https://www.audioheritage.org/vbulle...re-broken-HELP

The L300 crossover (electrical)
Woofer 12 db LP
Horn 12 db HP, 12 db LP
Slot 18 db HP

Have a look at the Nelson Pass L300 project (Google search). Unfortunately you can’t make a silk purse out of a sour’s ear. But using a systematic approach you can a reasonable way to minimising some of the L300’s problems. You will find some of the problems are less obvious than first thought. The dsp can’t think and determine these issues.

My suggestion is to become proficient with REW using a Laptop and a calibrated microphone so that you can do your own research. Relatively speaking the networks JBL put together back then were crude. Mainly built for power handling and reliability.

Measure the system as a whole on and horizontal off axis (important)
Measure each driver individually with the stock crossover
Measure each driver without the crossover.

Listen for enclosure resonances using a swept sine wave. You might find adding additional fibreglass beneficial in certain locations inside the enclosure.

Listen critically to each driver with different program material with the other drivers turned off using the DSP crossover.

Decide if you are going to use the original diaphragms and the original woofers?

While what you have said is in a general sense correct you will need to make some decisions about the crossover frequencies and the specific characteristics of each. The DSP won’t pull a gene out of a bottle for you.

If it were me….
Pull out the mass ring in the 2235H then measure and EQ in DSP (as above).
Measure the LE 85 on the horn (with a new D8R2425 diaphragm) on and off axis. Find the -6 db point off axis angle between 700-1200 hertz. Do the same measurement with the 2235H.
Crossover where the 2235 and the LE 85 off axis -6 frequencies intersect using a 24 db LR acoustic slope measured with REW.
Measure the acoustic time displacement with REW at the crossover point. Add dsp delay to the woofer
Match the woofer and LE 85 levels then measure the two drivers in phase and out of phase. Reverse phase should produce a uniform null at the crossover point.
Using a REW measure the LE85 break up point (around 8000 hz).
Repeat the above process for the LE85-077 crossover point.

The key is to rely on your own measurements and what you learn as you go along. Then listen critically. The above will get you in the ball park but personal preferences come into play. Oh the 2235H is not a great driver above 300 hertz. It’s dull and muted compared to how it sounds with mass ring out.