 There is also white noise that can be used as a sound source, it is sent through the filter and cannot be routed any other way.While the Evolver is monophonic, multiple Evolvers can be linked together via MIDI to create a "chain" that, in turn, creates polyphony based on how many units are chained together.The same is true for the Poly Evolvers, up to 5 Poly Evolvers can be chained to obtain a 20-note polyphony.