"If the sound source was a perfect radiating sphere of acoustically small dimensions and the throat was conical and acoustically small, I think all wavefront progogation through the horn would be this way. Or if it generated perfect planar waves and the exit was a tube, either way."Compression drivers use of the phase plug is to make wavefronts diverge to approximate a planar wave AFAIK. However, cones and domes make omnidirectional spherical waves.
From this I would think a pure conical horn would be the best way to load a dome or cone driver. Your thoughts?
Randy