Quote Originally Posted by Deward Hastings View Post
That's only partially true (or is a matter of perspective) . . . all the "two way" designs we see are three way if they are used, *as they all should be*, with a "subwoofer" and crossed out at 100 Hz. or above. It almost always substantially cleans up the midrange to get the distortion inducing high-excursion bass signal off the midrange cone.

Other advantages are:

* One can get rid of that silly hole in the box that lets delayed reflection of the back wave out into the room

* The generally smaller "two way" box (if low bass is not part of the design) is more easily reinforced to stop panel vibrations (or it can be included in the "subwoofer" box as an all-in-one two-way+(sub)woofer)

* It encourages treating the room's behavior in the modal region and the speaker's behavior above as the two separate problems that they are
I guess that my definition of a three way speaker design assumes a completely passive crossover network. I understand the advantages of adding a subwoofer to a two-way system and actually recommend this configuration for anybody who has a home theater setup or any system that includes bass management within the receiver to remove the bass signals from the two-way speakers completely.

I still think that the complications of integrating a subwoofer to a two-way speaker are quite a bit different than what needs to be considered when choosing driver location, crossover frequency and crossover slope in a traditional passive three-way speaker design.... especially since you don't have quite as much freedom when it comes to locating the woofer as compared to a subwoofer which usually operates at frequencies whose wavelengths are so long that they don't need to be located as close to the "midrange/midwoofer" and there shouldn't be any sound that can be localized (other than harmonic distortion that might be present).