This is a continuation of the impulse response subwoofer thread. Here are some screens from Sounds Systems: Optimaztion and Design that deal with phase alignment of crossovers.
The figure above shows the phase responses brought together between sub and main. The crossover is not steep and therefore the phase response overlap over a wide range.
The LF and HF components of a 2-way xover
The combined response of a 2-way xover