Add a fade in and a fade out to audio

To fade a song in or out, select its first or last few seconds, choose Effects ▸ Amplitude ▸ Fade In… or Fade Out…, pick a curve and click OK. The fade lasts as long as your selection. Auditius does it in your browser, for free, and your audio is never uploaded.

The Amplify / Fade window in Auditius with the Fade Out (to -60) preset, over the selected last seconds of a song's waveform
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How to fade audio in and out, step by step

A fade applies to the selection, so what you select decides how long the fade lasts.

  1. Click Open a file to fade, or use File ▸ Open… (Ctrl+O), and choose your audio file.
  2. For the fade in, drag from the very start of the waveform to the point where the sound should reach full volume.
  3. Choose Effects ▸ Amplitude ▸ Fade In…, pick a Curve and press Preview. The window shows the length of the selection next to Applies to.
  4. Click OK to apply it.
  5. For the fade out, drag from where the fade should begin to the very end of the file, and use Effects ▸ Amplitude ▸ Fade Out… in the same way.
  6. Listen to both ends, then save the file with File ▸ Save As… in the format you need.

Choosing the length and the curve

Two to five seconds suits the start of most songs, and a fade out at the end is often longer. A few milliseconds is enough to soften a click at a cut.

Fade In and Fade Out offer four curves: Linear, Logarithmic, Exponential and Cosine (S-curve). They matter most on long fades: preview a couple and keep the one that sounds smooth.

  • Linear changes the level at a steady rate. It works well for short fades and clicks.
  • Cosine (S-curve) starts and ends gently, which suits musical fades.
  • Logarithmic and Exponential bend the fade one way or the other. On a long fade out, try both and listen to how quickly the end disappears.

More control with Amplify / Fade and Envelope

Effects ▸ Amplitude ▸ Amplify / Fade… ramps the level from Initial Amplification to Final Amplification, anywhere from -60 to +30 dB, along a Fade Curve. Its Fade In (from -60) and Fade Out (to -60) presets are ready-made fades, and you can combine a fade with a change in level, such as fading in from -60 dB up to +3 dB.

Fade In and Fade Out go all the way to silence. The Amplify / Fade presets stop at -60 dB, which is very quiet but not silent.

For a fade with several stages, such as lowering music under a voice and bringing it back, use Effects ▸ Amplitude ▸ Envelope… and draw the curve, or start from its Fade In, Fade Out or Duck Middle shapes.

Fades in the Multitrack view

In the Multitrack view, fades belong to the blocks and do not change the file. Hover over a block or select it, then drag the small square at its top left or top right corner inward. For exact lengths, open Edit ▸ Block Properties… and type Fade In (s) and Fade Out (s). These fades are linear.

To blend one song into the next, turn on Options ▸ Automatic Crossfades and overlap two blocks on the same track. Export the result with File ▸ Export Mixdown… when you are done.

Frequently asked questions

How long should a fade out at the end of a song be?

Three to ten seconds is common for songs, one or two seconds for a podcast intro or outro, and a few milliseconds to hide a click. Select that length and apply the fade.

Does a fade in start from complete silence?

With Effects ▸ Amplitude ▸ Fade In… and Fade Out…, yes: the outer edge of the selection is silent. The fade presets of Amplify / Fade go down to -60 dB instead, which is almost, but not entirely, silent.

Can I change a fade after applying it?

In the edit view the fade is written into the audio, so undo it with Ctrl+Z and apply it again with another length or curve. In the Multitrack view, block fades can be changed at any time by dragging their handles.

How do I crossfade two songs into each other?

Send both files to the Multitrack view with Edit ▸ Insert in Multitrack (Ctrl+M), turn on Options ▸ Automatic Crossfades and move the second block so its start overlaps the end of the first on the same track.

Can I fade out just one channel of a stereo file?

Yes. Choose Edit ▸ Edit Channel ▸ Left Channel or Right Channel, then select and apply the fade as usual. The effect window shows which channel it applies to.

Audio tools