Fixture Control Tracks:
Fixture Control Tracks let you control individual fixtures by overriding the Main Track.
This is helpful if you want to control fixtures independently of the Main Track.
For example, you might want some Par Cans to be a different color or you might want a couple of moving heads to position themselves differently from the rest. Fixture Control Tracks make this easy, as they allow you to customize any audio file in your music library for a particular venue or lighting rig.