Music and Modular are uneasy bedfellows. Modular synthesizers often modulate between traditional musical forms and doing their own thing. While it can speak the language of music, it can find itself resonating in strange dialects. At times, it can be painfully classical—mimicking orchestral tropes and emulating instruments. At others, it can agonize its way through the freest flowing movements of atonal mysticism on a journey it hasn't yet thought of. Over time, it ebbs and flows from musical intent to experimental adventures depending on who is at the reigns.
In recent times, the modular flow has leaned towards the traditionally "musical." It's driven, I imagine, by musicians tempted away from the safety of free intonation into the idea of the compositional expressiveness of modular, but who can't quite shake the need for musical order.
The ultimate disruption to the free movement of voltages comes in the shape of the piano keyboard. We saw this with the work of Dr. Robert Moog—who, at the advice of some key collaborators, wrangled the Moog Modular system into some kind of sensible, playable product by adding a keyboard. And before you knew it, polyphonic ideas were demanded from a stubbornly monophonic eco-system.
I find it interesting how there are multiple electronic streams within ostensibly classical "art" music where, on the one hand, you have traditional musical forms being realized in electronic form—as with Wendy Carlos's Switched-On Bach, and on the other, artists like Morton Subotnick exploring “new kinds of music” through modular machines. Despite the passage of over fifty years since their most seminal works, all of these streams still exist within the artistic endeavor of musical expression.
Musical Strategies in Eurorack: Quantizers + MIDI to CV
Returning to the present, the sheer weight of musicians dabbling in the delights of Eurorack and modular has opened up a market for musically exciting modules. Eurorack can be approached from the standpoint of engineering, where voltages are manipulated, signals are combined, and the outcomes are both scientifically and aurally interesting. Pitch can uncertain and largely unimportant when compared to experiments in probability, logic and voltage processing. However, while fascinating to many, that approach won't easily satisfy musicians interested in intervals, octaves, chords, etc.
Thankfully, there is still a lot of resistance to the dominance of the keyboard, even for musically-minded people. I believe there's an understanding that while keyboards can be incredibly useful, they can also misrepresent a modular system and render it into becoming just like any other synthesizer—and after all, that's not what many of us are after. Instead, we start to tame the voltages in ways that appeal to both the musician and the engineer. So, how do we approach the creation of melody and harmony without the keyboard?
Quantization is usually the first port of call. It can take the infinite resolution of moving and sequencing voltage and "snap" it into the defined steps of notes, intervals and octaves. You select the notes or scales, and the voltages will obey, allowing you to turn your dissonant VCOs into obedient purveyors of equal temperament.
With a single voice tamed, then inevitably more voices will need to be lashed to the same restrictions. Two, three or four monophonic voices, patched individually through your rack, will find themselves singing from the same hymn sheet. Some quantizers offer multiple channels of voltage conditioning to bring several voices into line with one another. The QQ2 Quad Quantizer from Tenderfoot Electronics is a good example. It has four channels for your sequences that are then guided through the same confining scale. The ADDAC207 Intuitive Quantizer takes this further by providing individual scales for each of the four channels while allowing for global shifting and transposing.
A system with a splash of quantizers and interwoven transposing voltages can find itself enjoying harmonies, unisons, chords and intervals without necessarily pushing them with the intentionality of making shapes with your fingers on a keyboard.
If the keyboard is the only musical language you require, then the presence of a MIDI-to-CV module can bridge the connections between your playing and the modular outcomes. The Mutant Brain from Hexinverter, for example, will take each note you play and allocate it to one of four CV outputs, which then infect your modular with musically correct voltages of up to four notes of polyphony. But there are plenty of modules that offer ways to enjoy musical harmonies without having to resort to a keyboard.
Musical Strategies in Eurorack: Harmony-Oriented Sound Sources
A good place to start is the Chord V2 from Qu-Bit Electronix. It has everything you need to drown your modular in polyphonic voices. It features four wavetable oscillators with eight banks of morphable waveforms. These are addressable from a single 1V/oct input, which controls the root note around which everything else swirls. Within Chord V2 you define the voicing and quality of the notes that form your chord. Each chord contains a root, third, fifth and seventh. You can push these apart, invert them and set the quality relationships between them. So, with a combination of transposing the root note, and modulating the voicing and quality, you can generate a movement or progression of synthesized chords.
If you want to treat the oscillators individually, you can do that via the independent outputs. There's a mode where you can sequence each in isolation or run them in unison for huge, stacked sounds.
