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Re: Noise Reduction =A0Posted by: "Marc Myers" mmyers@primate.org=A0 Tu=

Subject: Re: Noise Reduction =A0Posted by: "Marc Myers" =A0 Tu=
e Sep=A016,=A02008 8:07=A0pm (PDT)

Mike
Some artifacts are inevitable but there are techniques to reduce them. No m=
atter what the bit rate your file was recorded, first increase it as much a=
s possible. More samples are better than few samples when you post process.=
 Before you apply DNR do you filter? a graphic equalizer or a couple of pas=
ses with parametric equalizer can be very helpful. Last, don't apply DNR al=
l at once. Better to make several passes as fairly low levels. Hope this he=
lps.
Marc
..........................................................

=A0

Danny,

=A0

I thought that this group, which I have been in for several years, would be=
 able to best handle the question. As a former audio dealer and broadcast=
=A0enginner, I am still struggling to learn about sound. I am not aware of =
a group that records animals other than NR, but if you can suggest a better=
 group to pose my problem,=A0such information would be appreciated.

Mike

...........................................................................=
..........=A0

Marc,

=A0

Thank you for your response.

=A0

My recorder is a=A0Tascam CD recorder--standard record rate. The bandpass o=
f interest extends to 8-10 kHz. A=A0shotgun microphone is at=A0one side, bu=
t that doesn't=A0help much. I thought by narrowing the aperture that would =
make a significant increase in the S/N, but it does not do so appreciably. =
The signal goes into a 30 band EQ that is set to enhance the frequencies of=
 the speech before recording. Part of the problem is that the body noise fr=
om cars and the low-frequencies of the speech signals are intertwined in th=
e spectrum below 100Hz.=A0I have used as many as five passes to attempt to =
get "perfect" results, but I just don't seem to be able to get a "clear" re=
cording.

The desired signal is at times significantly buried in the noise (I.e., S/N=
=3D -10dB or lower.). The original recordings are not a problem for me as I=
 have adapted , probably because of amateur radio and audio experience. All=
 the clarification efforts are to permit others to hear what I hear. I'm af=
raid that most of my clean up jobs haven't been successful.

Mike

P.S.: When you have a minute, please contact me directly.

=A0


=A0





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