[ARC5] NDRC & Aircraft Audio above 20,000 Ft

[Brooke Clarke]

Hi:

I've been studying the various projects by the National Defense Research Committee and came across a discussion of 
aircraft audio.
https://en.wikipedia.org/wiki/National_Defense_Research_Committee

In the book: /Scientists Against Time/, 1952, James Phinney, 3rd ed (Wiki 
<https://en.wikipedia.org/wiki/Scientists_Against_Time>) they mention the problems with the microphones and earphones at 
high altitude and that throat mikes were poor above 20,000 feet.
Also speakers and common headsets did not work well and were replaced by units that fit into the ear, maybe the HS-30.
http://prc68.com/I/HS30A.shtml

Is there information on what audio headsets and microphones were used at the start of W.W.II vs. what was being used at 
the end of the war in high altitude bombers?

PS Other web pages I'm working on related to NDRC programs:
China Lake patents (VT Fuzes and Sidwinder missile) in process
http://www.prc68.com/I/Submarines.html
http://www.prc68.com/I/Torpedoes.html (and naval mines, depth charges, hedge hog)
http://www.prc68.com/I/Sonobuoy.shtml (need to add MAD: Magnetic Airborne Detector (as it was called in 1946).

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

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