If we begin with a loud sound and add a copy of that soundwave that is 1/2 cycle or wavelength out of phase with the first soundwave, will destructive interference mute or dilute the amplitude of both sounds? :)

Originally posted by Natural
If we begin with a loud sound and add a copy of that soundwave that is 1/2 cycle or wavelength out of phase with the first soundwave, will destructive interference mute or dilute the amplitude of both sounds? :)

You answered your own question...hence destructive interference

Then why isn't this approach used to muffle sounds, or is it? I work in an industry where noise can sometimes be a problem and must be muffled (at great expense) but I've never heard of such technology.

Car Mufflers work by doing that already!

http://auto.howstuffworks.com/muffler.htm

Thanks fetus, that's interesting. Ever heard of any examples of this principle not in an enclosure?

Dolby Noise Reduction uses an inverted sound wave to reduce the static noise of recordings. and it does it electronically, in real time!! cool stuff, that.

Is there a way, transfering the wave to different materials, not using an active system, to perhaps delay part of the wave, producing an inverse?

Natural,

Yes I have, I hear of focused sound speaks, by placing several in a line and electronically controlling each ones output and phase with each other, most of the sound can be cancel out except for a focused, electrically aimed beam . It planed for use as a sonic less-then-lethal weapon and making interactive advertisements.

It planed for use as a sonic less-then-lethal weapon and making interactive advertisements.

I should have guessed the powers that be would try to use it for a weapon. :bugeye:
Maybe its also involved in the production of surround sound or "holographic" sound systems.
Anyway, it's news to me. Thanks WellCookedFetus.

Such phase cancellation is used a lot in recording studios to prevent spillage between mics etc.

Someone should really make electronic headphones which take, as input, the sound before you would hear it, and then produce the opposite waveforms----that way you get complete silence:)

Such a product would sell very well, I would imagine-----especially for people in high noise industries.

Try a search on "active earmuffs".

Very cool, Pete. Just what I was looking for! Thanx. :)