I cut the motor frame from some salvaged aluminum. Epoxied in some N42 2" by 1/4. Used 1.8u foil and a CM9887 transformer. The body is buck antler I drilled out and stuck a shortened XLR in. I used copper mesh from mcmaster Carr and the mesh frame is brass. Freeform design but it sounds good through the UA610 channel i built. To corrugate the ribbon I used some brass gears from a mechanical circuit timer. Ribbon gap is about 3/10ths of an inch. length 2"