PDF (adobe.com)

Precisely fade in or out

  1. At the far left or right of the waveform, drag the Fade In   or Fade Out  handle inward.
  2. (Optional) To change from the default, linear fade, drag up to create a quick, smooth logarithmic fade, or drag down to create a long, smooth exponential fade.
If you save files in ASND format, fades remain adjustable and appear in multitrack clips.
Drag up or down to change the fade type

A.
Quick, logarithmic fade

B.
Long, exponential fade