by simer4 » Mon Feb 04, 2013 10:52 pm
The Doppler effect is when a sound sounds higher pitched when it is moving towards you, and lower pitched when it is moving away. Echoes do not have the Doppler effect in real life. Say a train is blowing it's horn in a valley. The sound coming out of the horn will sound higher pitched as it moves toward you at a high speed, however, the echo that bounces off the mountain walls will sound lower pitched than what you hear coming from the train itself. It's pitch is unchanged by speed. For an example of what I mean, take a listen of these horns being blown in a forest. Listen to the clearly pronounced echo on approach and when the car is driving away:
https://www.youtube.com/watch?v=hBE26jbQeFo
They exist everywhere. You may not see them, but they're there. Awww yeeeaaaahhhh, 20% Cooler! /)