Tracks like a zombie, but kicks like a mule - my first taste of yellow.
As Metasonix own video makes hilariously clear, you're never going to play Switched on Bach with the R54. Feed the Supermodule with the appropriate combination of CVs, however, and you can coax deep drums, watery plops, rubber basslines and tortured-animal sounds from this unruly, tube-based VCF/ VCO.
Metasonix R54 Supermodule by navs
Taming the R54 is complicated by some crafty normalization - both the audio and CV inputs also function as outputs. Silent Way failed to map a suitable set of voltages, but this is hardly surprising given the amount of slew of the vactrol-based inputs. I've found plugging every socket helps, typically a short trigger to the audio input and an offset, 'pitch' CV and short envelope to the rest.
The R54 is a wonderfully idiosyncratic oscillator and makes a great, if contrary, companion to the green in my system. While other VCOs might be a better choice for melodic lines, for low-end wobbles and percussive patterns the R54 is hard to beat.