Hi Dana,
there's a few things to point out here that might be generally
applicable when a new recordist asks "How can I clean this up?".
The first is a bit philosophical: How natural is your recording when you
decide that some of the natural sounds (i.e the birds) belong there, and
some of the natural sounds (i.e. the insects) don't? I went through a
lot of agony in Brazil once trying to separate the "pure natural" sounds
I wanted from the ones I didn't want before I realized that the problem
wasn't with the sounds I was trying (not) to record...it was with me and
my wanting to extract things from their natural environment! Especially
when one comes from a background of photography, where things can just
be cropped out of the picture, the idea of sound being "messy" is hard
to get used to. It's all around, and you can't get rid of it just by
"cropping" the soundfile or pointing the mic in another direction.
Sometimes it's better to think of the sound more in a more holistic way
rather than becoming too fixated on only one small part.
In terms of post-production techniques, I avoid most FFT-based noise
reduction filters as much as possible. They have powerful abilities to
extract and remove certain frequencies, but at the cost of the totality
of the sound. Most people quickly notice that you get very
artificial-sounding sinusoid tones when these FFT filters get over-used.
And since one frequency may exist as a major component of two
sounds--one "desirable" and one "undesirable"--simply removing it
altogether will harm your overall mix more than help.
Rather than a highly aggressive noise reduction plugin, I would
recommend using a multiband equalizer, possibly even with a set of
frequency-band compressors (lo, mid, hi at least). With a multiband EQ,
the frequency "slices" you emphasize or remove are a bit broader, and
less destructive to the overall sound. And with a set of compressors,
you can highlight the "desirable" features of the sound better by giving
them a little "lift" out of the background. On top of that, if you
manipulate the EQ in realtime as your sound is playing, rather than just
running your whole sound through one plugin preset, you can make subtle
changes to the soundfield which help draw attention to your subject much
better.
Others might disagree with me on this point, and on the use of
compressors in particular, but it is purely a personal preference. My
own post-production tool of choice is a multiband EQ with dynamics
processing from the Free + Open Source Software world called Jamin. It
was made for Linux and a set of audio drivers called JACK, and with some
work you can get it running on OSX:
http://jamin.sourceforge.net/en/about.html
http://jackaudio.org/
http://www.jackosx.com/
That aside, most DAW software should have a decent multiband EQ and
compressor/limiter/expander capabilities, so practice a bit trying to
use them without using them noticeably.
Last of all, I might point out that a good field recording starts in the
field. Relying on the ability to "fix it in post" is usually the last
resort when some sort of mistake has been made, in my opinion. Ask any
of the professional recordists on the RAMPS list, and you'll get the
same reply--only a very bad production "fixes it in post" rather than
getting it right during the takes. I personally see most of my
post-production techniques more as a mastering process than a cleanup.
You have some top quality gear there with the MKH mics and the
Portadisc, and therefore have the ability to make GOOD recordings in the
field without having to scrub them too much later. I would spend more
time experimenting with different mic techniques and positions. There's
been some very good threads in this group on this topic the last few
weeks, so dive right in!
Good luck,
d.
Dana Blackmer wrote:
> The link at the end of this message is to a 68 second mp3 file of a
> dawn chorus I recorded last Sunday in Jefferson National Forest in
> southwest Virginia. I am new at nature recording, and wanted some
> suggestions as to how to reduce the low end rumble, hiss, and if
> possible, some of the insect noises.
>
> The attached clip has most of the challenges I'd like to address:
>
> 1 - Thoughout the recording there is low frequency buzzing from
> insects. Can this sound be filtered out or diminished without
> getting the "blurby" sounds I sometimes get with a filter? Can this
> noise be reduced without decreasing the quality of the other low
> frequency sounds?
>
> 2 - There is some high frequency hiss in the recording. How would
> you reduce this without substantially changing some of the high
> frequency sounds, like the bird call from 1:05 to 1:08?
>
> 3 - At 1.5 seconds and again around 18 seconds an insect flies by -
> is there a way to decrease or eliminate this without substantially
> changing other low frequency sounds, like the "gunk, gunk" calls of
> the green frogs in the background?
>
> Generally, I am looking for some guidelines as to how to approach
> the task of post-production - what filters, noise-reduction methods,
> EQ, etc. to use, in what order, and how to do this without making
> the result sound too sterile. Any advise would be greatly
> appreciated.
>
> FYI, I used an HBB Portadisc and MKH 30/40 to get the recording and
> will be using Adobe Audtion 1.5 to do any post stuff. The only
> thing I did to the attached file was to mix the MS to XY using
> Audition's channel mixer at the default settings and saved the file
> as an mp3 to save some space.
>
> Thanks in advance to anyone who can give me some suggestions. My
> hope is that the more experienced of you can educating the less
> experienced of us in the science and art of what to do after you've
> finished recording.
>
> Dana
>
> http://www.danablackmer.com/AudioFiles/DawnChorus.mp3
--
derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 19:
"Be dirty"
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