noise cancelling

[singularity]

alright this one just came to me i figure there is some reason why it wont work but im just gonna put it out there.

im not an expert on noise canceling headphones but from what i do know about them the produce a sound wave oppoosite to that of the background noise. causing only the music to be heard. alright now what if you were to scale that up, A LOT. thinking like 5.1 surround sound system now and you retrofitted a pair of head phones to the stereo. if you were to fire a rather loud cannon would the system cancel out the sound of the cannon. or would it at least dampen it enough the neighbors don't come out of their house wondering what that noise was?

i figure there is some huge reason this has never been done before that im overlooking but its a pain in the ass to run inside and hide whenever i fire this thing. o and the reason i dont want to put a silencer on it is because its a made to look like an AT-4 and a huge silencer sticking out the front will make it look stupid

[homedepotpro]

if what you say is true then there will be a constant loud mone from the noise canceling device EXCEPT when you shoot , it seems to create more problems then it solves.

[integral]

In theory you could record the sound produced from the cannon and through speakers you could emit a recording of the same sound with its polariy inverted so that both sound waves are in phase to cancle out the sound completely. However it would be very difficult achieving such a feat with our ordinary speakers and equiptment because of the requirements of producing a standing wave. Things like your speaker/mic response time in emitting the recording in phase with your cannon and the reverberation in your room would make the standing wave VERY hard to produce.

Your question alerted me to another possible use of noice cancelation. Wouldn't it be great if headphones cancel out the frequencies of gunfire? That would mean that upon firing a automatic weapon the person could also hear everything else such as their fellow team mates voices and more importantly enemy movement without obstruction?

[homedepotpro]

yeah my dads noise canceling headphones cancel out motor like frequencies but you can hear voices perfectly fine.

[paaiyan]

I can see several problems. First, actually getting the proper reversal of the sound wves. Second, chances are, your cannon won't produe the same exact noise every time. Everything can affect the noise made, fuel air ratio, humidity, temperature, exact weight of the projectile. You couldn't pull it off.

[keep_it_real]

It doesn't need to produce the same sound every time. During each shot, a microphone records the sound of the blast and instantly gives out the opposite sound of the noise.

It's really easy to get the proper reversal of sound waves. You just hook it up to a computer or noise canceling headphones.

[bboymatty]

Aircraft use noise cancelling equipment that works as you said (for the cancelling out of the turbine noise), but this is on a larger scale and is very expensive.

The best i think you can feasibly do buy some ear muffs and go for gold son, as Keep it real said the equipment for noise cancelling would probably be bigger than the gun itself

[boilingleadbath]

More problems than just being able to pull it off... I'm pretty sure that it's not possible; such a speaker setup is only able to cancel the sound in specific locations... and, indeed, it makes it louder in some places (constructive interference).
(ok, not true, but practically so)

So, I'm going to say... no, it's not possible to quiet the cannon from all directions at once using a speaker (probably an immensely powerful speaker at that) that's not at the same location as the muzzle.

[singularity]

im not saying i want ti to be completely silent i just want it to be muffled. im not saying it would be all the practical either but it would be fun to try (i got nothing better to do). let me revise my question, would an average surround sound system be able to at least dampen the sound of cannon fire?

[paaiyan]

Very doubtful. Most noise-cancelling equipment is meant to cancel the noise ina small area, headphnes for example. They aren't meant for a large scale cancellation, it would just take too much.