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Name: Glenn
Status: educator
Age: 60s
Location: N/A
Country: N/A
Date: 1999 


Question:
Why do low pitched sounds travel farther than high pitched sounds?


Replies:
One reason is the different wavelengths. Low pitched sounds have wavelengths of around 10 feet or more; high pitched sounds have wavelengths of around an inch or less. As sound travels through nonuniform air (pressure differences resulting from temperature differences and from wind; humidity differences resulting from puddles, animals breathing, trees, etc.) it's speed and direction vary by small amounts. Small changes in speed and direction result in a sound wave interfering with itself, and the extent of the interference depends on how the speed variations and pathlength differences compare with the wavelength. A path difference of a quarter of an inch could result in complete cancellation of short wavelength sound but would have a barely noticeable effect on long wavelength sound.

Tim Mooney



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