about the spherical windgag bit. i designed one and put it on shapeways so =
take a look for ideas. dont buy it, it is only for small cardioids like the=
neumans, and it really needs a bit more work. but i like the idea of two i=
dentical hemispheres, one holding each mike, you can rotate the two hemisph=
eres to get the angle you need and then cover it with a fleece cover.
=A0
umashankar
i have published my poems. you can read (or buy) at http://stores.lulu.com/=
umashankar
>________________________________
> From: Avocet <>
>To:
>Sent: Tuesday, January 24, 2012 5:09 AM
>Subject: Re: [Nature Recordists] wind protection options - any firm data?
>
>> My goal is to enhance my kit for recording in windier
>situation. I realise that a side effect of wind noise
>reduction is frequency attenuation. Yet manufacturers say
>little about this, likely because the effect is not
>significant for ENG work, compared with the dramatic
>improvements of reducing wind noise.
>
>Robin,
>
>Oh dear, just whe I was trying not to write like a geek, you
>come up with one of my favourite subjects.
>
>I can write a lot on windgags, but I won't here. My claim to
>fame is having done quite a lot of experimenting before
>Rycote happened, and invented a sock (The Brinisock) to go
>over their first garden mesh blimps. This was also an
>anti-rain sock which nobody has copied, but I was happy to
>stop selling mine to the BBC Film Unit after 100 or so and
>let Rycote make something similar.
>
>Parameters:
>
>1) Size. A small increase in windgag diameter gives a big increase in
>tolerable windspeed. There are equations for this but worth ignoring -
>just that the bigger of any radius of curvature the better, including
>edges and the mount.
>
>2) Cover: What any cover does is to provide a smooth
>interface to the wind to reduce turbulence. You don't need a
>cover fixed to the blimp cage provided it doesn't flap. The cover
>material should stop zero frequency (air movement) and attenuate the
>bass, acting as a high pass filter. You should be able to blow through
>it with a bit of resistance. Listen through it to see what it absorbs.
>
>3) HF Attenuation. Having taken care of the LF attenuation,
>you want minimum HF attenuation. The principle cause of this
>is the thickness of the layer or combined layers compared
>with the highest frequency wavelength. 16KHz is 21 mm and
>inversely pro rata. Perfection is thickness at 1/10 of the
>wavelength (including diagonal angles), but false fur still
>lets a lot of HF through and greatly reduces turbulence. The last
>thing you want is HF boosting if you have quiet locations not far
>above mic hiss.
>
>4) Frequency response. An effective gag material will cause
>reflections and a layer each side will create standing
>waves. You won't notice these as much on-axis but to the
>side they can be quite audible. You won't find any side
>angle response curves of directional mics as they are often
>very lumpy and get worse with a cylindrical windgag.
>
>I'm experimenting with a large spherical windgag over two
>gunmics but haven't worked out the mounting arrangement yet.
>I'm hoping it will cope with high winds.
>
>Almost forgot - try putting the windgag on the ground. It
>often sounds OK and there's a lot less wind down there. If it dosn't
>work at least you've tried it. :-)
>
>David
>
>David Brinicombe
>North Devon, UK
>Cogito cogito ergo cogito sum - Ambrose Bierce
>
>
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>
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