I created the original Learning Modular Synthesis course for those who were complete beginners to the world of modular synthesis. The next question became: How do I help users reach the next level? The answer is the Eurorack Expansion Project. The idea is you have a nice core system, and want to know how to intelligently expand it – particularly if you interested in a specific technique or are after a certain sound. I’m tackling this in two parts: an online course, and a weekly series – including a dedicated Patreon page for the hard-core users out there.
The AJH Synth Ring SM is three modules in one: a ring modulator based on an analog transistor core design, a sub bass generator that creates tones 1 and 2 octaves down, and a 5 input mixer based on the classic Moog CP-3 design. This mixer is used to combine the original inputs, ring modular, and sub bass sounds; you can override them by patching in alternate inputs. The bonus preview movie from the soon-to-be-released Eurorack Expansion course focuses on the ring modulator section, showing a few different applications as well as really focusing on the waveforms and harmonic spectra it creates so that you better understand how a ring modulator works:
The Sputnik Modular West Coast Random Source is a very capable Eurorack-format update on the classic Buchla Source of Uncertainty module. In this movie, I focus first on uses for those 1:2 switches, including using them to send alternating note-on gate or triggers to alternating drum sounds. Then I move on to showing the sample and hold itself, first with the typical “science fiction soundtrack” random pitch technique, and then for something more subtle such as randomly changing the pulse width.
A favorite “West Coast” module that synthesists of all tastes should check out is the LPG: the low-pass gate, which acts like a VCA but with a filter element that also dampens the high frequencies. A new “hybrid” application I’ve found LPGs to be useful for is to process the output of dedicated percussion modules. An LPG naturally damps both the amplitude and harmonics of the input to mold most sounds into a typical percussive shape, freeing you up to dial in the initial noise and harmonic mix you like without worrying about the original sound ringing out too long or taking up too much room frequency-wise in a mix.
You hear many users search for an “extreme” filter to add to their system, looking for one that is unstable when pushed, screams when provoked, and otherwise makes their instrument more aggressive, less predictable, and in general fun to play with (if you’re the type of person who likes to play with knives). Filters based on the Vladimir Kuzmin’s design in the Russian Polivoks synthesizer fit this description. My favorite variation of the classic Polivoks design in the Erica Dtech VCF, which extends the original design. In this video, I explore how to push the Dtech filter into unstable, aggressive territory
This module – a recreation of the classic Serge Wave Multipliers (VCM) module from the early 80s, adapted partially to the Eurorack format – contains a nicely-rounded, tube-like clipping or saturation; a wave folder that emphasized the odd-numbered harmonics; and a three-stage full wave rectifier that emphasizes the even harmonics. The video in this article focuses on the wave shaping section, and compares its analog sound to the digital one included in the Expert Sleepers Disting; I also discuss matching Eurorack levels to work with Serge-inspired modules.
