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Re: Re: the nature of parabolic reflectors

Subject: Re: Re: the nature of parabolic reflectors
From: "Randolph S. Little" <>
Date: Sun, 22 Feb 2004 09:35:54 -0500
Jeremy Minns (Greetings, Jeremy!) asked: "Does this explain why some member=
s of the list write that it is theoretically impossible to record very low =
frequency sounds with a parabolic reflector whereas others say that they ma=
nage to do it?"

To paraphrase Bill Clinton, this depends on which "this" this is.  The low-=
frequency response of parabolic microphone systems, i.e., frequencies whose=
 wavelengths are longer than the diameter of the reflector, is essentially =
the low-frequency of the microphone itself to such frequencies.

Once, when out recording with my 36-inch parabolic reflector and MKH-104 ca=
rdioid microphone, I encountered a Blue Grouse calling from high in a Red F=
ir.  By reversing the microphone so that it "pointed" out, I was able to ge=
t a recording, albeit without any acoustic gain contributed by the reflecto=
r.  The signal amplitude was comparable to what one would have obtained usi=
ng an MKH-816 (long shotgun), though the reduced directivity of the cardioi=
d also captured more of the off-axis background noise.

Good recording,
                              Randy


-----
Randolph S. Little <>
111 Berkeley Circle, Basking Ridge, NJ 07920-2009
Phone: (908)221-9173  Fax: (908)630-0871

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