If you think the Smith DSH (Distributed Source Horn) exponential expansion diffraction horn "look like a parabolic", you obviously can not tell the difference between those two horn types.
If the DSH exponential sectors were replaced with straight sheets of plywood, then it would be parabolic.
And using "PAR" rather than "EXP" would then be correct for it's simulation.
In that case, you would be wrong!
Bob Smith himself considers it to be an exponential horn in his article published in the January 1951 edition of Audio Engineering:
"Fundamentally the design considerations are the same as those for any exponential horn - i.e, the mouth area must be large enough to prevent reflection at the lowest frequency for which the horn is intended to be used and the rate of taper must be chosen to provide a satisfactory low-frequency cut-off."
For the last time - an acoustic horn is NOT defined by what the "enclosure" may or may not look like, it is defined by how the cross-sectional area of the horn expands with axial length.
Your argument is not even consistent - on one hand you say that a conical horn must look like a physical cone or pyramid, but on the other hand it is okay for a parabolic horn to look nothing like a parabola. In the case of the parabolic horn you are in fact agreeing that it is the linear area expansion rate that defines it.
This is my last post on the matter. If you wish to continue discussing the issue with others, it would be appreciated if you could please do so on another thread.
Some of todays posts have been moved to their own thread. This off-topic has outlived it's invitation.Short term thread restrictions are in place. See how easy it is? It's just as easy to make them permanent if a reason should happen along.
Here is the thread - https://www.diyaudio.com/community/...om-hornresp-when-to-use-a-par-segment.412618/