As the first post by Ian says, it is indeed a horn. A shallow one at that. I don't know the technical name for that geometry.

A horn is a type of waveguide. I suppose this may be the case of a horny waveguide.

https://www.axiomaudio.com/boards/ubbthreads.php/topics/400862/1/New_Tweeter

Last edited by Mojo; 08/05/21 06:39 PM.
House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated