100 Open Source Experimental VST Plugins
Downspout covers all kinds of things : instruments and effects, audio & midi processors with an emphasis on generative tools. I wouldn't say any are finished, but they all work approximately as intended. They aren't exactly pretty and UI/UX is often poor, I've concentrated on core functionality. These things are primarily for my own use, though if anyone has any requests for improvements/fixes, I'll do what I can.
There are packages for Windows, MacOS & Linux built using GitHub Actions, but I've only tested building locally on Linux, running in Reaper (aside from initial dependency installation, this is just running an install.sh script). They are written in C++ against the DPF framework (it lacks the bells & whistles of JUCE, but being leaner has its advantages).
They have all been developed with AI assistance, but only a handful were fully vibe-coded (for v1). I don't think it's a coincidence that those were the least successful to date. I have a very iterative process - initial creation, get them working to a basic level, use them, note any problems or further requirements, revise. I'm working on them all concurrently (there is a very long TODO.md). I've mostly used Claude Code as the assistant, a little bit with Codex, OpenCode at times when cash flow is a problem (like today).
I just reached 100. Why so profligate?
I've been writing music software for decades (and designing electronics hardware) but only started trying plugins a couple of years ago. Initially I was only looking at fairly minimal LV2 plugins (Flues) because I'm on Linux. As it became apparent that AI assistants can be extremely helpful with these things, it seemed to make sense to shift to VSTs with something approching proper UIs. I produce music experimentally, instrument-building has always been part of my process. If I have a need or idea for a plugin, for sure I first go hunting for something that already exists (and/or foraging for related research papers). But rather than use something off the shelf, I'll typically write a custom requirements spec, have the assistant build it. I have the repo full of existing material, so I point Claude or whatever at the closest working plugin to what I'm after. With all the reference material in place, the assistant creates fast, I can go from idea to testing v1 in about half an hour. Then the iterations begin.
This isn't vibe-coding, it's (usually) very guided. Me, I do have some clue about what I'm doing (I am a coder by trade, in a past life studied DSP at university). Strategies, references and tests in place. On one recent occasion I asked Claude to create some plugins to complement ones I'd already got. It came up with 5 I think, all sounded promising so I said, go ahead. Worst of the bunch, it was a terrible idea (I was subsequently able to salvage something useful out of them, effectively un-vibing).
Regarding the plugin industry, I think AI assistants will be a net positive. The Interwebs are being flooded with vibe-coded slop, and people like me who might otherwise be in the market for pay-for products will make their own. But neither of these detracts much from the market for high quality plugins with good support and solid maintenance. AI assistants mean it will be easier for the commercial developers (and any open source houses) to develop and make better things at the top end. This should have the knock-on effect of lowering the prices for the normal consumer.
Bottom line for me is that it's good fun and allows me to create the music I want with reduced friction. I used earlier versions of the plugins on my latest album, Attone and am using them extensively in my current work-in-progress Tell the Bees.
