The dynamic filter effect is triggered by pick attack. The harder you pick the string, the louder the effect. The Sensitivity control allows for frequency adjustment of the effect. Lower settings provide for a lush, smooth feel ideal for locking in with a drummer and providing solid low-end. Higher settings provide amore expressive effect that is ideally suited for lead breaks. Play around with it and you will find that there are a lot of possibilities as the effects volume and sound is mainly produced by your pick attack! The Heart Attack can be placed in the signal chain before or after a distortion, but usually sounds better when placed after. If using multiple pedals such as delays and other modulation effects, try the Heart Attack in different parts of the signal chain until you find the sound you personally prefer.