How to Create Sound in After Effects

This tutorial is brought to you by creativecow.net.

Hey, this is Aaron Rabinowitz for creativecow.net. There have been a lot of posts related to audio lately, so I’d like to take a few moments to talk about working with audio in After Effects. In fact, maybe I’ll just do this entire podcast with no visuals at all. Yeah! Okay, I'm just kidding.

All right, first of all, let me get this out of the way. If your audio sounds great in After Effects but sounds distorted or clips when you output, it’s probably because you used an MP3 file. Do not, I repeat, do not use an MP3 file in After Effects, they don’t work. They seem like they work but they don’t.

So, the next time you’re going to put an MP3 file into After Effects, listen to that little voice in your head shouting, “Danger, Will Robinson. Danger,” and then go rebuild your audio as a WAV file or some other uncompressed format. Now one thing people ask about is audio previews. A lot of people don’t realize that they can play back their audio without RAM previewing. To listen to your audio, hit the period key on the number pad and the audio will play back from the time markers positioned in the timeline. Hit the period button again to stop the looping preview.

Now, by defaults, After Effects will play 10 seconds of audio. However, if you need to hear more, you can change this amount to something else by choosing edit, preferences, previews. In the preferences dialog in the audio preview section, you can change this amount to whatever you need. There maybe a negative effect from adding in more time here, but I haven’t seen that. You’ll have to try it for yourself.

But speaking of slow downs, if you’d ever try to RAM preview a long animation that has audio, you’ll notice that After Effects appears to just sit there for a few moments before it starts to catch the video frames in the RAM. That’s because it catches the audio first. If you’re only interested in previewing the video, you can either turn off the sound for your audio layer by using the layers audio switch or you can choose composition, preview and then click on the work audio to uncheck it.

When you’re ready to re-enable the audio preview, just go back and do the same thing, composition, preview, audio. You will also notice there are other audio options such as audio preview here forward, which is the same as hitting the period key and audio preview work area which plays the audio found in the current work area of your composition.

Now if you want to preview your audio frame by frame, such as you might have to do if you were lip synching, you can drag the time slider down while holding down the control key on windows or command key on the Macintosh and your audio will play back frame by frame as you scrub.

One really cool and useful thing that you can do with audio is mark off a selected layer in real time as the audio plays back. So select the layer that you want to mark and it can be more than one and then hit the period button on the number pad which will get your audio playing. Then while it’s playing back, hit the asterisk button on your number pad and it will add markers to the layer. You won’t see those markers until after you stop the preview, but when it’s done, they’ll be there.

I’ll warn you that the markers are usually one to two frames off from your original timing because of the amount of time it takes for the information to get from your keyboard to the processors and out to After Effects. But that’s a simple fix, just drag the markers down and preview the audio again to make sure everything lines up properly. By the way, this whole thing works with RAM previews as well. And you don’t have to preview at all to add markers, just go to the point in time that you want to add a marker and with the layers selected, hit the asterisk key.

Now, I show this tool to people and often they ask me, “Come on. How useful is that really? Do you actually use layer markers for your audio?” I always answer that no matter what the projects, if there's audio in it, I have markers always. There’s no better way to mark off timing for different effects and animation. It helps keep things organized and as you know from listening to this podcast, for me, that’s a big deal. And to keep things even more organized, after you have added the markers, you can double click on them and then in the marker dialog, you can add comments, and after you click OK, you can see those comments in the timeline. So all in all, markers are probably one of the most valuable tools at After Effects offers, at least for me.

Another great thing about audio is that After Effects allows you to see the audio with form. This can also be very helpful in marking off time. Select your audio layer and hit LL on your keyboard. That’s the letter L twice in quick succession. Being able to see your audio means you can get a much better idea of when certain events are supposed to happen. Maybe there's music with a symbol crash that you want to accent with animation or maybe the sound of breaking glass. Being able to actually see the sound wave means you know exactly when you need to have your animation or effects kick in. I do want to warn you that showing more than a few seconds of the audio wave form in the timeline can make After Effects run slowly. So make sure to zoom in a bit before revealing the WAV form, otherwise things may freeze up for a moments.

Now, if you’re one of those animators who likes to get real control of things and would like to work in the graph editor, you probably notice that unlike in the normal timeline view where you can see whatever you’ve got open there and that includes your WAV form. When you go into the graph view, things disappear including your audio WAV form. But if you select your audio layer and click on the graph options button and then choose show audio wave forms, then you can see the audio in the graph view. If you also select a layers property that you’re animating, then you can see both the graph, key frames and the audio. That can be pretty helpful in precision animation.

Now it’s not a perfect system because if you try to select a key frame from your video layer or image, it deselects your audio layer, making the WAV form disappear. But it’s better than not having it there at all, right? If you have made some changes, you can always reselect the audio to get a better idea of how things are laid out in time and what you might need to do to tweak your work. That said, if your audio and video are on the same layer, so like, you know, a video clip that has audio, then this isn’t going to be a problem because if you select any key frame property on your layer, then the layer remains selected, which means it’s audio wave form remains visible. For me, this isn’t usually the case. My audio and video are almost always on separate tracks. But maybe that’s not your situation.

Finally, one last thing that I would like to mention is the ability to convert audio to key frames. You can select your audio layer and choose animation, key frame assistant, convert audio to key frames. This creates a null object that contains expression controls with animation key frames, and what you can use to link to other layers and their animation properties. I have covered expression controls in my three part expression control tutorial and I’ve covered working with audio key frames in my two part tutorial on creating a custom WAV form. So check them out for more information.

As always, I hope this helps in the work that you do. Once again, this is Aaron Rabinowitz for creativecow.net.