Tremolo is the technique of sustaining (actually rearticulating) a note with fast, controlled alternate picking (not to be confused with amp tremolo, which varies the volume). Tremolo originated as a way to maintain notes on acoustic stringed instruments beyond their natural decay time to emulate the long, sustaining notes of the human voice or a wind instrument. While the electric guitar offers other options for sustaining a note, tremolo picking a simple melody gives it a kinetic quality that can transform it into something energetic and memorable and create a virtual “wall of sound.”