At 03:38 PM 9/17/99 -0700, Eric Reikes wrote:
>>True, I'd expect the sound to travel out in a sphere.  However,
>>the curve you get where the DIFFERENCE in distance to two points is a
>>constant is a hyperbola.  Let's see if I can remember it...  I think it's
>>
>>        1 = x^2/a^2 - y^2/b^2
>>
>>        You get various conic sections by messing with this.  The minus
>>makes it a hyperbola.  Change it to a plus and you get an ellipse where a
>>and b are half the length of the axis.  Make them equal and they are the
>>radius of the circle.
>>
>
>Seems to me that givena reasonably sensitive receive circuit all you would
>have to do would be to have a directional detector, and slew it around on
>some kind of gimbal....

For some reason, I didn't get Harold's response to my post.

The hyperbola is apparently the locus in the plane of all aliased points
that would have given the same time delay at the dipole of microphone
receivers.

Obviously 2 mikes will not provide an accurate position in the plane, or
even an angle. You need 3 mikes to do this. (This gives two independent
timing intervals, which gives a single point locus.) With two intervals,
the ability to time both (which may be simultaneous) accuracy is a
performance issue.

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Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral@lcfltd.com
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