The PCD tool below is a lot of fun to play around with to see the effects of different crossover order and frequency combinations, combined with driver offsets. You can import actual driver response and impedence for the modeling, or just use the default 90dB/w/m, 8 ohm settings.

Wayne explained it pretty well below, but it's fun to see it in graph format.

Gar.

• Passive Crossover Designer