I actually have already gone pretty deep. A few years ago I got a teensy, molded shells, specced out a nice set of 3 transducers, modeled passive and DSP cross

I actually have already gone pretty deep. A few years ago I got a teensy, molded shells, specced out a nice set of 3 transducers, modeled passive and DSP crossover networks (tradeoffs of low latency IIR mode and high quality FIR mode on the DSP side), and a measurement apparatus. I got to the point in the project where I had to manually solder tiny wires onto tiny surface mount connectors and put the project down. Idk if I'll ever be able to finish it, but it was a fun project. Edit: Oh I forgot to add that I also got tiny microphones and lodged them into the IEM blackplates for ANC or pass-through. It's an ambitious hobby project. I'd be happy to see a proper company do it (or at least incorporate elements of it).