Audio keyframes are adjusted inside the audio track itself using the “rubberbanding” technique.
Basically, drag keyframes up or down to raise or lower volume and alt drag to move keyframes left or right.
http://www.premiumbeat.com/blog/audio-keyframing-tips-in-avid-media-composer/
When editing audio in Avid Media Composer, you adjust the audio gain within segments in the Timeline by adding and adjusting keyframes—a process called rubber banding. This process is often a meticulous task, so it’s useful to be able to use as many streamlined techniques as possible, since accurate audio editing is such an essential part of the post production process.
