{"id":1350,"date":"2026-05-07T09:43:24","date_gmt":"2026-05-07T08:43:24","guid":{"rendered":"https:\/\/mohoyt.com\/blog\/?p=1350"},"modified":"2026-05-07T09:43:26","modified_gmt":"2026-05-07T08:43:26","slug":"siren-a-workshop-system-drone-oscillator","status":"publish","type":"post","link":"https:\/\/mohoyt.com\/blog\/2026\/siren-a-workshop-system-drone-oscillator\/","title":{"rendered":"Siren – a Workshop System Drone Oscillator"},"content":{"rendered":"\n

I’ve been spending time recently with my Music Thing Modular Workshop System<\/a>: a complete modular synth in a small peli-style case. It\u2019s mostly analogue, but it has a digital computer module on the left that\u2019s powered by cards. For each card the hardware stays the same (a few knobs, a switch, two audio in jacks, two CV in jacks, two pulse in jacks (and the same for audio\/cv\/pulse out)) and the card you plug in decides what the thing actually does. Reverb today, Turing machine tomorrow, something I wrote myself the day after.<\/p>\n\n\n\n

Siren is one of those something-I-wrote-myself cards. It’s a multi-algorithm drone oscillator, and the code is on GitHub<\/a>.<\/p>\n\n\n\n

Why?<\/h2>\n\n\n\n

A few reasons, really.<\/p>\n\n\n\n

The Forge TME Vhikk X<\/a> had been on my radar for ages – its SEED\/SCAN paradigm (structural randomisation on one knob, timbral morphing on another) is a really nice way to think about a drone, because it separates “what is this thing fundamentally made of” from “what does it sound like right now.” I think that split is the bit that makes it interesting to play with rather than just set and forget.<\/p>\n\n\n\n

But Vhikk X is a popular module, and as a result a hard one to get and also on the expensive side. I also didn’t really want another module taking up rack space when I wasn’t sure that I needed it. So the obvious thing was to write the card I wanted and use it as a trial to see if this was a module that I should get.<\/p>\n\n\n\n

The other reason is that I’d been wanting an excuse to get into the Workshop Computer development side of things. There’s a vibrant little community<\/a> building cards in C++, Rust, Python, Lua \u2014 and the ComputerCard.h<\/code> header gives you a really clean abstraction over the hardware. I dipped my toe earlier by adding some arpeggiator features to the chord blimey card, But now I wanted to do something myself.<\/p>\n\n\n\n

What it does<\/h2>\n\n\n\n

This is where I took lots and lots of inspiration from Vhikk X and its documentation. Six oscillator banks, each with its own character:<\/p>\n\n\n\n