I'm not specifying anything more (language, etc.), so that I can get as wide of a selection, as possible and so that this post is useful for others more.
Maybe this might be worth a look, too:
It's a recent attempt to make Pure Data more accessible for less technically inclined users.
I'd say from there you can pretty much reach out to the maintainers and go from it.
Another project that would benefit of more help is AudioKit. https://discord.gg/y6fKdWR7
I'd say most modern audio based apps on iOS / macOS are likely using it, although JUCE is the leading framework for audio dev.
The rust community also seems to be booming around DSP.
[0]: https://generativereview.substack.com/p/chatgpt-review-my-co...
Project: Handheld Companion (https://github.com/Valkirie/HandheldCompanion)
It's not ready for random contributions just yet I believe (needs a lot of refactoring, plus the hardware isn't finalized yet) but we're open for suggestions!
Tracktion:
Both very powerful audio frameworks - JUCE does plugins and audio drivers and low-level DSP, oh my - and Tracktion does all the stuff a DAW needs, on top of JUCE.
There are tons of ways to contribute, from building open source samples, to testing, or even adding functionality. Both dev teams are open to good quality PR's being submitted and both frameworks have excellent communities that will get you started: http://forum.juce.com/
These are cross-platform tools which offer Audio developers an extremely powerful toolset. By contributing to either (or both) frameworks you will be massively contributing to the audio world - so many plugins use JUCE these days!
EDIT: see, also, awesome-juce - pick a project from this list to contribute to, according to your interests ..
Creating new Avendish plug-ins (docs: https://celtera.github.io/avendish/) could also be fairly useful, here's a very basic example one: https://github.com/celtera/avendish/blob/main/examples/Advan...
See https://github.com/lancaster-university/codal-microbit-v2 for the ecosystem, or https://github.com/lancaster-university/codal-core/tree/mast... for the relevant section of the API.
If you're interested do feel free to suggest stuff via feature suggetions and such on the issue trackers, and PR's welcome :)
"A platform for audio synthesis and algorithmic composition, used by musicians, artists and researchers working with sound."
https://github.com/sandreas/m4b-tool
Wasn’t quite ready to put this out there, but it might be on topic.
The first release is decidedly simple but maybe you can see where I’m going with this, and happy to talk about future plans and some other stuff under way
https://github.com/burns-fm/pl-10
Excited to see what else pops up in this thread.