Why not horns?

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?

Anybody know offhand if/how Klipschorns deal with time alignment?

Macro, you are a bit off base on that one. It is one of the common misconceptions in audio. Your description of being physically aligned is correct but your description of phase and polarity isn't.

A difference in phase means a difference in time. A difference in polarity means one signal is going positive while the other goes negative. Phase and polarity are two entirely different things.

It is confusing because if you reverse the wires on one speaker (black to red) in a stereo pair then everybody says the speakers are out of phase. That is technically incorrect. The correct phrase is you have reversed the polarity to one speaker. One will be going in while the other is going out. They still happen at the same time so they are in phase but they move in opposite directions so they have opposite polarities. Unfortunately it is common practice to describe it as the speakers are out of phase, and it is awkward to say that one has its polarity reversed, so we are stuck with a phrase that is technically incorrect.

Same situation with balanced cables. While one line is going positive the other is going negative. Some people incorrectly say they are out of phase but actually one has inverted polarity.

If the speakers aren’t time aligned then there is indeed a phase shift, a difference in time.

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Ralph, I'm glad we have found common ground on the horn issue after butting heads on single ended Vs. balanced, and I understand your point about phase shift in crossovers, but trying to do time alignment by phase shift in crossovers seems to me to be a hopeless affair. The amount of shift is frequency dependent so while I suppose you can shift a driver closer to another as you approach the cutoff frequency wouldn’t that leave you out of phase in the passband of each driver? I’m no speaker/crossover designer so maybe I’m missing something.