There's an interesting Voigt Pipes project on the single driver forum that can use the FE166E. I like it because it's really simple to build and looks nice if you have a tolerance for 6' tall enclosures. I built a pair using this as the basis and documented the construction at the link below. We heard these speakers today at the Dallas Audio Club meeting and I believe all who heard them were impressed. After the meeting these speakers followed somebody to their home in Tulsa.