The Vocalist Live 4 from Digitech is a three- or four-part vocal harmony generating floor pedal, that uses musIQ Harmony Technology for both note detection and harmony generation. The unit analyzes guitar chord progressions in real-time and generates the correct harmony notes, either a third or fifth, above or below the lead vocal.
Most harmonizers function based on the user inputting information into the unit that specifies a single key/scale setting. However, if a song moves out of the selected key, it is very likely that a wrong harmony note will be generated at some point. The Vocalist Live 4, on the other hand, works by analyzing the chords of the performer's guitar along with the vocal, and utilizing real-time processing, always generates correct harmonies, regardless of the overall key structure of the song.
No extensive programming is needed, other than specifying at what intervals above or below the lead vocal the harmonies will be generated. Fine tuning of the output harmonies is possible, along with the ability pitch-correct the main vocal. A built-in mixer provides control over the volumes of the constituent parts and an effects matrix provides compression/limiting with gate, EQ and vocal enhancement, reverb and delay. Separate outputs are provided for the guitar and the vocal/harmony/effects output.