Subject: Re: Sound cancellation technology?
Organization: The Armory
X-Newsreader: trn 4.0-test69 (20 September 1998)
From: firstname.lastname@example.org (Richard Steven Walz)
Date: 27 Dec 2002 04:01:17 GMT
In article ,
Phil Allison wrote:
>"John Woodgate" wrote in message
>> I read in sci.electronics.design that Lady Liberty
>> wrote (in > .124.0.13>) about 'Sound cancellation technology?', on Wed, 25 Dec 2002:
>> >Fine but not my question. Could someone please answer the actual
>> OK, it is almost certainly possible, but would be very costly, not
>> necessarily in terms of equipment but in the custom DSP software
> ** Really ?
> How do you cancell by a factor of 60 dB *any* noise that intrudes
>into a bedroom ? This may include barking dogs next to the window, road
>traffic noise of all sorts at close range, aircraft noise, neighbours
>activity impacting the floor/ceiling interface with deep, powerfull sub
>sonics etc, etc.
> These create sudden and disturbing noise in the room at almost any
>frequency 60 dB or more above ambient with attendant internal reverberation
>and varying phase at any point and arriving from any of dozens of sources
>and directions ??
> .................... Phil
If you mapped transducers onto the entire areal perimeter of the room on
its walls where sound enters, it is theoretically possible by Kirchhoff
diffraction analysis to counter any sound energy entering the room using
Kirchhoffian wavelet inversion. But, of course, that's a real PITA.
-Steve Walz email@example.com ftp://ftp.armory.com/pub/user/rstevew
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