Syd Curtis wrote:
> ... "Half the distance and double the signal."
>
> Getting close is in fact even more effective than that. Signal strength is
> inversely proportional to the square of the distance. So that half the
> distance means four times the signal strength.
Inverse square holds for free field (open 3-D acoustic space in all directions)
but I wonder if there shouldn't be a correction for half-space, where the
ground reflects half (or no more than half) of the acoustic energy back
into the non-planet part of our atmosphere. The inverse-square law breaks
down inside inclosed (reverbrant) spaces where the (non-)decay of reflect
energy can dominate the soundfield. And inside an acoustic waveguide (pipe)
there may be very little attenuation with distance.
This is just a techincal nit, and inverse-square is 1st approximation for
outdoors acoustics. But in some of the recently posted recordings
I've heard some pretty interesting reflections. Gotta dig out the acoustics
text to check the intensity law in 1/2-space, where most of us record.
-- Mike
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