300
What is the Envelope Tool ?
The _____ gives you detailed control over how tracks fade in and out, right in the main track window. When it is selected, the amplitude envelope of each track is highlighted in a green line, with control points at the beginning and end of each track. To change a control point, click it and drag it to a new position. To add a new point, click anywhere in the track where there is not already a control point. To remove a point, click on it and drag it outside of the track until it disappears, then release.