An article describing crossover networks similar to those shown below having slopes on the order of 120 dB / octave in a Belle Klipsch can be viewed here. The article explains their benefits which are improved stereo imaging and a widening of the "sweet-spot". The article also investigates such factors as filter ringing, group delay, driver interaction and time alignment. The artice is hosted by Klipschcorner.com
Low frequency * Woofer / squawker networks
High frequency * Squawker / tweeter networks
Take a peak at some installations of the extreme-slope networks
The networks in a Belle Klipsch with an Altec 811b squawker horn+JBL driver and a Beyma CP25 tweeter. These are early versions of the ES700 and the ES7500T.
This a newer installation in the same speaker. It uses the ES500T and ES5800 with Trachorn 400 and the same drivers.
The network in a stock Klipschorn.
In Klipschorn with K55+Altec 511b squawker horn and a Beyma CP25 tweeter.