Using the spice tools and circuit models you provide; and other number crunching and plotting tools:

No matter how I analyze and model the system I seem to predict a 3 or so octave wide notch in the response centered at about 2000Hz. Am I correct? The notch is apparently crossover generated, and I can't find any component of the system which compensates, or for which it compensates.

I imagine this is probably a more complex issue than I am assuming - what with phase cancellations and so forth. But it bothers me :) and inquiring minds want to know.

Thanks.