Tricky CA21REX question

[Daze]

I am really interested in finding out how the Impulse horns (see link) are designed. They do look to me like BVR (or short Horns).

The reviews for these speakers (H1, H2,etc...) are simply over the top. I would like to see how their bass alignment could be cloned using the Seas CA21REX (which they claim is a drop-in replacement).

Anyone with experience (from the BVR, Replikon family) has a clue, specifically for the reduced size H2?

Any hint, wild guess, scientific evidence would be welcomed.

Thanks.

http://www.acoustica.org.uk/impulse/impulse.html