You could also look at analog active crossovers. There are many to choose from including DIY kits designed by Nelson Pass.
In recent years I've used an ART CX310 and CX311 on two systems and I'm quite pleased with the results.
They are fairly easy to setup and adjustments can be made in real time, as you listen.
Measurement tools like REW are certainly helpful, but not required.
Sorry, I don't have experience with DSP (yet) for comparison, but I am interested in how it works out for you.
For me, going active made a very noticeable increase in clarity and detail across the entire audio spectrum. With quality recordings, it's simply startling how real it can sound. Best of success!
