Thanks David & umashankar for your tips. I look forward to experimenting wi=
th some different arrays & comparing the results.
--- In umashankar <> wrote:
>
> 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.co=
m/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.=A0thi=
s includes the crown sass/=A0there was a very good article on the crown web=
site 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=
this transition frequency, the omni mic mounted on the boundary gets a mor=
e and more omnidirection directivity pattern=A0 ( i think roughly 6 db/octa=
ve)
> >=A0
> >the net result is the noise gain of the microphone is independent of fre=
quency, though the directivity pattern and front gain, rises till it reache=
s cut off frequency and then stays flat.
> >=A0
> >one array i had built myself consisted of two six inch square acrylic pl=
ates hinged together. each plate contained five six mm omni capsules glued =
flush to the surface in an irregular cross, the capsules were paralleled. t=
his gave me a microphone with surprising directivity and gain, and the two =
hinged plates gave me a stereo pair with adjustable angle between the micro=
phones
> >=A0
> >i got some nice results with both nature recordings and music with this =
array about 20 years ago.
> >=A0
> >umashankar
> >=A0
> >=A0
> >
> >i have published my poems. you can read (or buy) at http://stores.lulu.c=
om/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
> >>
|