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Re: Nature recording 101

Subject: Re: Nature recording 101
From: Klas Strandberg <>
Date: Wed, 23 Feb 2005 23:23:58 +0100
Sorry, I'm sending the wrong postings to the wrong people here.

An omni is a closed cylindrical can with a membrane as one of it's sides.
The pressure inside of it tends to be constant, and tend to keep the
membrane still, not so much affected by wind. (Or movement - handling
noise). The membrane moves because the pressure inside the can is compared=

to the pressure outside of it.

A directional mic is a tube, with a membrane as the only one side. Both
sides of the membrane will get affected by wind, and there is no "constant=

pressure" tending to hold the membrane still.
Therefore a directional mic need a much better wind protection than an omni=

and is also more sensitive to handling noise.

Imagine a tin-can where you have removed one side and replaced it with a
piece of balloon-rubber. Imagine you blow on the rubber. It will not go so=

much inwards, as the pressure inside the can will hold it where it is.
Imagine you move it. The same thing will happen. The membrane will not move=

much.

Now imagine that you take a tube and place the same rubber over it and try=

the same experiments.

If both have excellent suspension and wind protection, you will not find
much difference.

Klas.


At 17:51 2005-02-23, you wrote:

>Thanks, Klas, and let me get Rob off the hook - it wasn't him who posted
>this but me, a newbie who really only has experience with indoor
>recording.  So I'm hearing this about omnis and wind reduction for the
>first time.  I'm not entirely clear on the theory behind this...
>
>As far as zeroing my meters, (0db, but not clipping) I did have the pres
>up pretty far as the sounds were distant and only reaching -6DB
>max.  Sections where the wind was calm reveal a recording free of
>distortion so far as I can tell so far.
>
>Anyway thanks again, I have some reading to do about basics, obviously.
>
>Ken
>
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>[Non-text portions of this message have been removed]
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>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>

Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email: 
        

[Non-text portions of this message have been removed]



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