NastySpill (author)  Omega13Shadow4 years ago

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.
ChicSpandex4 years ago
Actually, the concept is quite old, I believe from the 1800s. I don't remember what it's called. It was discovered that a grid of heated wire at the right place created a large sound at the resonant frequency of the tube.
ruffboy5 years ago
What made the rings of light? We make Sonotubes in Texas. If you will start marketing these canons it may help our business.
hey don't it will hurt the original designer! to make money out of his exact design!
BOSE is known as a company that will try to sue the sh*t out of anyone who publicly criticizes any of their designs or copies anything that they have produced. This particular arrangement is un-patentable because of it's standard arrangement, i.e., the Hemholz family can't sue anyone for producing a ported woofer cabinet. BOSE is a deplorable company for their misleading or outright untrue performance claims. Their cheap but expensive equipment and lousy performance vs. almost any competitor speaks for itself. Ask any speaker DIY'er.
Do you have audio footage of this?
NastySpill (author)  grinddrummer4 years ago
Unfortunately my video camera died right as I set it up..
Aw bummer!!! Awesome project!!!
peterlonz5 years ago
Fabulous project, breathtaking in concept & well executed. BUT you don't tell us here how you can practically use it. I would have expected that as it's a fixed frequency device ( resonce controlled) it's of interest only for making a huge mototonal noise. I can't see how pipe organ music could be enjoyed with such a device. More reporting of use please! Peter O
NastySpill (author)  peterlonz4 years ago
Hi Peter, In short its a sub woofer. Used in PA system Installations like any other bass bin enclosure. Using a suitable lowpass or bandpass filter it can come into effect only on frequencies it is suitable for.
is a bandpass or lowpass basically a low frequency crossover
NastySpill (author)  Da Nugesta4 years ago
A band pass filter lets a band of frequencies pass such as 300hz to 15,000 hz, which you might send to a midrange speaker. a low pass filter only passes low frequencies and a high pass only passes high frequencies.. Your right - a crossover is exactly that. A lowpass and a highpass.. so that the signal is split into two streams.
ok thanks
Spedy peterlonz4 years ago
I'm pretty sure it can produce many tones at multiples of the basic resonant frequency. 2x, 3x, 4x ect.. Anyway, very cool project. It's something I'd build if I had the patience/money/time :]
So...Where do the fish shoot out? Does it only work on bass or could you use trout as well?
NastySpill (author)  GwydTUnusual4 years ago
"I shoot fish, and I vote!"

As opposed to
"I shoot, fish, and I vote"
LOL Cheesy!
axiesdad5 years ago
Dumb question time. What does it do? I understand that it creates low frequency sound, but what's the point? Is it just loud? Does it shatter masonry walls? Cause convulsions or hallucinations? This is a very well done Instructable; I'm sure I could build one of these if I just knew why I would want to. Please help cure my ignorance.
NastySpill (author)  axiesdad4 years ago
Its just a sub woofer.. If you can fit one under your house you can have a great sound system!
yes great but not everyone has a basement! :-) xD LOL
0.775volts4 years ago
nice build! do you have measurements of your results?

this project remind me of "El Pipe-o", a similar subwoofer setup that uses 21" drivers.

the root site there has many audio-related projects if you feel like tinkering around.

http://www.passdiy.com/pdf/el-pipe-o.pdf
NastySpill (author)  0.775volts4 years ago
No I was under extreme time pressure to get this going.. It is pretty much the same ideas as el pipo. Lots of discussion on if these tuned pipes are all that great. They are loud... but mine sounded a bit rough due to its vertical stance.. I have spent lots of time in that web site..
peterlonz4 years ago
It's me again. There sure is a lot of interest in using this device for "neighbour retaliation". What do they put in the water over there? It's way too big to be subtle or to go un-noticed. I think what we all would like to know from the builder: 1) How to create the wonderful light ring display. 2) What can you practically use this thing for other than creating very loud resonant frequencies which are exact multiples of the main fundamental resonant frequency? 3) What would you use as a signal source to feed the woofer driver? Peter O
NastySpill (author)  peterlonz4 years ago
1. You can read up on the light display here; http://fle33.com/public/content/view/5/2/
2. Its a novel sub woofer.
3. Music. via a suitable low pass filter.

