Lowering a loud, unexpected background sound with manual keyframes

Keyframes are an essential tool to all aspects of video editing. Occasionally, we want to make adjustments not just to an entire clip, but within a clip. A keyframe is a kind of marker placed at a precise moment in time that locks in a value for a parameter. When a second keyframe is placed later on the same clip and a parameter value is changed, FCPX knows to animate the difference between the two.

The previous recipe, Lowering your music during speakers, was actually a special function of FCPX that automatically created four keyframes for us. But, sometimes you need to do a little bit of work yourself to achieve the right sound.

In audio editing, we often encounter scenarios where the clip's audio may be perfect with the tiny, but obnoxious exception of a loud, quick sound in the background; or perhaps when a speaker let out a large laugh that was much louder than the rest of his/her interview. We can use a few keyframes...