--- In Rob Danielson <> wrote:
>
> At 11:44 PM +0000 3/8/06, nbioacoustics wrote:
> >Hi there,
> >
> >Does anyone know of a piece of software that is able to filter out
> >wind or background noise from bioacoustic recordings?
> >
> >Thanks,
> >Natalie :)
> >
>
> Hi Natalie--
>
> "Wind or Background Noise" could include many phenomena, type of
> sounds. Looking at a waveform of your recording, you might notice
> some pronounced, horizontally wide, wave shapes. These may stem from
> the wind moving the mic diaphragm physically. The ill affects of such
> distortion cannot be removed, but sometimes they can be made less
> noticeable by very low frequency filtering. Most waveform editing
> software programs have "high pass" or "Low cut" filters that can
> address just the lowest frequencies. There's usually no reason to
> filter (cut) above 30Hz, but the pulses are often very high in
> amplitude and your speakers may still create audible harmonic
> artifacts of their presence. In this case, try applying several
> filters--all below 30Hz. Another way is to measure the Hz, e.g. 6Hz
> and apply very sharp parametric EQ. Wind can produce other problems
> this will not address, of course. Rob D.
>
>
>
> --
> Rob Danielson
> Film Department
> University of Wisconsin-Milwaukee
>
I looked for your file, but it seems to have been removed. So this my
comments apply in general and not to your specific situation.
I'm much less conservative than Rob is. I would use a High-pass filter
and bring the cutoff frequency up until I started to lose the sound that
I was intending to record, and then back off of it a bit.
You could also try a noise reduction program, like the one in Audacity
(a free program) http://audacity.sourceforge.net/about/features .
These types of filters work best on non-dynamic typs of noise- which
does not include wind, and when overused they make the audio sound very
swirly. They can be useful under certain situations.
As a general comment-- not directed to you specifically, Natilie, I
would say that a good shockmount and wind screen is probably one of the
most critical pieces of recording equipment, if not the most important.
Nearly every day someone posts to one of the groups that I susbscribe
asking what the best mic setup for under X$ is. I have heard amazing
recordings that used less than perfect microphones, and I've heard
millions upon millions of recordings that used fantastic mics, but were
not properly shielded from wind and vibrations, which rendered the
recordings nearly useless.
-Richard Humphries
Sound Designer, Re-recording Mixer
[Non-text portions of this message have been removed]
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