How to use sound in Blender

(Another Memo To Self production.)

The 3D modeller Blender has become a Jack of all trades during its long existence and as such, questions about the program that once had a single, simple answer because of the limited scope of the problem domain have now become an exercise in writing proper Google queries.

Simply put: when I wanted to know if I could use sound in Blender, the answer was yes and then I knew even less.

Here are the ways you can use sound in the graphical program Blender, with some links to more information.

Soundtrack for video editing
Blender has a built-in video editor. This just takes streams: audio, video, both. Works like any video editor, except in Blender’s hard-to-fathom way.

This requires the video editing tab, see the link in the next entry.

Soundtrack for keyed animation
If, say, you are making a 2D cartoon, which Blender lets you do, it is not uncommon to start with the voice acting and draw the cartoon based on your soundtrack.

Blender uses the exact same tool as in the first entry and the only reason I give it its own entry is because it is part of a completely different work-flow and you might not realise you need to use the same tool for that.

Animator Worthikids has a 90 minute tutorial on How To Make A Cartoon, the first 7 minutes of which discuss audio. Don’t forget to check out his work (same Youtube channel).

Sound as a ‘driver’
You can influence animation with the volume of sound, the same way disco-lights work. A simple example would be a series of bars that get taller as the sound gets louder and shorter as it gets softer.

Since this is an easy but impressive effect, there are a ton of short tutorials on Youtube that show you how to achieve this.

You implement the effect in the graph editor using the menu Key / Bake sound.

When people say “almost any value in Blender can be animated”, this is what they mean, and the graph editor is often the place where you work with the animation of values, whether they represent shapes, colours, movements, sizes, textures, rotations and so on.

Ducky 3D: Make Anything React to Music

Make sound as the camera approaches an object
An obscure use of sound in a 3D program, but coincidentally the one I was looking for, is adding a sound to a mesh (a 2D or 3D object). What good is that, you wonder? Well you could use it to add environmental sounds. If leaves rustle, don’t just show it but also produce the sound.

An interesting use case is if you needed to add spatial sound to an existing video.

A more general tutorial.

Are there other places where sound has managed to sneak into Blender? Let me know in the comments.

What I was really looking for, by the way, is sound that responds to an action, sound that is driven by the graphics instead of the other way around. Let’s say your protagonist flips a switch, you want the switch to make a sound. You could key that, but every time you move the flip, you would have to both re-key the visuals and the audio, which sounds (ha!) like a chore.

I am not sure (not being an animator) if this would be more than just a convenience for the initial stages of your animation project, but it is something I can use for my little hobby projects.

(Yes, you guessed right, laser rays pointed at the moon.)

Blender, however, doesn’t currently seem to support triggering sound.

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