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Editor's note: Thanks to Scott R. Garrigus at DigiFreq for giving permission to reprint the following article. Visit DigiFreq for more great music technology tips & techniques.

DFreqTIP - Do the Doppler with Sound Forge

by Scott R. Garrigus

Sound editing applications like Sound Forge provide many different processing functions. More often than not, we as musicians don't usually venture past using these functions for their intended purposes. But if you are inclined to experiment, you can open up a whole new world of musical possibilities. One such situation is in the combination of a number of different functions to achieve a single effect. An example might be the Doppler effect.

At some time in your life, you've probably noticed that if you are standing on the side of a road and a car passes by that is either blasting loud music or blaring its horn, the sound changes in pitch. This is known as the Doppler effect. For more information, go to:

To achieve the Doppler effect in Sound Forge, you have to process your audio using three different functions. First, to simulate the sound passing by you, use the Pan/Expand function as follows:

1) Select your audio data.
2) Choose Process > Pan/Expand.
3) Choose the Left To Right (Linear) preset.
4) Click OK.

Second, to simulate the sound getting closer and then moving away from you, use the Graphic Fade function as follows:

1) With your audio data already selected, choose Process > Fade > Graphic.
2) Set the Maximum Gain parameter to 100%.
3) Click the Reset Envelope button.
4) Move the beginning and ending envelope nodes to 50%.
5) Add a node to the middle of the envelope and set it to 100%.
6) Click OK.

For the final touch, use the Pitch Bend function to simulate the Doppler effect as follows:

1) With your audio data already selected, choose Effects > Pitch > Bend.
2) Set the Semitones parameter so that the graph range is set as +1 to 0 to -1. If you want a more dramatic effect, set the range as +2 to 0 to -2.
3) Activate the Preserve Original Duration option.
4) Click the Reset Envelope button.
5) Add a node to the middle of the envelope (at the center vertical line) and set it to +0.5.
6) Add another node to the envelope at one vertical line to the right of the center. Then set this node to -1 (or -2).
7) Set the ending envelope node to -1 (or -2).
8) Click OK.

When you play the audio, it should originate at half of its volume in the left speaker. Then it will gradually pan to the right speaker getting louder and slightly higher in pitch as it gets to the center of the stereo field. As it passes the center, its pitch will drop and it will move toward the right speaker with its volume getting gradually lower.

This may not seem like a very musical effect, but it might actually work quite nicely in a pop or rock mix on a distorted guitar part or a weird background vocal. You have to try things that are out of the ordinary if you want make interesting music.

Scott R. Garrigus - Author of Cakewalk, Sound Forge, and SONAR Power! books; Publisher of DigiFreq. Win a free copy of PlayPro Interactive Guitar and learn more cool music technology tips and techniques by getting a FREE subscription to DigiFreq... go to:

Copyright © 2002
Scott R. Garrigus
Reprinted with permission.