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Old December 19th, 2007, 01:50 AM   #1
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Directivity Factor/Index for Shotgun Mics

What are the directivity factor/index values for short shotgun and for long shotgun mics? I can't find this figure mentioned anywhere for shotgun mics. If a typical shotgun is equivalent in directivity to a 2nd-order super-cardioid, then it would be around 2.8 according to http://books.google.com/books?id=fcO..._CLk#PPA109,M1
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Old December 19th, 2007, 04:20 AM   #2
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check http://www.microphone-data.com/ for, um, microphone data ... includes polar patterns with gain/distance for various frequencies.
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Old December 19th, 2007, 04:38 AM   #3
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Mike, I've looked at that website already.
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Old December 19th, 2007, 01:57 PM   #4
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Using the term "distance factor" rather than "directivity factor" or "directivity index" produces more results.

This article is mainly interested in speech intelligibility and finds short & long shotguns to have a distance factor of about 3.

http://www.canford.co.uk/blueprinton...3/bigears.aspx

I presume the lack of a difference found between the short & long shotgun was due to the speech frequency range used and the interest in reducing the reverbant sound level rather than say unwanted low-freq traffic noise pickup. STI (Speech Transmission Index) was the used as the measurement.
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Old December 19th, 2007, 02:11 PM   #5
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Douglas Spotted Eagle, in this article, gives the distance factor of a line mic as 2.5.

http://presentation.digitalmedianet....hear_that2.htm
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