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Re: An exercise in noise reduction

Subject: Re: An exercise in noise reduction
From: "Rich Peet" <>
Date: Tue, 28 Oct 2003 22:25:06 -0000
I played for a bit and had great fun with these sounds in Audition 
1.0.  I found in order to eliminate the water sound I had to hit the 
noise reduction as hard as I have ever tried to hit anything.  I can 
not say it is better than the original because the water sound does 
add something.  If the goal is reduction of the water sound all I 
would get with a lighter noise reduction setting was artifact.  So I 
went with the option of hitting it so hard as to try and kill it 
completely.  These mp3's are very small for download.

Bloop
Applied hard noise reduction at 100% with a reduction of 75 db having 
taken a sample to model the reduction from a quiet segment at the 
end.  This probably did reduce the echo effect.  I cut and replaced 
with silence the first 2 seconds. I clipped the end off.
http://home.comcast.net/~richpeet/altbloop.mp3

Train
Sampled for noise reduction within the queit center section.  Applied 
to entire segment very hard. Set at 100% noise reduction level and 
reduction by 75 db. Then clipped both highs and lows tighter in order 
to minimize remaining artifact.
http://home.comcast.net/~richpeet/alttrain.mp3

Noise 97139
Determined the portion to sample for noise reduction and noted that I 
did not want noise reduction to include the very low frequencies with 
a constant tone. I did a fft filter cut below 100 cycles in the first 
segment and then sampled that filtered segment for the model in noise 
reduction.  I then undid the fft filter and applied the noise 
reduction to the entire segment very hard. 100% reduction by 75db. I 
then cut highs and lows tighter and clipped the end to reduce 
artifact.
http://home.comcast.net/~richpeet/altnoise97139.mp3

Whistle
Could not find a solution

Upsweep
Could not find a solution. 

These sounds will be removed from my server as examples of 
alternatives at the end of this week.  This is because they are not 
my files and I understand I really don't have permission to post them.

Rich Peet




--- In  "Anthony Kirchgessner" 
<> wrote:
> In an attempt to get up-to-speed with my sound editing software, I 
> decided to use the sound files located here
> 
> http://www.pmel.noaa.gov/vents/acoustics/sounds_mystery.html
> 
> as a way of practicing to reduce background noise. I thought others 
> might find them useful, too.
> 
> These are a few of NOAA's "mystery sounds" and contain much "Sea 
> Hunt"-type noise. I found it a useful exercise to try to isolate 
the 
> mystery sounds from this noise. I had moderate success with all but 
> one of these file -- Upsweep.
> 
> Can anyone recommend any other sets of files for editing practice?
> 
> Incidentally, these sounds, isolated or not, would be fantastic for 
> that Halloween ambiance. Playing them out the front window of your 
> home will be a sure way to keep the youngsters at bay! I found 
> Slowdown to be particularly disturbing.
> 
> Cheers,
> Tony Kirchgessner



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