In this tutorial we’re taking a different approach altogether to create procedural motion graphics from an audio layer. It’s a little bit more work, but it gives you a wonderfully organic look that responds visibly to the audio and can work as the basis for many motion-graphics projects.

Instead of using a filter to get the audio levels, we’re going to create keyframes from the audio source and use these to power a couple of other effects; you won’t need any software beyond the standard After Effects filter tools to complete the project.

You will need to choose an audio file from your own library to work with however. We suggest something with a wide dynamic range for best results – Sam Hampton-Smith used AC/DC’s Thunderstruck for his version of the project.


Step 5
Locate the pickwhip for the Amplitude property and drag it down to the Audio Amplitude layer’s slider effect control. The values for the Audio need to be translated from the range produced by the audio to a range suitable for the wave’s amplitude, so we’ll change the expression that has been generated in the next step.


Step 6
The wave’s amplitude looks good between 1 and 2, and will work up to 5. We need to translate the values generated by the audio keyframes into values between 0 and 2 in wave amplitude. Change the expression to read:

x = thisComp.layer(“Audio Amplitude”).effect(“Both Channels”)(“Slider”); linear(x, 5, 10,0,2)

This maps values for audio between 5 and 10 to a wave amplitude between 0 and 2. If audio falls below 5, the wave is set to 0. If it’s 10, it’s set to 2.


Step 7
In the Effects and Presets panel, locate the CC Ball Action effect and drag it onto the solid layer. Twirl down the CC Ball Action effect settings, changing the Twist Property value to Brightness, and the Twist Angle value to 140º. This sets the 3D balls at a good angle to the viewpoint and shows the displacement caused by brightness generated through the Wave World effect.


Step 8
Finally, add an adjustment layer by choosing Layer > New > Adjustment Layer. Add a four-colour gradient by choosing Effect > Generate > 4-Color Gradient. Set the blending mode for this effect to Add and choose colours that suit your project for the four colour stops. Add a glow (Effect > Stylize > Glow) and do a RAM preview to see your audio come to life.

Sam Hampton-Smith

Who: Sam is a digital media designer who lives and works in Scotland. He writes regularly for UK magazines and teaches undergraduate multimedia at UHI. Away from work Sam has three small children, a piano, four guitars and one wife.
Software:
After Effects 7/CS3/CS4
Time to complete: 1 hour, plus rendering time
Contact: www.hampton-smith.com