Apple Final Cut Pro 6 - Manual (Page 916)

Chapter 6 Mixing Audio in the Timeline and Viewer 131
I
To set and adjust subframe audio level keyframes:
1 Open the clip in the Viewer and click the Audio tab.
2 Move the playhead to the edit point that’s causing the click by pressing Shift-I or
Shift-O, or by using the Up and Down Arrow keys to move from one sequence edit
point to the next.
3 Zoom in to the clip as far as possible.
4 Hold down the Shift key as you drag the playhead to the exact place where the
click occurs.
When you’ve zoomed
in all the way, the
playhead in the Viewer
is the width of one
video frame.