There's also an issue with the complex "comb filtering" created by
reflections inside the dish which seems to be less with cardioids than
omnis. If the focus/microphone is inside the edge of the paraboloid,
much of the (higher Hz) lateral noise is excluded by the dish itself,
even using an omni.
I don't know about the self noise of the AT3031 (is it as good as
reported for the 3032 omni?). But in the under $200 range I would
suspect the trade off between omni/cardioid and cost/self noise of the
mic would be pretty close.
I now know several people who swear that expensive cardioids are better
in parabolas than (affordable) omnis, and others who make fantastic
(envy producing) recordings with affordable/mid-priced omnis.
The problems with wind are significantly reduced with omnis and that
would decide the question for me.
Cheers!
Steve P
Rob Danielson wrote:
>
>
> At 11:27 PM -0700 7/1/07, umashankar wrote:
> >in theory, it should be an omni mic, but in practice, cardioids work
> >better. all you need to make sure is that it is a widish cardioid,
> >so it 'sees' the whole dish and not just a small part.
>
> Why would you generalize that cardioids are better? Maybe someone
> knows how much of a parabolic dish would be ideally covered evenly by
> each mic if stereo or by one mic if monaural.
>
> When I compare the polar patterns at 5KHz, the AT3031 Cardioid is
> down about 7dB at 90 degrees off-axis and the The AT3032 Omni is down
> about 3dB at 90 degrees off-axis:
>
> http://ad2004.hku.nl/naturesound/3031-32_Card_Vs_Omni_PolPat.gif
> <http://ad2004.hku.nl/naturesound/3031-32_Card_Vs_Omni_PolPat.gif>
>
> The rear rejection with a cardioid mic might be a good thing,
> especially for an monaural parabolic dish? Rob D.
>
> = = = =
>
> >
> >umashankar
> >
> >
> >i have published my poems. you can read (or buy) at lulu.com
> >
> >
> >
> >----- Original Message ----
> >From: no_mas_films <
> <NoMasFilms%40comcast.net>>
> >To:
> <naturerecordists%40yahoogroups.com>
> >Sent: Monday, July 2, 2007 9:45:18 AM
> >Subject: [Nature Recordists] Cardioid Vs. Omni for use in Parabolic
> >mic setup...
> >
> >
> >Recently I asked the group to recommend a good relatively low cost
> >microphone for use in the 22" parabolic mic setup I am building. I was
> >suprised that one of the mics was a omni (the AT3032)... now I AM
> >truely confused as I was under the impression that a cardioid would be
> >better by rejecting sound from anywhere other then the focal point of
> >the reflector. Please share your expertise with this newbie! Help!
> >Thanks, Chris
>
>
>
>
>
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