How to Fade Audio In and Out in After Effects: A Step-by-Step Guide
Learn how to fade audio in and out in After Effects using audio level keyframes, plus tips for syncing fades to visuals and avoiding common audio mistakes.
Audio fades are the difference between a cut that feels abrupt and one that feels intentional. In After Effects, audio lives on layers just like video, and you control it with the Audio Levels property and keyframes. It is a simple technique that dramatically improves the polish of title sequences, promos, and motion graphics. Here is exactly how to fade audio in and out in After Effects, plus the mistakes that trip up most editors.
1. Where audio lives in After Effects
In After Effects, audio is attached to a layer, usually as part of an imported clip. The property you control is called Audio Levels, and it behaves like the volume slider for that layer. The default is 0 dB, which is full volume. Lowering the value reduces the volume, and negative values go quieter still. You animate Audio Levels with keyframes, exactly like you would animate position or scale.
2. Fading audio in with two keyframes
A fade-in needs two keyframes on the Audio Levels property. Place the first keyframe at the start of the layer, where you want the audio to begin, and set it to a low value like negative infinity, or around minus forty decibels for a faster practical fade. Then add a second keyframe one to two seconds later at 0 dB. After Effects interpolates between the two values, creating a smooth rise from silence to full volume.
3. Fading audio out cleanly
Fading out is the mirror image. Put a keyframe at 0 dB where the fade should begin, then add a second keyframe before the layer ends at a low value so the audio reaches silence at the end of the clip. Choose the duration based on the content: a music bed can fade over two to three seconds, while a sound effect or voice clip usually fades faster, in under a second, to avoid dragging out the end.
4. Controlling the shape of the fade
The interpolation between keyframes matters as much as the endpoints. Right-click a keyframe and open Keyframe Interpolation to change the temporal easing. A linear fade sounds mechanical on music, while an eased fade, slowing down as it approaches silence, feels more natural. For precise control over the curve, switch the value to a bell-shaped exponential curve using the Audio Levels property's built-in curve. Audition the result, because the ear is the final judge.
5. Linking fades to visual moments
A well-timed fade is tied to the visuals, not to an arbitrary time. Match the audio fade-out to the moment the picture fades to black or the logo resolves, so the audio lands exactly with the visual. Use markers on the timeline to flag the visual beats, then snap your audio keyframes to them. When a scene change carries an emotional beat, a slightly longer, eased fade out after the change can feel more intentional than a cut.
6. Common audio fade mistakes and fixes
The most common mistake is fading to a value that is not silent, leaving a faint hiss or hum at the start or end. Use a very low value or negative infinity for true silence. Another is overusing fades on every clip, which makes a cut feel slow; use hard cuts for rhythm and fades for transitions between distinct moments. Finally, preview with speakers or headphones at a consistent volume, because judging fades at different monitor levels gives unreliable results.
FAQ
Can I fade audio in After Effects without keyframes?
Keyframes on the Audio Levels property are the standard method. If your clip is a video layer, you can also enable an audio fade via the layer's audio properties, but keyframes give you the most precise control over timing and curve shape.
What is the best fade duration for music?
For music beds, two to three seconds is a comfortable fade that feels natural. For short sound effects and voice, under one second keeps the pacing tight. Always match the duration to the content and the visual edit rather than using a fixed value.
Should I fade audio in After Effects or in a dedicated editor?
For quick fades inside a composition, After Effects is perfectly fine and keeps everything in one place. For long-form projects with complex audio, a dedicated audio or video editor gives you better waveform view, more track control, and easier mixing.