The Subdecay Prometheus is a voltage controlled 12dB filter which can be manipulated by playing dynamics or an internally generated signal.
But what does it do? Just about everything you've ever wanted in a filter pedal. Loads of headroom, reasonable size (measures about 3.7x4.7 inches), Highpass, Bandpass, and Lowpass filtering with adjustable intensity (resonance), forward and reverse envelope following, Sample/Hold step filtering based on 3 different wave forms, and it can operate with a single 9 volt battery or standard 9 volt adapter.
All that and it has some "hidden features" as well.
- The LFO rate can be adjusted to run much faster than the the step rate. This can be used to create very interesting arpeggiation.
- The Depth knob can push the filter cutoff frequency outside of the audio range. This can be useful to create a slow attack effect.
- The step rate can be turned up high enough for smooth modulation. This can be used to create and autofilter effect, that can sound similar to a phaser or tremolo.
- A fixed filter effect is possible by turning the depth knob down all the way, and using the Frequency knob to set the filter cutoff.