From: John Woodgate
Subject: Re: Shotgun Microphone Capsule Design
Date: Sat, 7 Dec 2002 23:02:51 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Sun, 8 Dec 2002 05:10:29 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that James Barabas
wrote (in ) about 'Shotgun Microphone Capsule Design', on Sat, 7 Dec 2002:
>Right, so the tube will be closed at the back end and open at the front,
>with the microphone near the back.
AT the back, not near it. Close the other end as well.
> Since I'll be using a directional
>element, I want to align its axis with the tube (pointing forward), but
>does exact front-back placement matter? The element in a Sennheiser I was
>looking at seemed to be a bit forward of the last vent...
What Sennheiser do may just confuse you. Keep it simple, with the
microphone at the back. The cardioid capsule has two sound entry points.
The front one attaches to the tube, while the back one remains
>> >Most of the commercial shotguns I've seen use many small vents instead of
>> >a single long slit. Is there any advantage to this design?
>> No; It's mechanically stronger.
>Does the ratio of intact actual tube to vent area matter?
Yes: at least 50% vent area.
>I'm also wondering about the screens used on commercial shotguns. Do I
>need to cover the front-end/vents for acoustic reasons or do the screens
>just keep junk out of the tube?
Seal the front end. If you use vents, you need a thin open-weave fabric
grille (a bit of 5 denier nylon might do) to keep bugs out of the tube.
If one gets in, it's LOUD!!!
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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