Working with Audio Tracks

Adjusting the volume of an audio track is a common task. And when you combine audio in any waymixing music, sound effects, dialog, and background soundsyou almost always need to adjust the relative levels of each sound to create a pleasing mix.

iMovie HD provides several ways to work with sound levels. You can reduce the volume of an entire sound clip. You might do this if you're mixing music with the sound of the surf, and don't want the waves to drown out the music.

You can also vary a track's volume level over time. When combining music and narration, you might want the music to start at full volume, fade when the narrator talks, then return to full volume when she stops.

The timeline viewer provides several controls for adjusting volume levels. Many of them are easier to use when you have iMovie HD display audio track waveforms. To display waveforms, choose Show Audio Waveforms from the View menu.

A waveform looks a bit like the penmanship of an earthquake seismograph. Back-and-forth lines indicate the intensity of the shakingin this case, of the sound wave. Being able to see your sound instead of just a horizontal colored bar is a big help when trimming audio tracks, adjusting volume, and creating audio fades.

Adjusting the Volume of a Clip

To adjust the volume of an entire audio clip, select the clip and then drag the volume slider located below the timeline.

Fading Out or Fading In

Creating an audio fade involves working with volume markers in the timeline.

Step 1.	Choose Show Clip Volume Levels from the View menu.
Step 2.	Click the horizontal line in the audio track to create and adjust volume markers. Conversely, to create a fade-in, drag the beginning point of a volume marker all the way down, then drag the end point up.

Adjusting Volume Over Time

Here's how to adjust a track's volume level to accommodate narration or dialog in another track.

Step 1.	Choose Show Clip Volume Levels from the View menu.
Step 2.	Click on the audio track's volume level bar at the point where you want to adjust the volume. A volume marker appears. Can't trim clips? Turn off levels. If iMovie HD isn't letting you use direct trimming to adjust the in- and out-points of clips, it's probably because you're viewing clip volume levelsdirect trimming isn't available when levels are displayed. Be sure that the Show Clip Volume Levels command in the View menu is unchecked.
Step 3.	To lower the volume, drag the marker down. To increase the volume, drag the marker up. To move the point at which the volume changes, drag the marker left or right. To delete a marker, select it and press the Delete key.
Step 4.	When you've finished tweaking volume levels, choose Show Clip Volume Levels from the View menu again so that the command is unchecked.