Kevin Colver wrote:
> Further testing this afternoon confirms the central "hole." The right
> focus is definitely to the right a bit and left off to the left. This
> is on the setup with 2 mono mics spaced a bit to the side of middle but
> in the plane of focus. I imagine the Telinga stereo doesn't have this
> problem does it?
> Kevin J. Colver
As far as I've been able to tell, no hole with the Telinga. And that's
in a few years of use. This is the Telinga stereo recording subjects
that are mostly a fair ways away:
http://loscan.home.mindspring.com/SavannahNWR.mp3
And these two are closer subjects:
http://loscan.home.mindspring.com/S.Telinga.DATStereo.mp3
http://loscan.home.mindspring.com/B.Telinga.DATStereo.mp3
You had a pretty wide spacing for a 24" dish, try it with less space.
You may have to organize a more solid support to be sure.
Note that you can expect that the max intensity will be a bit right or
left for each channel, part of what gives you a stereo image. The hole
is if the sum of the two has a noticeable intensity dip at center.
Ideally, a insect flying across your field should build to center
evenly, then die off evenly the other side of center.
The system you used is XY stereo, and one of the problems is that
neither mic is pointed straight center, running at optimum, I expect
this is so even for the parabolic setup as a unit. That's one of the
advantages of the M/S setups, your mid mic is right on axis along it's
optimum pickup. The max angle for XY is limited by either off axis
coloration or falloff in center. Works well up to that point. And you
usually have to experiment to find that point.
I've a couple other ideas how to do this, but it's going to depend on
machining the parts and seeing if anything happens right.
Walt
________________________________________________________________________
________________________________________________________________________
|