Pro Tools | First calculates fades and crossfades in RAM in real-time. You can quickly and easily apply a fade-in or fade-out on a audio clip, as well as apply crossfades between adjacent audio clips. Crossfading is the process of fading between two clips of audio to prevent pops, clicks, or sudden changes in sound. Crossfades have many applications, from smoothing transitions between clips to creating special audio effects. The crossfade duration, position, and shape are all user-definable.