BOSS INTRODUCED THE the OC-2 Octave pedal in 1982, allowing guitarists and bassists to add tones one and two octaves below the original note played. With volume controls for each of the three resulting signals, the OC-2 made it possible to mix the pitches as players desire, and with its clear tones and reliable pitch following, it became an enduring classic.
Boss continued to build upon the original with the OC-3 Super Octave, adding a Poly mode that allowed octave effects on full chords. In that mode, the -2 octave knob becomes a control to limit the suboctave range, letting you place it, for example, on just the root note for bass guitar–style accompaniment. The OC-3 also introduced a Drive mode that adds distortion to the octave effect for fatter, aggressive tones.