Fading Audio Into or Out of a Clip
To fade audio into or out of a clip:
Move the vertical focus point inline with the relevant audio track.
Navigate to the beginning (or end) of the segment.
Click the Transition button.
In the Audio Transitions tab, enable Fade.
An audio transition is applied to the audio segment.
Adjust the length of the fade.
The audio is now fading into (or out of) the clip.