How to curve a horn

Hi, I am looking some information on how to “curve” the construction of a horn. I can model a straight exponential horn in horesp, but how can I curve it?

15study.jpg


In this image, each section is 3” apart. But as the horn starts to curve does the 3” measurement get blended around the curve or is it a straight point to point line.

I am thinking that it would be best to find the centreline of the horn, and measure the 3” as a curved “arc length” as opposed to a straight point-to-point measurement. Is this correct?
 
AFAIK, those 3" sections follow the center line. I did a Hornresp simulation in another thread, the WE 15A is an exponential horn.

As for the lengths of the walls/side, that's a difficult one. Perhaps someone here knows.
 
A we15a is actually what I am building. I have seen your other thread and I have the measurements for the center line. I am trying to figure out how to measure the distance between each 3” segment of the center line. Whether it should be be straight 3” or 3” bent around the curve of the center line (which would make it less then 3” point-to-point)