impedance and empericism

JIMRPT@AOL.COM JIMRPT@AOL.COM
Sat, 17 Jun 2000 23:39:29 EDT


In a message dated 6/17/2000 10:42:40 PM, Ric wrote:

<<Hmm interesting--I suspect that when sound waves hit a temperature
differencial that they refract just as light does--and I seem to rememeber
that does affect frequency. I could have just imagined that--anyone know
for sure?>>

Ric;
 Absolutely on both counts. In water this phenomenon is called a 
"thermocline" and is used constantly by submarines to hide their location. 
The sound  from a sub on one side of a thermocline will be either reflected 
back to the same side it originates from or it is "shifted" as to make the 
apparent location appear different than it really is. Frequencies going from 
colder to warmer water tend to shift upward in pitch and from warmer to 
colder lower in pitch.  This is true in the world of sonar at any rate. There 
is a name for this stuff but I can't remember that right now.....probably 
three o'clock this morning though!
Jim Bryant (FL)


This PTG archive page provided courtesy of Moy Piano Service, LLC