[PD] Re: multi-speaker panning.. problamtic maths
czhenry at gmail.com
Fri Oct 27 01:43:43 CEST 2006
> I made this mistake again last thursday - I computed sound amplitude of
> some kind of omnidirectional source as being r^-2 where r is the distance.
> However, I believe that it's energy that should be r^-2, therefore
> amplitude should be r^-1. That's assuming ideal 3-D dispersion (no
> ceilings and no walls). Is that right?
Exactly right. For that ideal environment, we have the intensity
(W/m^2) distributed evenly on the surface of a sphere at radius r.
So, since the surface area of the sphere varies as r^2, the intensity
falls off at a rate of r^-2. The energy of the wave is (mostly)
conserved, it just gets spread out over a larger area.
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