Apple Final Cut Pro 7 - Manual (Page 915)

3 Click the Record Audio Keyframes button (located in the button bar of the Tool Bench
window) to turn on keyframe recording.
4 Press the Space bar to begin playing your sequence.
5 Adjust faders and panning knobs on the control surface.
Audio level and pan keyframes are added to the clips in your sequence.
When you play back a clip or sequence, the faders in the Audio Mixer and the control
surface are automatically controlled by audio level and pan keyframes. Keyframe recording
begins when you touch the fader and finishes when you release the fader.
You can even adjust a fader to a new position while it is moving. For example, if a fader
on the control surface is slowly moving down from a 0 dB keyframe to a –60 dB keyframe,
you can move the motorized fader up to +12 dB, thereby creating new keyframes.
When you release the fader, it returns to its trajectory moving toward the –60 dB keyframe.
915 Chapter 56 Using the Audio Mixer