Why not horns?

Herman, well said, no arguments from me.

Herman thanks for the reply;something I never considered.

Herman,

That's a good point regarding time alignment.

Phase coherency is a must for good sound in my mind, yet this is the first I heard of it addressed in a horn design, yet horns would seem to be the most susceptible.

It would almost seem like a serious defect to not address it somehow when building horns to compete with other inherently more phase coherent designs?

Digital technology saves the day once again!

Phase can be adjusted to a fair degree in the crossover as well.

Mapman, the horns I listen to, as far as the soundstage is concerned, seem entirely recording-dependent as far was whether they are upfront or laid back. IOW they are neutral in this department. Some recordings will have sounds that seem inside the speaker. Others, the speaker seems to not exist as far as the music is concerned.

Time aligned and in-phase are different issues. All of the drivers in a speaker could be mounted with their voice coils in the same vertical plane (time aligned) while one of the drivers is wired out of phase. So time alignment deals with physical relationship.
As explained by someone's post above, time delay can be adjusted to compensate when drivers are not aligned physically. Phase is another matter. It refers to the drivers all operating in unison electrically. This requires that all drivers are wired with the same polarity. As I understand it, a 6 db slope in the crossover causes a 90 degree phase shift. But from there I am lost. Who can explain this for me?