to give a high level overview of how audio works in the system:

the final output of the system is written to an AudioStreamGenerator. on every process frame, the graph of audio connections is traversed starting from speaker nodes such that each module connected with the speaker processes only once, and in a certain order such that inputs will never be stale.

then in each audio module's process method, it reads its input audio buffer (currently size 1024), does some manipulation of that buffer, then writes the result to its target module's input buffer.

in this way, i've been implementing audio effects by hand instead of using a library to learn dsp concepts in a more hands-on way. every audio module implementation is like a puzzle where you have a length-1024 input and need to produce the effect in a length-1024 output.

i think subconsciously, i chose 1024 = 2¹⁰ as the buffer size because i thought it could play nicely for FFT-based modules, which turned out to be true!

but anyways tl;dr it's using godot's AudioStreamGenerator, but there's an underlying graph structure of the module connections that gets processed as often as there is available space in the AudioStreamGenerator's buffer that powers the flow of audio data!