You wont get anyone Designing and CADing a horn bin for free
it takes alot of work.

so either-find some one who will for $
or
work it out yourself
or
find an existing flare for it.(not likely)

i can use hornresp,CAD basshorns etc.but thats about it!

what is the exact freq range u want? 250-2k?
usable freq range is up to 3.5k it says.so that isnt a bad factor!

notice that the freq response chart shows a rising response above 1k or so,
also remember hornresp doesnt take into acount actual response up high(theres lots of posts on this in high eff forum too)

Wayne can surely comment on the directivity and such like to match the HF etc.

Cheers

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