|I've been listening for about one week now with the filters set so the hand off from lower-mid to upper-mid happens higher up (upper-mid S2 is high-passed at 4800Hz instead of 3200Hz), meaning the small 400Hz horn is doing only the upper "half" of the mid range. I left the 180Hz horn as it was (790-3200Hz)….
I have not measured the output (too many other things to finish). I don't know exactly where the acoustic transition is happening, or if I am leaving a range uncovered. The point is, that the difference is such that I don't need to measure anything to be sure that this is better than when I had the upper-mid horn high-passed (electronically) lower down, at 3200Hz. I was most likely getting some overlap in the crossover region between the two horns (I don't attenuate the 180Hz "Fundamentals Channel", or any other channels).
So the 180Hz horn is currently handling two octaves (electronically), the 400Hz horn is also now handling only two octaves (electronically)... I like what I hear well enough to not ask these horns to do more than this. If measurement reveals an uncovered zone between the two, I would rather add another horn than to ask more of the existing horns...