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Re: Lightweight array suggestions

Subject: Re: Lightweight array suggestions
From: "umashankar" umashanks
Date: Tue Aug 30, 2011 6:16 am ((PDT))
the article i was talking about has a link in the wiki on pzm


i have published my poems. you can read (or buy) at http://stores.lulu.com/=
umashankar

From: umashankar <>
>To: "" <>
>Sent: Tuesday, August 30, 2011 6:34 PM
>Subject: Re: [Nature Recordists] Lightweight array suggestions
>
>boundary layer microphones have a slightly different set of rules.=A0this =
includes the crown sass/=A0there was a very good article on the crown websi=
te many years ago, but briefly stated, the longest wavelength suppported by=
 a boundary plate is six times the longest dimension of the plate. and at t=
his transition frequency, the omni mic mounted on the boundary gets a more =
and more omnidirection directivity pattern=A0 ( i think roughly 6 db/octave=
)
>=A0
>the net result is the noise gain of the microphone is independent of frequ=
ency, though the directivity pattern and front gain, rises till it reaches =
cut off frequency and then stays flat.
>=A0
>one array i had built myself consisted of two six inch square acrylic plat=
es hinged together. each plate contained five six mm omni capsules glued fl=
ush to the surface in an irregular cross, the capsules were paralleled. thi=
s gave me a microphone with surprising directivity and gain, and the two hi=
nged plates gave me a stereo pair with adjustable angle between the microph=
ones
>=A0
>i got some nice results with both nature recordings and music with this ar=
ray about 20 years ago.
>=A0
>umashankar
>=A0
>=A0
>
>i have published my poems. you can read (or buy) at http://stores.lulu.com=
/umashankar
>
>From: Avocet <>
>>To: 
>>Sent: Tuesday, August 30, 2011 6:20 PM
>>Subject: Re: [Nature Recordists] Lightweight array suggestions
>>
>>> I would like to make an array that is as light & transportable as
>>> possible, yet won't be easily damaged.
>>
>>Marc,
>>
>>There is a golden rule with most arrays if you are interested in
>>medium to low frequencies as heard in forests, and that is the size of
>>any baffle or boundary should be comparable to the wavelength. At
>>500Hz the wavelength is 680mm. (27")
>>
>>An exception to this rule is with an M-S mic or a double cardioid pair
>>which will give you a good stereo image with a wide frequency response
>>and - importantly - is easy to carry and deploy and shield from wind,
>>rain and insects with standard windgags.
>>
>>David
>>
>>David Brinicombe
>>North Devon, UK
>>Cogito cogito ergo cogito sum - Ambrose Bierce
>>



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