What is all the cool stuff in the background of the pic? Looks like an aluminum bridge...
NastySpill (author)  bigtreehouse4 years ago
Yeah it is a bridge. Its my assembly workshop - just joking.. I worked for a general engineering company at the time I built it. Used the place afterhours to make it.
pyroal5 years ago
that is awesome!!! where did you get the idea to buid it
NastySpill (author)  pyroal4 years ago
casey321b5 years ago
If you used bungie cords to suspend for even better sound would the pressure push it to the ground or would there be enough resistance from the cords to keep everything up?
NastySpill (author)  casey321b4 years ago
Ideal this would be mounted horizontally. The frequency (even 30hz) is too high to acheive any movement.
downeasta5 years ago
Wow! When I first saw it I thought how bad it would be to be your neighbor.. but after you added the spinning light organ even old cranky me had to admit that it is a very cool rig! I'd love to hear/see it. I'd try Saint-Saëns, Organ Symphony #3. (attached) The "16 foot stop" low notes would be just mind blowing if not metal bending! Please let me know if you try it. http://www.youtube.com/watch?v=0d0itDEs9uo
NastySpill (author)  downeasta4 years ago
Yes that would be special!! I don't what what the dity is called, but the dracula music would be my choice. The analogy I use is suitable here - a tuned pipe organ. They are deisnged to resonate at a specific frequency - same as my system, however mine becomes less efficient at neighbouring frequencies. Thanks.
the bottom part is a rocket :D great ible
barshterd5 years ago
Back in the day, we used to design and build speaker enclosures that similarly boosted the low frequency volume of a woofer. The design started out as basically a large tube, approximately the same diameter as the woofer we were using. As most know, a speaker produces sound by pushing air out when the cone moves forward and pulling the air back in when it moves backward. What many people don't realize is that the rear side of the speaker cone does exactly the same thing - except that the wave from the back side is exactly 180 degrees out of phase with the wave from the front. If you can delay the back wave just long enough, you can bring it into phase with the front wave thereby almost doubling the volume of the speaker. For a given, single frequency, this is pretty easy to do and pretty easy to calculate. Using 100 Hz as an example, we know that sound travels at ~1,100 ft/sec. So for 100 Hz, the sound wave completes one cycle (in/out, up/down, etc.) for every 11 feet that it travels. (the wavelength) Since we want to bring the back wave into step with the front wave, we want to delay the back wave by 1/2 of the wavelength or 5.5 feet. To do this, all we need is a tube that is 5.5 ft long and, better yet, ends up pointing the same direction as the front of the woofer. (think of the letter "U".) All speakers have a frequency at which they resonate naturally. (producing the loudest sound level for the amount of power that is driving them) Speaker manufacturers usually provide this number in the speaker's specifications. If all you want is a "LOUD," boomy speaker, design your tube length for this frequency. On the other hand, if you want a speaker with a louder, but smoother, low end performance, design your tube around 1/2 of the speaker's resonating frequency. This will help dampen the speaker's natural boominess at its resonating frequency while reinforcing (amplifying) the sound below and above the resonating frequency. Hence louder but smoother bass response overall. Because low frequency sound goes around bends and turns easily, you can feel free to bend the tube into all sorts of interesting shapes provided that the cross-sectional area of the tube remains the same and the end of the tube eventually aligns with the front of the woofer. Bending or folding the tube also gets rid of a lot of the higher frequency sound waves which we're not interested in and would be out of phase anyway. You can fill the tube with loosely packed fiberglass wool or cotton fiber to further reduce the high frequency noise, if you like. Incidentally, the tube doesn't have to be round or made from a length of sonotube - although sonotubes are really hard to beat. You can use any shaped tube made from wood or plastic for instance , but any flat and/or parallel surfaces will probably resonate at their own frequency thereby adding unwanted distortion to the sound produced. (I even recall people making their tubes out of concrete pipes or chimney tiles to avoid unwanted resonance.) Cheap and effective, but very heavy. In case someone asks, the correct name for a speaker enclosure of this design is "Acoustic Labyrinth." If you fold it as suggested here, then it is called a "Folded Acoustic Labyrinth" speaker enclosure. It's an old (1930's, I think) design but, if you think about it, there is one, very high-end, audio system manufacturer that still uses it today. Enjoy.
Car6on145 years ago
cool project. Landlord, would they have to be 180 out of phase to add or subtract? have any good links on how that works?
bears05 years ago
use audacity to increase the bass also then it would probably be ear piercing
teZca5 years ago
the last pic was amazing...
Ian015 years ago
If your tube is 12 feet long...

