Hopefully, this will become a synthesizer written in Rust. At the moment, it's experimental bits of technology toward that end.
At the moment, the main repo contains a very primitive command line app for a simple mono subtractive synth. A MIDI keyboard is required, and the mapping for controls is set up only for an Akai MPK mini. In addition, settings for MIDI and sound are somewhat hardwired; it works on my Windows and Mac systems, but is likely fragile.
There is also a web demo in the synthesizer-io-wasm directory. All it does is play a sawtooth, but it shows that it's possible to compile to wasm and run the synth engine in a browser.