The electronic components for passive crossover are pretty simple, being capacitors, inductors, and resistors. There are both component and design issues that define how well any of this works. More complex better designs cost more money to produce.
All very cool stuff if you have an interest in electronics.
Indeed, this is all cool stuff. I'm always amazed at what can be done by controlling the "simple" electron and also the "humble" bit (in software).
Although this is not my domain, I've worked with many circuit designers over the years. This field is so large that there are several sub-domains where techs and engineers specialize in analog, digital, microcircuits, power supplies, etc.