Audio Fade in and out, without the click

A fade is one of the few edits a listener should never notice. Done well, it tells the ear "this is over" without drawing attention. Done badly, it sounds like the volume knob was turned by hand — because that is essentially what it is.

Why a hard start or stop clicks

Digital audio is a series of samples. If a file begins at full amplitude, the very first sample jumps from zero to a large value, and that jump is a click. The same happens at the end. A fade of even a few milliseconds removes the jump. For speech, 150–300 ms is enough; for music, use something you can hear as a musical gesture rather than a technical fix.

Length is a language

A 0.2-second fade says "this is a clip". A 2-second fade says "this is an intro". A 6-second fade says "this is the end of a song". The length is not a technical parameter; it is the message. Match it to the context instead of using the same value everywhere.

Curves, briefly

The linear curve changes amplitude at a constant rate. The smooth S-curve changes slowly at both ends, which hides the start and the finish. The exponential curve stays quiet and then arrives fast. For music, smooth is almost always right. For effects and stingers, linear is easier to time. Exponential is useful when the first part of a recording is noise that should not be heard.

Fades on loops

A loop has two edges that meet. Fading both edges makes the seam less obvious, but it also dips the volume every time the loop restarts. The better fix is to cut the loop at a zero crossing and use very short fades — 5–20 ms — so the dip is inaudible. For longer crossfades, use the audio merger, which can blend two tracks into each other.

Fades in video

If the audio belongs to a video, fade the sound before you export the video, not after. Most editors can do it, but a clean pre-faded audio track avoids surprises when the editor applies its own fade on top. Keep a WAV copy for the edit and an MP3 for review.

One last habit

Listen to the first and last three seconds on a phone speaker. That is where fades fail: a fade that sounds elegant on headphones can end before the room tone does, leaving an abrupt silence. The ear notices the silence more than the fade.