Andrew,=0D
=0D
You are correct for the most part. The gain curve starts at 200Hz on our Pr=
o Mono, and the curve is as I stated earlier. Applying a parabolic EQ will =
always improve the accuracy of a recording, which also needs to include dis=
tance to the source. Sometime in the future we will have a better article o=
n the application of EQ correction for parabolic microphones. We have been =
just crazy busy. Again, it is very rare for people to apply the EQ. The boo=
ster disks don't change the normal parabolic gain of 6dB/octave. The booste=
r disks do nearly eliminate what we call bass dip, which is the 4-8dB drop =
in gain, from the normal 6dB/octave gain curve, in the 500-1000Hz range. On=
your question on directivity, the parabolic microphone is a very direction=
al microphone, and the polar response is shown on our website. At lower fre=
quencies it is not as directional, but it starts being directional at aroun=
d 500Hz.=0D
=0D
One of our customers sent us those India leopard recordings. The stereo sam=
ple had an EQ applied as described in our manual. The mono parabolic sample=
had no EQ applied. In fact, none of our parabolic samples have had a EQ ap=
plied, except for a 200Hz high pass to get rid of rumble. I should note tha=
t in our stereo unit, the stereo microphones are outside the parabolic foca=
l point and the parabolic reflector has little influence on them. There are=
an extra set of microphones for picking up a background stereo field. The =
Mono output is the parabolic microphone.=0D
=0D
It should be noted, that parabolic microphones are designed to be able to p=
ick up distant sounds that would not be possible using any other microphone=
. That is why they are so often used in wildlife fields and distant voice a=
pplications. It is not always possible to be a couple of feet away from a s=
ubject.=0D
=0D
Bruce Rutkoski=0D
Owner=0D
www.wildtronics.com=0D
=0D
=0D
---In <> wrote :=0D
=0D
Dear Bruce, =0D
=0D
Thanks for all your replies on this interesting topic. =0D
=0D
=0D
Just so I have understood this correctly. A mathematically well designed l=
arge (your largest sized dish I mean) parabolic dish with an appropriate mi=
c correctly positioned that has a frequency response starting at say 30hz, =
will still record low frequency sounds eg the growls of a Gutteral Toad htt=
ps://soundcloud.com/bwanakomba-1/bbc-outlook-cut https://soundcloud.com/bwa=
nakomba-1/bbc-outlook-cut which start at 370Hz or other even lower sounds,=
will deliver no effective gain until you reach @1khz. Therefore one can s=
till record animals with low frequency calls its just that you won't get th=
e gain. So if the call has a range of 350Hz - 2.5Khz will the recording be =
very distorted and require alot of EQ due to variable gain curve, to make a=
n accurate reproduction? Is this where your booster disks come in, to prev=
ent the so called ' bass dip' and accommodate these frequencies into the re=
cording without distortion. Further if low frequencies enter from all angl=
es how acoustically transparent is the material to allow them in. =0D
=0D
=0D
I really liked your Indian leopard recording and wondered what the sonogr=
amme looked like or https://soundcloud.com/wildtronics-llc/stereo-leopard-1=
-india https://soundcloud.com/wildtronics-llc/stereo-leopard-1-india and wh=
at the frequency range recorded was. =0D
=0D
=0D
Cheers=0D
=0D
=0D
Andrew=0D
=0D
=0D
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