About a year ago I challenged myself to create a system in After Effects that would drive elements based on the pressure levels of the different frequency ranges of an audio file.

I forbade myself from using any 3rd party plugins, which meant that it would be necessary to do my own scripting.

The result of this challenge was this script which you can find on GitHub which I've released under the MIT License.

The two videos below both use this script to drive different elements. 

The first one uses the script to drive masks that cover or reveal the volume bars.

For the second video, each of the columns were rendered separately in Blender. Each column is animated over 100 frames going from short to tall, effectively giving each frame a percentage value. My visualizer script, then, is used to time remap each column to a distinct frame based on the pressure level of that particular frequency.