hi,
I have built a set with passive crossover that I like the sound of very very much. One of the key features in the crossover is the parallel resistor over the +/- from the 2420 driver. As this is only about 1.2ohm, this damps the impedance peaks of the driver/horn combo a lot. A series resistor of about 6ohm brings the nominal level to about 8ohms again so the amp doesn't see any low impedance. I can do this because I don't need the voltage sensitivity of the driver.
Yesterday I connected my newly acquired 2440/2382 combi to my active m552 crossover and it didn't sound as good as my passive 2420 setup by far. It might have something to do with the fact that I only had about 20uF of capacitors that I could put between the amp and the driver for DC protection. The 20uF makes a 1st order crossover itself in the 500-1500Hz range [about, I don't have my calculator at hand]
Now I have also done the "parallel resistor trick" with the 2440 and I like the sound much better. I think this has to do with the impedance peaks that the 2440/2382 combi shows at about 800Hz, which is right in the crossover range of between 500Hz and 1500Hz that was created by the 20uF capacitors for DC protection that I tried out.
And the 1.2ohm in parallel effectively shorts the driver resonances, like a bad tube amp would do, so it's also damped more.
The sound is much more sophisticated now, with much less "ssssssss" spitting out. And more balanced because the impedance peaks are no longer there because of the 1.2ohm in parallel. So the voltage driven crossover curves created by the active crossover, arrive at the 2440 as they are intended.
greetings, Frank