The Voice Box creates harmonies that are determined by he notes you sing and the chords you play on your instrument. The device also has a vocoder function, an octave mode, a whistle effect (synthesizes a whistle tone two octave above the notes you sing), and a unison effect (allows you to do a formant shaping effect without pitch shifting). The Voice Box offers three dual harmony modes (Low, High, Low + High) and three different dual-harmony modes. You can also save up to nine presets and scroll though them using the Mode knob or the Preset footswitch (not included). The unit has a built-in mic preamp with gain adjustment and switchable phantom power (1/4" and XLR input jacks are provided). There's also a 1/4" Instrument out and a balanced XLR Effect out or interfacing with mixers and stage breakout boxes.