Actually Jim they run pretty cheap. The completely doped/phase-plugged/whizzer cone trimmed/ rewired version sells for under 300$ a pair. He just glues the phase plug onto the former. For 20$ he will e-mail complete set of plans and for another 60or 80$ you get all the other stuff like spikes and the top diffuser plate etc. 60$ for marine grade plywood and you are set, and they require no eq. I liked them better than the Lowther systems I have heard because they are the first true full-range in my experience. I mean if you need a filter, then whats the point? Just build a good two-way. I would recommend them to anyone who doesn't have the room for Pi Theater 4's in their home.