a HORN actually amplifies the output of an emitter by providing an acoustic matching between the emitter and the air. It of course makes the output sound MORE directional than what it already was. Are you agreed? If So, here's the main question:
Why a Tweeter uses a HORN so that make the output of the horn more directional than what it already is? I think the high directivity of a tweeter is not good, so why do we need to use a horn to makes the directivity situation more critical?