Apple Final Cut Pro 7 - Manual (Page 988)

4 Press I to mark an In point, press the Right Arrow key on the keyboard to move forward
one frame, then press O to mark an Out point.
In and Out points for
the single-frame clip
5 Drag this clip from the Viewer to the first frame of your sequence in the Timeline.
6 Option-click the video portion of the one-frame clip to select that part only.
Select the video only,
then press Delete.
7 Press Delete to delete the video portion of this clip.
Only the audio
portion remains
as your sync beep.
Note: Instead of deleting the video portion of the two-pop, you can also replace it with
a more appropriate video generator, such as a circle shape generator.
988 Chapter 60 Exporting Audio for Mixing in Other Applications