If you scroll down the following link it shows a reed that is fixed at both ends as the OP's is, the coil is in a different plane with respect to the reed than the one the OP has, the adjustment nut/screw is shown in the diagram, not sure how the coil arrangement works on the OP's speaker, all the diagrams for these type of speakers seems to show the coil(s) in a plane that is different to the OP's.
http://www.radiomuseum.org/forumdata/use...peaker.pdf
Lawrence.
http://www.radiomuseum.org/forumdata/use...peaker.pdf
Lawrence.
