I thought i had already made this video once, but i was unable to locate it, so i just made a new one :) Hope this helps someone, i get asked all the time "how do I lower the volume of my bass so the kick drum can be heard" This tut will show you how to do that using the fruity peak controller, there are other ways of sidechaining using compression etc, and in FL 8.5 sidechaining is built in, but that will be another tut.
Ducking Using The Fruity Peak Controller