In the early days of analog synthesis, you had to just turn knobs really slowly and imagine some planetary bodies moving around. Now we have computation. Let’s make ambient space music that’s accurate.

Synthesis of moons, from the maker of GleetchLab

Developer Giorgio Sancristoforo of GleetchLab fame is never short of far-out ideas. This week, he’s up to a software synth called Quadrivium. (A first preview was spotted by the ever-vigilant skywatchers and YouTube cosmonauts of Synthtopia.)

Basically, you can produce a really slow modulation source by modeling accurate orbital projections of Jupiter, Saturn, Neptune, or even pull data right out of Uranus. (hey, no snickering!)

Not only can you use it with Giorgio’s nice drone synth here, but there will be MIDI output, too. (The synth, for its part, has four oscillators, a mixer with distortion, a modulation matrix, a massive filter bank, and of course tape echo.)

12 moons orbiting around the four giant gas planets as modulation sources? Yes! Orbital data from Jan 1 2020 to Jan 1 2030 (hour by hour) are used in the forthcoming Quadrivium synthesizer to modulate oscillators, filters, delay and create incredible spacey soundscapes. Did I mention that you can also use the moons’ orbits to modulate your MIDI gear? 😀

Soon available at

Watching for this one. David Abravanel wrote an in-depth profile of the developer, well worth revisiting while we look forward to Quadrivium:

Vult Caudal and the four-body problem

Giorgio isn’t the only one musing on planets and orbits. The exceptional Vult Caudal module in open modular platform VCV Rack also explores the notion of gravitational math as a source of modulation in music. That resonance between musical form and astronomical patterns traces back from modern music through the Renaissance, the Islamic Golden Age, and classical antiquity (at a bare minimum). But now we have a uniquely precise model informed by better awareness – at least on our local scale.

Here’s the basic idea. You have a basic idea of gravitational attraction between two bodies. (Jump, if you’re unclear.) But zoom out to even the level of the solar system, and you have to account for gravitational impacts between multiple bodies. Calculating that math is important if you want to do something like land a probe on Mars; in math, it’s known as the n-body problem.

Leonardo (great name for this topic, the VULT developer) wrote in depth about why he took this inspiration. He includes code examples that are easily readable even if you’re not a coder and barely remember your high school math and physics:

Caudal 2: the four-body problem

He explains to CDM – including why this will produce very different results in contrast to the more-regular planet-moon orbits in Quadrivium:

In my case, instead of 3 planets, I added 4 planets. Contrary to the 12 moons simulation, the orbits (voltage signals) produced by Caudal tend to be more chaotic due to the lack of a large central planet.

PLANETS is one of three models in Caudal; there’s also a four-pendulum model and a “fish tank” based on fish behavior.

VULT Caudal is available in both a free edition and in a paid suite:

For more on the history of planetary motion, NASA has a good summary:

Planetary Motion: The History of an Idea That Launched the Scientific Revolution

Ready to go to Mars?

As it happens, I got to sit in the audience for an extended talk on this topic from Sven, a mission planner at the operations program of the DLR, Germany’s space program. Sven spoke to the legendary German CCC conference about what all of this means if you are actually trying to plan a spacecraft trajectory:

This isn’t just nerding out, though – there’s something extraordinary happening. We have now some synergy between people using the more complex version of this math to actually fly spacecraft, and musicians using simplified equations and code to make interesting sounds. Coding something like this to me is far easier to grasp than the endless pencil-and-paper work I did as I struggled to learn math.

And there’s an opportunity for musicians to help teach physics and engineering topics in a way that can be seen and heard, not just described int he abstract. (Plus the musical version is a nice simple way to wade into the topic, clear of the messy real-world spacecraft-flying equations.)

I’ll revisit this topic in coming weeks, and certainly welcome input. But consider this – we have many people with music training out of work. We have many young people around the world seeing their education disrupted by the pandemic. As a species, we are faced with increasingly complex and specialized scientific knowledge that we need to navigate for our very survival – but often no way to access that knowledge in accessible ways.

I don’t have to convince most of this audience. Show of hands – who has ever thought, “oh, I wouldn’t have struggled with math/calculus/physics if someone had just showed me coding and music synthesis”?

It’s not that we need this knowledge to leave Earth. It’s that we could use space to better understand science, math, and engineering to make Earth survivable.

And why shouldn’t that also sound like really cool music?