I have been following this thread for some time now. Very interesting
and informative. Now I have come to wonder if the varying perceptions of
the expected behavior of waves hitting a parabolic reflector are not
based on the varying ways we visualize waves. It is common practice to
illustrate sound waves using the familiar sine wave graph. While that
does help us understand issues of frequency and amplitude, it does not
help very much in visualizing how sound waves actually travel through
air or any other medium. I think it might be helpful to make the
distinction between transverse waves (which often tend to look
sinusoidal) and longitudinal waves (which are a little harder to
illustrate easily). Here are a couple of sites that I find helpful in
the visualizations.
http://www.gmi.edu/~drussell/Demos/waves/wavemotion.html
http://www.cbu.edu/~jvarrian/applets/waves1/lontra_g.htm
Jim Lee
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Jim Lee
http://www.bambooturtle.us/
919 682 5853
audio art, gourd sculpture,
lighting design, and forensic audio
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