Not the same JBL's but I run 4722 Cinema speakers using a digital active crossover. What are you using as a music source? Is there a computer involved? If so, you may be interested in going digital XO. A bit of a primer here: http://www.acourate.com/XOWhitePaper.pdf A much more detailed response is in my sig.

Another member here, pos, has developed software that can also generate digital XO's: https://sourceforge.net/projects/rephase/