Next, make the text appear more lively by animating its Hue property with the audio keyframes. In the Timeline window, expand the text layer and choose Fill Color > Hue from the Animate pop-up menu in the Switches column. Then, choose Animation > Add Expression. Drag the pick whip to the Both Channels slider to animate the Hue property using values from the audio keyframes. Then, type *10 (or a different value) at the end of the expression.

As you preview, note how the size and color of the text change as the volume of the audio changes. To add more interest, experiment with different types of music, create additional text layers, or add a background layer to your composition.

This is just one example of what you can do with audio amplitude keyframes—and only a fraction of what you can do with expressions! For more ideas on using these fun features, see the After Effects online Help.