I wonder if there's more performant wasm implementations that can interface with the WebAudio API [2]? Quick search brings up things like [3]
[1] https://en.wikipedia.org/wiki/Frequency_modulation_synthesis
[2] https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_A...
[3] https://github.com/a-cordier/wasm-audio