About audio waveforms
Audio waveforms are visual representations of the actual sound. Audio waveforms appear in clips in the following ways:
As the bottom portion of a video clip, colored blue
As a detached or an audio-only clip, colored green
An audio waveform’s amplitude and length change according to the underlying sound’s volume and duration. A short, loud sound such as a drum beat has a sharp, peaked waveform, whereas low-level crowd noise has a lower, more uniform waveform. These properties make it easier to find specific edit points when trimming clips or keyframing effects.
In Final Cut Pro, audio waveforms change according to a clip’s volume level or applied effects. The waveform appears larger when the volume is high and smaller when the volume is low.