Ever since I got those old JBL 4320 Studio Monitors in Philly for $300 for my birthday last year, I’d added parts and collected bits and done a series of upgrades from the original 2 way design with horns, to a pair of DIY JBL 3-way studio monitors, and finally into DIY 4-way monitors. I’d found a schematic for a model 4333 (passive) crossover network, built that, and had gotten a nice improvement from all that.
I even got an electronic crossover, dual amps and biAmped them.
But, it was still a kind of hack.