how do I make a "sound cannon"?

Question

My daughter's 4th Year class is learning about sound waves and this was mentioned as an example.

Answer 1

Get a large hollow plastic tube, about 20cm or more diameter and about 30cm length. Stretch a balloonskin tightly over one end point at say a candle about 3-4m away and beat the skin sharply. A strong air pressure (sound wave) will be emitted and hopefully extinguish the candle. You could try building a 5m diameter one with a rubber sheet as the 'drum'. Pull back the membrane (requires considerable effort) and fire! Will apparently knock over objects including small people!

Answer 2

This device is similar to the popular noise cancelling technology found in personal headsets, pilot headsets, etc. The difference is that the device would modulate the output frequency and adaptively time the pulse to compound and amplify sound waves at their source. In layman's terms: you would point the canon at your target of choice....in this example an automobile driving through your neighborhood with a lot of obnoxious bass pounding from the trunk...you pull the trigger and send a pulse of the same exact frequency and amplitude, electronically timed so that it arrives just slightly before the pulse being emitted from the car and amplifies that sound exponentially. The resulting sound wave should generate enough compressive force to literally blow the windows out of the vehicle. Other uses could apply (see the following link to an already existing military example ->

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benjaminsbox, May 16 2006









I was hoping this would be a man of the cloth, in good health.

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UnaBubba, May 16 2006


It won't work for a lot of reasons. Especially not for bass--notice that the sound weapon in the (irrelevant) link emits high-pitched noise. Fishbone for flummery.

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baconbrain, May 16 2006


This deviced is definitely half baked, however I like where your headed with the idea. A possible variation would be an actual cannon ball with a sound proof shell. You would release an obsurd amount of decibells of sound waves into the hollow center enough that the dying noise would still be very loud on impact and fire. The problem with this approach is that the cannon ball would vibrate so much that it would crush your hands if handled.

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Phaedrus, Sep 13 2006


so the idea here is to use constructive interference to destroy a sound generating device?

1st question: //you pull the trigger and send a pulse of the same exact frequency and amplitude, electronically timed so that it arrives just slightly before the pulse being emitted from the car and amplifies that sound exponentially.// how do it know?

this assumes that the next bass note emitted will be exactly the same frequency and at a regular interval. also, it wouldnt amplify the sound exponentially it would simply be the addition of the 2 waves.if you sent a pulse of the samefrequency and amplitude and timed it just right, you would double the amplitude of the resultant wave.

2nd question: what is responsable for the timing?

if a car is moving through the neighborhood, you would have to first determine a distance from the car when the origional pulse was emmitted, then calculate delay from emission to reception by your device. then, calculate the speed of the car to compensate for the doppler effect on the pulse you observe. then calculate the distance and relative speed the car will be traveling when you fire the pulse and recompensate for both doppler effect and the lagtime of sound in air (about 343 m/s).




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Answer 3

a wrapping paper tube shows the effect ( concentrating the waves which effect the volume and pitch ) there is a cannon that fires 'sound' by using carbide gas to make an explosion and currently there are military weapons that concentrate and project sound

but at the age mentioned i would stick with the cardboard tube ( lol)

Answer 4

a wrapping paper tube shows the effect ( concentrating the waves which effect the volume and pitch ) there is a cannon that fires 'sound' by using carbide gas to make an explosion and currently there are military weapons that concentrate and project sound

but at the age mentioned i would stick with the cardboard tube ( lol )

Answer 5

Hi. This is pretty involved : http://www.forteantimes.com/articles/153_sonicweapons.shtml but Edmund Scientific used to have a small version for sale. : http://scientificsonline.com/product.asp_Q_pn_E_3081546 or http://scientificsonline.com/product.asp_Q_pn_E_3060466_A_cmc_E_CROSS_SELL_A_AirZooka