Use liberally for mind-crushingly thick bass tone.
The Ashdown Sub-Octave Plus Bass FX Pedal generates a note one octave below the note you play that replicates the original waveform with the same volume level. You can blend the sub-octave note with the original and add adjustable distortion to the sub-octave to give your playing even more heft. Housed in a durable metal case, it has the famous Ashdown VU input meter and controls for Input, Sub Level, Sub Tone, Distortion, and Output. It can handle passive and active bass signals, plus it has true bypass circuitry. 9V battery or DC adapter power.