
Sound Keys was first used to extract three separate streams from the bass region of the audio spectrum. Then three instances of 3D Stroke were used to create the "strings." Each has an animated path that describes a vibrating string. 3D Stroke's Path Time (found under the Advanced controls) was used to control the movement of the strings. Each has an expression where a sine function describes the general movement of the string. This is then multiplied by the stream that Sound Keys extracted, so that the strings appear to vibrate with their corresponding frequency.
Beat Explode
This example shows how you can link the output of Sound Keys to Trapcode Particular's Particles/sec setting. The effect causes particles to be emitted on each kick-drum beat. Note that you need good bass to properly hear the kick drum — a laptop speaker may not provide enough bass response.
Video Speed and Colors to Music
This video uses Trapcode Sound Keys to make the video play faster on the music beat. It uses Magic Bullet Looks to control the colors of the video based on the Sound Keys-generated opacity keyframes. View: Red Giant TV Episode 6
Video Speed to Music
This video uses Trapcode Sound Keys to make the video play faster on the music beat.
View: Red Giant TV Episode 5