The Cwejman RES-4 is a truly great sounding module. It is made of four resonant bandpass filters. The top knob controls the frequency, the middle the amount of resonance, and the bottom the level for that filter. We are running the Plan B Elf LFO, triggering the Model 10 Polyphonic Envelope. The envelope is running into the audio in of the RES-4. We're just using one band to start but then we add another for some added attack. We're also using the super awesome Cwejman VC-FC compressor module, that is now available in stereo as the VC-FCS!