Apple Final Cut Express HD - Manual (Page 620)

620 Part VIII Audio Mixing
Example: Using Keyframes to Control Pan
Setting keyframes to change pan dynamically works the same way as it does with
levels. You need to set at least two keyframes to effect a change over time.
Changing pan over time is often done to achieve stereo effects such as making a car
sound zoom from left to right, or putting a particular sound effect on one side or the
other of a stereo image. You want the car sound effect in your edited sequence to
zoom from the left to the right to match the movement of an onscreen car. Here are
the steps you would take:
To set up a dynamic stereo pan using keyframes:
1 Open the car sound effect in the Viewer so you can see it in more detail.
2 Option-click the purple pan overlay at the beginning of the car effect’s waveform, right
before the car sound starts playing, to set a keyframe.
3 Drag the Pan slider all the way to the left, so that the sound starts playing out of the
left speaker.