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Re: Making a parabola

Subject: Re: Making a parabola
From: "Klas Strandberg" klasstrandberg
Date: Sun Sep 23, 2012 8:36 am ((PDT))
I still think there are misunderstandings here:

Base cut during recording should be used only when there is risk for clippi=

but only then.

This is very important when using a parabola and there is side wind,
which it always is when aiming upwards. In such a case, even a quite
normal wind may cause turbulence in the dish and cause low freq.
peaks which are 40db or more above normal recording level.

Example: Using a Olympus LS-11 at "Low" sensitivity + the internal
base filter + setting the average recording level at -20 db, seems to
be good enough.

Another way is to cover the entire parabol opening with a cloth, like
fleece. Such a fleece will also dampen the sounds of insects hitting the di=

Other mic's:
At my soundcloud files with the SSM I have left the wind sounds
original, as I think they somewhat resemble what you would hear with
your ears, using Beyer DT990 headphones. Using other headphones, the
wind can be disturbing and then one has lo tower the base a bit.  But
even though the wind is audible, I do not hear it as a recording error.
Neither is the wind clipped. Therefore it can be adjusted in
post-production, if needed / wanted.

Put between a loudspeaker and a microphone, every material which has
a drastic effect on strong wind, will damped the signal at least 3 -
5 db at various frequencies, mostly above 7 Khz, depending on
material. This is quite a lot.
Foam with open cells is always a good start when making a wind shield.

If you need more than open cell foam, Lycra, which is used for
bathing suits, has so far been the best in test, which means "most
effect on wind vs. least effect on dampening high frequencies".

Some fleece materials are good, others are not. Knitted designs are
great, but not always, it depends on the yarn used and how tightly is
is knitted, e.t.c.

Making the "wind effect / dampening effect" measurements is easy.
What is a big problem is to buy the same material again. It seems
like a certain fake fur, for example, is made to meet a temporary
expected fashion on the market and three months later is it not there anymo=

Vicky, I think your problems with base cut and reshaping it is
because you don't know how the base filter is working.

If you make a white noise file and apply a base cut and save it, you
should get exactly the same sound back again, if you open it and
reverse the base cut.


At 02:29 2012-09-23, you wrote:

>On 22/09/2012, at 6:17 AM, Klas Strandberg wrote:
> >   I really don=B9t see how you could simply put  back bass that was
> > never recorded.>>
> >
> > Well, it "was" recorded, but at a lower level, not causing clipping.
> > Then it can (somewhat) be recovered.
>Just a couple of comments on the topic of applying low cut to your
>recording chain:
>In my experience of recording lyrebirds, I once made the mistake of
>having the low cut switch applied (in calm conditions, on LS10) when
>recording the peculiar 'dance' calls of a Superb Lyrebird.  These
>calls include a soft and rhythmic thudding sound.  I can say that,
>even with a good quality recording, I was UNABLE to properly recover
>those calls with post EQ.
>I have also noticed that with microphones that have a low cut switch,
>it can happen in some circumstances (again with lyrebirds) that loud
>repeated notes can sound slightly peculiar, slightly unpleasant, when
>recording with low cut switch applied.  The same calls sound
>perfectly fine with no low cut applied.  And this is even though the
>calls seem to be above the frequencies that the low cut is supposedly
>So my recording rule these days is, use absolutely no low cut
>whatsoever, IF YOU POSSIBLY CAN.  Make better windshields!
>Vicki Powys
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>Yahoo! Groups Links
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01

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