What is the best CD horn with a 1.5" throat?

[Carl_Huff]

Have you taken a look at the 18 inch SEOS Waveguide in fiberglass?

 

[ReinoutdV]

Have you ever considered the Beyma TD385 ?
Constant directivity.
Officially from 800 Hz upwards but when you see the polar plots this works also on lower frequencies.
https://www.beyma.com/speakers/Fichas_Tecnicas/beyma-speakers-data-sheet-horn-TD385.pdf

I got a pair here that came with the compression drivers i needed.
Serious made stuff; this is no flimsy plastic !

Regards, Reinout

 

[ReinoutdV]

Sorry,
forgot the add some pictures of those Beyma TD385's.

Regards,
Reinout

 

[ErnieM]

Acoustic Horn Design – The Easy Way (Ath4)

A couple real world measurements on this page.

No finalized designs yet. The Seos 18 might be your best bet until the then.