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Re: parabolic mics + recorder noise

Subject: Re: parabolic mics + recorder noise
From: "Avocet" madl74
Date: Sat Jun 4, 2011 11:29 am ((PDT))
> And it has not a "wonky" frequency response, but a frequency
> response
> of a parabol, which is a very good freq. response for certain
> purposes.


In the context of advising a newcomer to field recording, I would not
recommend a parabola as a first mic. Parabolas have their place and
can do things a gunmic can't do but what they don't have is a flat
frequency response which is what a beginner should start with, even is
they modify the response after recording, particularly at the bass

I'm writing an article on the acoustics of reflector microphones and
I'll show it you you when it is readable. A key point is that you are
recording a diffraction pattern, not an optical type focus.

> Which means: IF you connect a modern microphone to a modern
> recorder,
> this microphone will provide such a powerful output signal, that it
> is the microphone noise that will be disturbing.

Yes, agreed, and that is why I use MKH series mics. The 416 had a spec
of 21dB excess noise over thermal noise weighted CCIR 468-3. This is
the noise you can hear but you can't compare this in any way with
different noise quotes and different weightings, especially ones
measured with the capsule disconnected. In fact the only noise figure
which counts is the one measured by your ears in your typical
environment. The 21dB '468 weighted' mic I quoted is one of the
quietist that you will find.

To come to the defence of parabolic microphones, the gain they give at
the higher frequencies means the that the effective excess noise over
thermal noise mic hiss figure as recorded is very low.


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

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