I recently acquired a pair of the coaxial drivers used in the UREI 811C monitor: JBL E-145 + 2425.

The previous owner built a robust pair of cabinets for them using 1.5 inch thick panels all round which reproduce the volume and tuning of the originals.

However, he contented himself with using a pair of Altec N-604-8A passive crossovers, designed for the 604-8K. The speakers certainly function with this crossover, but it's hardly the optimal solution.

One option for me is to reproduce the crossover design published by JBL in the 811C "Technical Manual."

But I'm also wondering if any users have instead used a modern electronic or digital crossover and, if so, what slopes and crossover frequencies they used, and how they implemented the time alignment feature of the original crossover.

Appreciate any tips or comments!

Thanks! Joel.