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Re: Noise Filetering Software Advice

Subject: Re: Noise Filetering Software Advice
From: "Walter Knapp" waltknapp
Date: Sun Dec 24, 2006 7:47 am ((PST))
Posted by: "Bob McLean"

> Can anyone suggest software (MAC OS X) for safe wind noise removal / redu=
ction?

I'm a mac user, but the software I use is no longer sold (TC Works -
Spark XL). The important feature with it is that you can stack filters
and audition them in realtime. I normally have at the end of the stack a
sonogram display so I can know exactly what the filters are doing.

I also use Elemental Audio's Equium plug in filter a lot. This can be
plugged into a lot of different sound editing software. The problem here
is they have sold out their filters to another company, which looks like
it's going to raise the price.

> I'm a birdwatcher using recording to assist identification.  I've begun u=
sing sonagram
> analysis to further assist identification, but wind noise gets in the way=
 of this analysis.  I have
> tried Sound Studio and Audacity but have not found the secret to filterin=
g without destroying
> =96 distorting the sound.

The secret to filtering is to use a light hand. Sometimes several light
passes will work where one heavy one won't.

Filtering is no magic bullet, it's limited in what it can do. The big
secret to quality recordings is to get recordings that don't need
filtering. Not always easy.

> Of course the obvious solution would be to eliminate the wind noise.  I a=
m using a field
> recording vest with binaural mics on the shoulders enclosed in 1.5" diame=
ter cages covered
> with fake fur.  Noise protection is good from wind to about 10mph and is =
quite impossible
> with the 20+mph winds I frequently encounter.  Such is the life of a bird=
watcher.
>
> Any tricks, suggestions, clues would be appreciated.

Complete removal of wind noise after the fact is tough. Usually the best
you can do is a combination of several filters lightly applied. It is a
lot easier if the calls you want are of a limited frequency range.

Of the mics I have the Telinga is capable of making a usable recording
in higher wind than the others. The dish provides a windbreak. It's the
mainstay of my frog survey recordings.

For other mics the trick is layers. What actually stops the wind from
reaching the mics is the layers of dead airspace.  You might try a cover
directly on the mics inside the fake fur to add another layer of
protection. This won't stop the sound of the wind in the environment,
which you just have to live with.

Location can help, try finding a recording location where the mic is
more sheltered from the wind. If nothing else, try right down on the
ground under your subject.

Walt




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