MXR® BASS OCTAVE DELUXE M288 The Bass Octave Deluxe offers two independent analog sub-octave voices with a Dry control and a Mid+ switch to optimize the sound of your parallel clean signal. This pedal can be powered by a 9-volt battery, a Dunlop ECB003 9-volt adapter, or the DC Brick™, Iso-Brick™, and Mini Iso-Brick™ power supplies (not included).