Using Audio Pan and Fade Controls
When you expand the audio tracks, the fade and pan controls are revealed. Clicking the red fade button displays a red line, or fade control (Figure 10); clicking the blue pan button toggles to the blue line, or pan control (Figure 11). You can fade and pan the audio by altering the position and slope of these lines. You do this by adding a control point, or handle, to the line and dragging it to a new position. The line slopes up or down to represent the fade and pan. Every clip has a handle at its beginning and end, but you can add an unlimited number of handles in between for precise control of the audio.
Figure 10 Clicking the red fade button reveals the red fade control.
Figure 11 Clicking the blue pan button reveals the blue pan control.
The red line, or fade control, controls the level of the audio clip. By default, the line appears in the middle of the clip, at the normal gain level of 100. You can drag a handle anywhere from 0 (silence), at the bottom of the clip, to 200 (twice the volume), at the top of the clip (Figure 12).
Figure 12 Volume levels are measured vertically in the expanded audio clip--from 0% at the bottom to 200% at the top.
When you adjust audio levels, follow the principle of subtractive mixing. In subtractive mixing, you favor reducing (subtracting) gain levels over increasing them. First, establish a strong, representative audio level for the program (such as the standard level for dialog). Then, if necessary, decrease the gain of a clip in relation to others. Increasing a level in relation to other clips often leads to successive increases. Adding gain increases not only the signal (the sounds you want), but also the noise (the sounds you don't want, such as buzz and hiss), and can introduce distortion.