I will continue to run a no barrier parabolic with omni pair.
Reasons are simple. A Parabolic is a bad ambient mic so why would you
want the stereo background when you can use the pair as a noise cancel
pair and get considerable more reach and lower background noise than a
separated pair with barrier. Also, as soon as you use a barrier in a
parabolic the mic is no longer seeing the whole dish, just half.
Using the telinga dish as the starting point you are really already
over the edge on how big a parabolic should be for bird song.
Rich
--- In "John Hartog"
<> wrote:
> > > So in summary a parabolic, split mic, no barrier arrangement
> can
> > >out reach a parabolic using a stereo barrier with near spaced
> mics.
> > Reach is one of my goals but I also want a more natural
> > recording.
>
> I too have been experimenting with stereo 183s in a dish.
> First I mounted them spaced about 1" without a barrier, and It
> actually seemed to produce ok stereo for the subjects (frogs). I
> posted a clip, and Walt suggested the effect might be more
> panned mono than stereo, and I think Dan Dugan suggested the
> background sounds were essentially mono. I listened to it again
> and noticed the stereo field for the subjects seemed wider than
> for the background - kind of inside out.
> Another thing that makes me suspicious about that method is: I
> was playing with a Telinga dish by reflecting light onto a piece of
> paper ( a not very scientific experiment,) and I noticed that the
> focus (at least for the light from that lamp) was not very
> symmetrical - rather twisted and distorted.
>
> I switched to a very simple barrier of mounting the 183s on a
> tube - again spaced about one inch. This method seems to
> work ok, the subjects sound nice and the background sounds
> wider. The only thing is the background sounds get flip-flopped.
> I think this is because a sound from one side, let's say the right,
> reflects off the opposite side of the dish and into microphone on
> the left.
> Here's a of example using this method (Northern Shovelers - I've
> posted this once before - 940k):
>
> http://www.rockscallop.org/JH_Shovelers.mp3
>
> I wanted a system that kept the entire stereo image intact without
> a flip-flop so I decided to use a barrier large enough to block the
> sounds from one side from reflecting off the opposite side. I
> decide on using an old LP, because it is thin, fairly dense, and
> rigid and about the size I was thinking of. It seems to work well,
> preserving a wide background image while highlighting the
> subject, as in this recording (Western Meadowlark - I've posted
> this once before - 940k):
>
> http://www.rockscallop.org/JH_050226_WMeadowlark.mp3
>
> This method is also useful for isolating multiple subjects as in
> this recording of two frogs (Pacific Chorus Frogs - New - 163k)
>
> http://www.rockscallop.org/jh-183pblp-050430-pcfrogs.mp3
>
> All that being said, I mostly use my 183s without a dish using a
> tree as a barrier. I got the "tree binaural" idea from someone at a
> Nature Sounds Society workshop.
> -John Hartog
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