: The Vocalist Live 4 directly analyzes the notes and chords you play on your electric or acoustic guitar through its guitar input.

Before the Vocalist Live 4, most harmony pedals required the user to manually select a key and scale. If the song moved to a chord outside that scale, the harmonies would sound "sour" or robotic.

According to the Official Owner's Manual , the device is designed as an all-in-one performance workstation. Owner's Manual - Strumenti Musicali