David,
Once more thank you for your knowdlge and tips, they are precious.
About your previous ( in another post) coment and answer about the stereo s=
ound in a parabola, as you have said it is questionable but here are two fi=
les with mkh 30/40 in a 60cm fiberglass parabola 15cm focal lenght, once yo=
u have said, and it was right of corse, that the side gain was too low mayb=
e it was the case here I d'ont remember, now I balance the gain in the two =
channels better.
http://soundcloud.com/freitojos/120627t0600z-santmargdaserra
http://soundcloud.com/freitojos/122305t0600z-owls-cucoe
In my cans and in my speakers I think it is stereo.
My next experiment would be to put the mkh30/40 in my fiberglass 40 cm para=
bola and compare the results with those in the 60 cm parabola.
Regards,
Jos=E9
--- In "Avocet" <> wrote:
>
> > This formula is a general formula for waves, light, radio or sound
> > in a parabola,
>
> Jos=E9,
>
> This is exactly the problem. Sound waves are fundamentally different
> from light and radio waves. Firstly, they are longitudinal not lateral
> waves and secondly, their wavelength is comparable to the dimensions
> of the parabola. Thirdly we are using them over a 20:1 range of
> frequencies, not a narrow band like light or radio waves. The good
> news is that the coefficient of reflection of sound with a solid
> surface is near 100%.
>
> The bad news is that you won't get a clear focussed image from the
> dish. The best you can hope for is the sound equivalent of a fuzzy
> blob where most of the focussed energy will completely miss the mic.
> That's the simplest explanation for the loss of low frequencies where
> the blob gets larger. You can plot the focus pattern by moving around
> a small mic.
>
> A parabolic mic does its job well, which is bringing in kilohertz
> frequencies where it it more directional than any other type of mic.
> Just don't expect a good music balance from one. :-)
>
> A general rule with location sound recording is to use what works in
> practice. In the end our ears are the best judge rather than the
> theory.
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
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