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Author Topic: Is There A Sound Which Produces No Echo ?  (Read 12453 times)

Offline neilep

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Is There A Sound Which Produces No Echo ?
« on: 23/12/2006 03:56:49 »
Some of you may know of the Urban Myth that ' quack ' of a duck produces no echo. It is not true.

Wifey & I just saw a program that put a duck in a reverberation chamber and when it quacked...there was echo...of course !

But it got me thinking as to whether there it is possible to make a sound that produces negative echo...white noise ?

I don't know.

Do you ?


 

Offline Karen W.

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Re: Is There A Sound Which Produces No Echo ?
« Reply #1 on: 23/12/2006 04:01:58 »
NOPE! NOT ME!
 

Offline ukmicky

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Re: Is There A Sound Which Produces No Echo ?
« Reply #2 on: 23/12/2006 18:33:43 »
No never heard that one.
 

Offline iko

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Re: Is There A Sound Which Produces No Echo ?
« Reply #3 on: 23/12/2006 18:50:20 »
I think this is quite intriguing indeed,
but it should definitely go to Environmental issues &
Ecology!!!

Ecod  ;D ;D [:o)]
« Last Edit: 23/12/2006 18:52:27 by iko »
 

Offline Heliotrope

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Re: Is There A Sound Which Produces No Echo ?
« Reply #4 on: 25/12/2006 01:23:55 »
This entire issue is the wrong way around.
Echoing has absolutely nothing whatsoever to do with the sound itself.

The presence or not of an echo is decided by the properties of the material that the sound wave interacts with.

General principles are : flat and smooth gives good reflections ie. echoes.
Rough and broken gives much less of an echo.

If you stuff a duck into an anechoic chamber and prod it with a stick so it quacks in protest there will be no echo.
If you stuff a duck in a concrete room with smoothly painted walls there will be an echo when it quacks.
If you stuff a duck and then put it in the oven you'd better get the orange sauce on because duck gets done quite quickly.
;D
« Last Edit: 25/12/2006 15:30:53 by Heliotrope »
 

Offline Heliotrope

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Re: Is There A Sound Which Produces No Echo ?
« Reply #5 on: 25/12/2006 01:28:12 »
It is possible to arrange things with multiple speakers emitting a pure tone so that when you stand in a particular place you can't her anything coming out of them no matter how loud you turn the volume up.
This is all about the addition and subtraction of waves.
It's a bit harder to work out where you should stand but it is possible to do this with reflected sound too.
The sound still reflects but when it eventually comes together at your ear all the positive going waves are cancelled by the negative going waves and you hear no sound.

This is an extremely contrived setup however and you would have difficulty reproducing the effect with your 7:1 home theatre system.
 

Offline DoctorBeaver

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Re: Is There A Sound Which Produces No Echo ?
« Reply #6 on: 02/01/2007 20:00:00 »
Put the duck in a vacuum chamber and you won't hear it quack. You won't hear it explode due to pressure differential either!  :D
 

Offline neilep

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Re: Is There A Sound Which Produces No Echo ?
« Reply #7 on: 02/01/2007 23:29:34 »
Put the duck in a vacuum chamber and you won't hear it quack. You won't hear it explode due to pressure differential either!  :D

Isn't that an Indian dish called BOMB-bay Duck ?.....which we all know is really a fish !!
 

Offline ukmicky

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Re: Is There A Sound Which Produces No Echo ?
« Reply #8 on: 03/01/2007 02:48:20 »
I would say yes it would be possible but you would have to restrict the sound to frequencys beyond the the range at which we can hear,  As you know neil its possible to produce sub frequencies which can pass through walls etc, take them even lower and i suppose they could pass through most things without bouncing back.
« Last Edit: 03/01/2007 02:51:52 by ukmicky »
 

Offline neilep

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Re: Is There A Sound Which Produces No Echo ?
« Reply #9 on: 03/01/2007 02:51:35 »
i would say yes it would be possible but you would have to restrict the sound to frequencys beyond the the range at which we can hear,  cotrol the fequenc

HI MICHAEL !! (Hugs the Michael, misses the Michael)

Are you sure....? just because it's out of our hearing range does not mean it won't echo !!..or will it !!?..I don't know..I'm just a sheep !!..
 

Offline ukmicky

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Re: Is There A Sound Which Produces No Echo ?
« Reply #10 on: 03/01/2007 02:57:01 »
Damn your quick,you didnt even give me a chance to remove my error.:)

To produce an echo sound has to bounce back and forwards,sub frequencies can go through things and carry over long distances due to the fact that they pass straight through objects without bouncing back off them 

I WOULD HAVE THOUGHT.:)
 

Offline neilep

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Re: Is There A Sound Which Produces No Echo ?
« Reply #11 on: 03/01/2007 03:02:33 »
Mate..just delete the posts ok..leaving your amended post
 

Offline ukmicky

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Re: Is There A Sound Which Produces No Echo ?
« Reply #12 on: 03/01/2007 03:17:51 »
Na it vill yeach me two get tings wrght first time.
 

Offline neilep

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Re: Is There A Sound Which Produces No Echo ?
« Reply #13 on: 03/01/2007 04:09:25 »
Na it vill yeach me two get tings wrght first time.

Including your spelling !! ;)
 

Offline Karen W.

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Re: Is There A Sound Which Produces No Echo ?
« Reply #14 on: 03/01/2007 04:15:57 »
LOL LOL!!
 

ROBERT

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Is There A Sound Which Produces No Echo ?
« Reply #15 on: 10/01/2007 14:57:36 »
It is possible to arrange things with multiple speakers emitting a pure tone so that when you stand in a particular place you can't her anything coming out of them no matter how loud you turn the volume up.
This is all about the addition and subtraction of waves.
It's a bit harder to work out where you should stand but it is possible to do this with reflected sound too.
The sound still reflects but when it eventually comes together at your ear all the positive going waves are cancelled by the negative going waves and you hear no sound.

This is an extremely contrived setup however and you would have difficulty reproducing the effect with your 7:1 home theatre system.

Noise cancelling headphones use the destructive interference effect you have described.
http://en.wikipedia.org/wiki/Noise-cancelling_headphone
« Last Edit: 10/01/2007 14:59:25 by ROBERT »
 

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Is There A Sound Which Produces No Echo ?
« Reply #15 on: 10/01/2007 14:57:36 »

 

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