I just finished up installing the mode switches this evening so I'm now all done building my new segmented ESL's.
I have them playing in narrow dispersion mode at the moment and I've not yet decided which mode I prefer, as each has advantages.
The narrow mode gives spooky real imaging and amazing slam but can be a bit intense and piercing on loud passages. And of course, the tightly focused sweet spot isn't much good for entertaining guests.
Wide mode spreads out and totally eliminates the "head in a vice" effect and isn't as in your face, yet still retains quite good imaging without giving up much slam (can crank out 105 db at 3 meters).
Switching between wide/narrow dispersion modes takes about 90 seconds to crank volume to zero (too much voltage to switch under load), turn selector switches on each speaker, recall the saved EQ curve on the Behringer, and then crank the volume back up.
I'm officially calling this project a success !
El-Cheapo Soviet military rotary switch for selecting modes:
ESL, filter network, and mode selector switch box:
All finished!