The web site does have a lot of choices. That, in itself, makes things sort of confusing. But there are just a few basic designs, and they are populated with different drivers. There are traditional bass-reflex speakers, bass-reflex speakers with matched directivity, constant-directivity cornerhorns and free-standing folded horns.one π is a bass-reflex speaker with an 8" woofer
two π is a bass-reflex speaker with 10" woofer
three π is a matched-directivity bass-reflex speaker with 12" woofer
four π is a matched-directivity bass-reflex speaker with 15" woofer
five π is a constant-directivity cornerhorn with a 10" woofer
six π is a constant-directivity cornerhorn with a 12" woofer
seven π is constant-directivity cornerhorn with a 15" woofer
Studio Series use Eminence Alpha woofers
Thermionic also uses Eminence Alphas
Theater uses Eminence Deltas
Stage Series uses Eminence Omegas
Premium Stage uses Eminence Kilomax
Professional uses JBL Professional Series drivers
I hope that clarifies things a bit.