Closely following a know JBL design is a sure fire way of getting a good result. Spinning your own design isn’t necessary a simple and straightforward process. This applies to dsp crossover networks where there is a limited knowledge of the drivers/horn and woofers and a very limited understanding of dsp crossovers. I have seen people spend a large sum on JBL S98000 components only to see it all on the market 12 months later out of sheer frustration. It takes real skill and experience with designing a loudspeaker from scratch and even then sometimes it just doesn’t come together.
In an interview Greg Timbers offered some very good practical advice.
Put together a rough out of your loudspeaker enclosure. Using a passive crossover test board with some switchable text book crossover options simply try the horn/driver and listen to it before considering any measurements. This might include a simple passive CD EQ compensation.
If you can’t get a promising result at that point it might not get much better!!
So try a different woofer, driver or horn.
(This assumes your drivers are in good working order)
If anyone is interested l will post a schematic of a switchable passive crossover.