Quick & Dirty 4430-Inspired Two-Ways Part I

[Zilch]

O.K., so what's this tell me about 2431H on PT-F waveguide?

[4313B]

It tells you that you need to get some impedance compensation going on.
That's not too awful though! JBL is getting good with the impedance curves on these transducers!
Post the data file.

Run an impedance curve on just the 2431H so you can see how the waveguide is loading it.