Given
l, length (m) = 12 ft = 3.6576 m
λ, wavelength (m). This is derived from the length.
v, speed of sound (m/s) = 340.29 m/s (at sea level and ~0°C, from Google)

Required
f, frequency (Hz or cycles/second)

Analysis
v = λf (wave formula)
f = v/λ

Also, λ is 4 times the length in this case, because there is a standing wave in a tube that is open at one end and closed at the other. There is a displacement antinode at the closed end (because it can’t move—I am ignoring the driver in favor of resonance) and a displacement node at the open end. The distance between a node and adjacent antinode is λ/4, or one quarter wavelength. Therefore, the length of the tube is ¼ wavelength, or the wavelength is 4 times the tube length.

Solution
f = (340.29 m/s)/λ
f = (340.29 m/s)/4l
f = (340.29 m/s)/4(3.6576 m)
f = 311.161176 m2/s
f = 311.161176 Hz
f ≅ 310 Hz

Paraphrase
A tube 12 feet or 3.7 m long will have a fundamental frequency of approximately 310 Hz, assuming the speed of sound is 340.29 m/s at sea level.

This, or course, will give a more accurate result if you put in a more accurate length. 310 Hz is the fundamental frequency of the tube. There are more frequencies (harmonic frequencies) that the tube can also resonate at. Their wavelengths will be 3λ/2, 5λ/2, 7λ/2, and so on. These frequencies result from the fact that there must be a displacement node (pressure antinode) at the closed end, and a displacement antinode (pressure node) at the open end.

(I just did this in Physics 20 class today.)
NastySpill (author)  Ian015 years ago
Thats magnificent!, But the tube is open at both ends, its freely vented. So how does this change the calculation? In my scribbings it changes the freq to 408Hz, which seems way off. I recall when I built this arriving at a figure like 27.8Hz.. can't for the life of me recall how.
NastySpill (author)  NastySpill5 years ago
Wait, now math has NEVER been a strong point for me, but your solution is borne from this equation...
f=340.29 m/s / (4 / L)
if I calc out your equation as written I get;
f= 340.29 m/s / (4* L)
f= 21.2 Hz

which is sub audible!
You're completely right.
What he did was:
((340.29 m/s)/4)*3.6576 m = 311.161176
When it should have been:
(340.29 m/s)/(4*3.6576 m) = 23.2591043
Which is what you did
Yes, but since you also get the harmonics, you also have 40, 80, etc. This thing rocks!!
A simple method I have used to mark exactly around the circumference of a cylinder is with a piece of paper longer than the circumference and at least 2" wide. Wrap around column and match up the nice straight, factory edge. Tape the strip together and either draw line against paper edge or spray paint the edge.
Awesome! I'd love to here that thing at full tilt! What music do you like to play through it?
covey125 years ago
is it illegal to put one on a car roof?
Thermionic5 years ago
Could something like this be aimed? I have a neighbor who loves to wake my three year old up at 1 in the morning with his hot rod. I would like to rattle his house with one of these!
NastySpill (author)  Thermionic5 years ago
You could, but it'd be incriminating.. It'd be quicker, cheaper, and have longer lasting effect to just report him to your relevant tax agency for tax evasion. No body expects nor enjoys a tax audit.
i kinda discovered this type of thing by accident when i put my sub into some old tires stacked it increased the power amazingly, especially when you put your head inside of the tires
theRIAA5 years ago
that is just freakin awesome! although I have to admit, at first I thought you could point this at people, evoking a solid wave of bass to cripple them to the ground...
jeff-o theRIAA5 years ago
Sure, but you'd need to lower the frequency to about 7Hz.
frollard jeff-o5 years ago
Still a couple hundred watts of directed energy can do damage even if it's not harmonic...
NastySpill (author)  theRIAA5 years ago
Yeah it was going to run that way, but it can do some damage without you really knowing it..
deemerch5 years ago
can you make a video and post it to youtube?
NastySpill (author)  deemerch5 years ago
A video of this thing running? as with many things at Burning Man it was consumed by fire.
robotkid2495 years ago
Haha, add a rocket to the bottom, and we're off to mars!
bowmaster5 years ago
The bottom part looks like a rocket.