In a similar vein, we have the Poly Cinematic and Pianophonic from Knobula. Both modules are sound sources that can be played via MIDI, but, and I think more interestingly, they have internal functions that help us explore harmony in a modular context. The Poly Cinematic is an 8-voice virtual analog synthesizer. It's packed with multiple oscillators per voice running supersaws, detuned pulses and a tonewheel organ. The Pianophonic is an 8-voice wavetable synthesizer that ships with a whole range of piano sounds. What they share is an ability to play with harmony through a single 1V/oct input.
The Detune knob offers a way to push the oscillators apart. It starts with unison and all the oscillators stacked up upon one another. As you turn, you go past the wobbling of slightly offsetting the pitch into semitones, and then tones until you reach a 5th at the centre position. Turning further pushes it all out to octaves and sub-octaves. It's a simple way of bringing two and three-voice harmony into your modular using a single voltage input. However, there's another slightly hidden feature that's only betrayed by the "Chord Select" CV input. These modules have an ability to store user-defined chords which will then play whenever you send it a gate. To create the chord, you have to connect a MIDI keyboard and actually play them. The MIDI data is then stored in up to eight voltage-defined slots. The only way to select a chord is via the "Chord Select" CV input. So, you’ll have to patch in a source of voltage like an LFO or a sequence to select the slots and create a chord progression. It would be lovely if these modules had a knob to select the chord—however, modular limitations can often be precisely what we need to push us further into experimentation and understanding our interconnected systems.
The Ensemble Oscillator from 4MS takes the voice count up to 16. It combines additive, FM, phase distortion, and wavefolding into what may fairly be called a bit of a monster (in a good way!). The oscillators are essentially sine waves, which are then manipulated through folding and modulation to produce complex outcomes. The 16 oscillators can be spread apart over a range of notes defined by the selected Scale. Underpinning the harmonies is a quantized Root note that can be sequenced independently of the non-quantized pitch oscillators. If you use it as sine waves without any folding or modulation shenanigans, it sounds very much like an electric organ where you pull out various stops and registers.
You can do some interesting things with the root and oscillators with panning. In some modes, the root gets panned opposite to the rest of the oscillators. In another mode, alternate oscillators get panned left and right. The relationship between the root and pitch is that the pitch controls the pitch of the entire ensemble, whereas the root is the lowest oscillator, which can be moved around independently in reference to the pitch. This means you can do clever things like manipulate the bassline while holding the same chord. Both Spread and Scale can be modulated so you can vary the density of oscillators and their relationship while transposing.
Another elegant and beautiful harmonic canvas comes in the form of the Instruo Saïch. It's encouragingly simple and features four sawtooth oscillators, a built-in VCA, and some controls over intervals, detuning, transposition, and offset. What makes it straightforward is that you have four 1V/oct inputs—so you can address each voice independently. The oscillators share the main pitch control, so they will always be related to each other. Put in four complementary sequences, and Saïch will sing and harmonize to your command.
However, Saïch is also cleverer than that as well, and will happily let you explore harmony from a single v/oct input. The horizontal fader at the bottom of the module has a few different functions, but the most harmonically intriguing is the mode for Intervallic Offsets. As you move the fader from left to right, a root note is retained while the other oscillators move from unison to octaves, a fifth above and a fourth below. You could think of it like "interval scanning," and when modulated, it can generate a pulsing flow of expanding and contracting voices.
The Saïch pairs beautifully with the Instruo Harmonaig—a four-voice quantizer that's designed to generate harmonic possibilities intuitively. You can control the voicing, inversion, transposition, and scale all from the one module. Although it claims that you don't need to have a deep knowledge of music to operate it, I think it's at its most useful in the hands of a seasoned musician.
Control vs. Collaboration
The sort of modular functionality on offer here can appear complex and restrictive when compared to the ease of a keyboard. Why spend all this time trying to evoke chords or modulate intervals and tune oscillators? Surely you could just play them, right?
However, once you start modulating and experimenting with the voltages, sequences, and random values that pour effortlessly from a Eurorack system, you'll discover that it's simply another way of generating music. Injecting voltage control into voicing and oscillator spreads will produce outcomes that you perhaps never intended or thought of. The beauty of quantization in modular is that it places just enough restriction on pitch and relative pitch to keep things thoroughly musical while refusing to be tied into a single melody.
The result can be breathtakingly original and alarmingly experimental. So, at least attempt to resist the keyboard; take your music theory and apply it to oscillators, tunings, and modulations, and you'll find that the modular machine becomes a collaborator rather than simply an instrument.