Horn modeling software?

[head_unit]

Hello, I'm wondering what software exists out there to model horns. And THEN:
a) Can it accurately model high frequencies?
b) Can it model arbitrary shapes? (Ideally non-symmetrical, imported from a CAD application)

For instance, I read some criticism that Hornresp cannot do #a. And I recall someone told me once that Akabak could model horns, but I don't know if that's true.

And if the answer is NO, what are all these PA companies using to design their horns? (I mean the serious ones, not the ones who just copy the top companies' look)