folks,
when discussing parabolas, please remember that we have to deal with
long wave-length material, sound, and not light.
However, by pointing with the Telinga dish at the sun, it is possible
to set fire to a piece of paper in a few seconds. And I have replaced
the foam of a few mic's, after being accidentally burned.
When doing all the compromises one has do to with a parabol, the
"ideal" focus is different if you have an omni, a cardioid or a
Telinga stereo mic.
As the best sound you can get is not always when aiming exactly at
the bird, or being as close to the bird as possible, the best sound
is not always achieved when the mic is exactly in focus.
And the "ideal" focal length varies with the distance to the source.
All of this has to be experienced by trial and error.
Klas
At 14:14 2012-01-20, you wrote:
>I can add that in Telinga Universal, the hole for the mic in the
>foam is fitting a AT4022 that is 22mm in diameter (or similar mic),
>som no need for adjustments.
>
>
>--- In "Ian Martin" <> wro=
te:
> >
> > Hi Chris
> >
> > Re Telinga 1mm (roll up) dish
> >
> > Dish Dia incl rim approx 590 mm
> > Dish Dia w/o rim approx 530 - 540 mm
> > Dish depth incl rim approx 145 mm
> > Dish depth w/o rim approx 135 mm
> > Hole dia approx 38.5 mm
> >
> > If I had some sunlight I could do a rough focus test for you but it is
> > dead overcast here in Newcastle NSW today.
> >
> > Caveat: The dish was in a less than ideal position for measuring, some
> > measurements such as dia w/o rim and depth w/o rim are difficult due to
> > the absence of a precise boundary between the rim and the dished part
> > :-( That said, the hole dia is pretty accurate for the dish that I have=
.
> >
> > The internal dimensions of the box it came in are approximately 155mm
> > deep by 610mm square
> >
> > It will of course roll up into a cigar shape and fit into a cylindrical
> > bag.
> >
> > Cheers
> > Ian
> >
> > -----
> > Ian Martin Newcastle, NSW, Australia
> >
> >
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