okay..now how do we shut down the soundthis query has made on the list
alok


> -----Original Message-----
> From: M. Adam Davis [SMTP:adavis@UBASICS.COM]
> Sent: Wednesday, April 12, 2000 6:48 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [OT] INVERTE THE WAVE
>
> Just had another thought.  One thing you can do to null out the sound is
> to
> track everyone on the factory floor within earshot of the machine.  Once
> you
> know their location to within a few inches (particularily the location of
> each
> head, or even each ear) then you can solve a series of simultaneous
> equations
> which will determine the phase of sound you should produce from a speaker
> near
> the machine.  This equation will give the best noise dampening for each
> person,
> given that a few aren't in optimal positions.
>
> It occured to me as I was thinking about the program I am currently
> working on.
> A long rotating shaft will have different unbalances along its length.
> Balancing one point on the shaft affects the balance of all other points
> on the
> shaft, so you need to find out how much each point affects the others, and
> then
> solve a whole slew of simultaneous equatons to find the 'best' balance for
> every
> point on the shaft.
>
> Some people in the factory will be in optimal positions, but others will
> not.
> You can find the best phase to output which will place each person as
> close as
> possible to a nulled area of sound.
>
> Of course, this will help a teeny bit, but sound bouncing around the
> factory
> will also have to be nulled seperately.  In a completely deadened room
> this
> would work beautifully.
>
> Make it a bit more complex:  Space speakers above the factory floor every
> 20
> feet or 4 meters.  then solve a series of simultaneous equations which
> deadens
> sound even better.  You could almost create a sound curtain, such that
> particular area in the factory is completely quiet, almost like being in
> an
> office, but it is open air.  This solution would require several
> magnitudes
> greater computer power than the suggestion above, but you may not need to
> deaden
> the sound reflections as much, this system could handle them as well.  Not
> for
> the faint of heart, the equations alone are mind bending, not to mention
> trying
> to fit them in a computer, nevermind a DSP...
>
> -Adam
>
> > WF wrote:
> >
> >     Hi,
> >
> >     A student is studyng how to invert some wave...
> >
> >     He intends to NULL some produced sound...in the factory that he
> works have
> > some TEXTIL machines and intends to reduce the noise produced by
> > them...applyng a inverted wave...
> >
> >     Does someone have some suggestions about this? Formula, site, etc...
> >
> >     I think that is too hard!
> >
> >     Miguel Wisintainer
> >