I don't understand the different modes. Please explain.

There are many ways to incorporate your VR into your setup. Scalic mode is for determining specific key signatures and choosing between 4 major or 4 different minor set scales for the harmonies to be based on. This way it is almost automatic, yet appropriate for that key and scale. This is most effective when singing melodic lines and desiring the harmonies to follow more directly to the melody. Notes mode is useful for having the VR choose exactly the harmonies you tell it to in real time by sending the appropriate MIDI note information. For example, when you play a MIDI note, the harmony will be pitched to that exact note. Chordal mode is useful for padded background vocal harmonies, such as ones used in the chorus section of a song, or when thick backup style harmonies are needed to only be set to specific intervals, or chords, in that key signature. These chords can be a preset or determined by MIDI note information sent to the Vocalist.