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Re: parabolic mics

Subject: Re: parabolic mics
From: "Avocet" madl74
Date: Tue Jun 14, 2011 9:35 am ((PDT))
> Question 2:
Is the parabola approach designed to be used with JUST omni mics?
Are other caption patterns allowed, or is it senseless to use
directional mics here?


As a supplementary answer, try any mic with a parabola and see what it
does. However, bear in mind that a double mic or a gunmic will be
wider or longer than the high frequency focus of the parabola so the
basic parabola theory won't apply.

> Does this enhance directivity for a shotgun?

You would be combining two very different directional principles and
it is unlikely that they would reinforce each other's characteristics
but try it. And it is likely that they would reinforce each other's

BTW I regard the MKH 416 one of the most useful mics available and
can't see how it can be improved on except for the MKH 816 (still
available second hand). If you have a bottomless pocket there is the
MKH 8070 which has an amazing spec but I can't afford two of them for
stereo. :-) I think the law of diminishing returns would act here,

Going to basic parabola theory:

a) The focus is finer at higher frequencies and virtually non-existant
at low freqencies.

b) An omni mic will pick up both direct sound and reflected sound and
at some frequenies these will tend to cancel out, but for most wanted
frequencies the reflected sound swamps the direct.

c) A cardioid theoretically avoids cancellation effect type b) but
other diffraction effects still apply. A cardioid is always more
susceptible to wind and handling noise. Take your pick on

d) Stereo with a parabola is only possible using two points just
off-focus on either side. The theory behind this is complex so trial
and error is the best method of finding out what works.


David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce

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