Arie Verveer wrote:
> David,
> 
> A few year ago I ran an infra-sound detector and found
> the air currents caused a great deal of problems.
> Basically most of the signal. Only having a limited
> space, I opted for a long length of thin wall silicon tube
> coiled in a spiral. This tube was purchased from a medical
> supplier. It acted a a large diaphragm reducing the air
> currents at the detectors input. I managed to detect
> the air pressure induced by the movement of a small local
> quake (100 km away) that shook the ground under the detector.
> A few observed meteors were detected plus some interesting
> yearly changes in the background noise (ocean). I do think the
> radial arm on porous tubes close to the ground would be
> the best way forward assuming you have the space. My
> detector operated 10 hz and lower.
(snip)

Do you have any idea what your pressure transducer's sensitivity to 
acceleration is?  Unless it is a balanced design that specifically 
cancels the effects of acceleration, you may have seen a signal that 
was a combination of pressure and sensor movement.
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