If the same driver is mounted on a round tractrix salad bowl horn, what happens to the axial sense? I am thinking in consideration that the given amount of acoustic output power is being spread out more with the round horn, yes? Or is this "apples to oranges", given that the round horn might have different loading/gain specs. (D.I.,etc.).

About how large a mouth diameter is required to use an 800Hz. XOVER freq., and how long is the typical throat to mouth length?
Just thinking generally, no specifics really needed yet. I'm trying to visualize the physical size a round horn actually requires.
Thanks, Sam