I spent the weekend seeing whether the Fluance drivers lent themselves to an all-out redesign of the crossover network. As it turns out, the drivers are beautifully behaved over a usable portion of their frequency response. It did take quite a few components (18, including 4 inexpensive resistors and one high-quality capacitor that could be harvested from the existing board), but the result was a very smooth response with excellent phase integration and a benign impedance curve that varies smoothly between 4 and 8 ohms. I've attached the on-axis plot. The off-axis response is also very smooth on out to 45 degrees. The design is optimized for a listening distance of 10 - 12 feet. At that distance, the simulations show that the slightly elevated portion between 300 Hz and 1200 Hz flattens out. I've also attached that simulation. As I explained in my previous post, you can ignore the portion below 200 Hz both plots, where room effects come into play. If you compare the plots with the previous ones, you can see that the average sensitivity hasn't changed. These measurements weren't scaled for the standard sensitivity spec, but I would estimate that it's around 88 dB, which is excellent. I think the sound is first class, with excellent bass power handling. The woofers don't go much below 40 Hz, which is the trade-off for high sensitivity, but it's certainly good enough to rock out and alienate the neighbors.
All of this is a little academic, since not many people would want to undertake the mod. I'll try and trace through the stock circuit today (always a pain with printed circuit boards) and see whether there's a simpler approach that might be implemented in the field.
