Huh, ribbons.... My love-hate relationship for many years and for some still to come. I made quite a few of different configurations. Still, I am fascinated--they look so simple, but they are so hard to design well. OK, nevermind.
Mark, there is no such thing as a monopole magnet. It is like--if you have top, there is a botom; if you have left, there is right; if you have N, you should have S. There are different ways of arranging magnets in ribbons, and if you see something like N-S, it means that opposite sides of magnets gonna be S-N. You can connect them by means of some kind of magnetic return circuit to make the magnetic field stronger.
The transformer, which is a very important part of the ribbon mic, is usually about 1:40 ratio. As Han has already mentioned, it serves as a impedance matcher, but also steps up a very low signal (it is really low) induced by the ribbon. Preamp is also a very big issue. Because of low sensitivity of the mic, it should be very quiet. To get the most of the ribbon mic, the impedances should be very carefully matched, often by means of transformer coupling. Some ribbon mics are designed to work with unloaded transformer inputs...
Huh, so much to say... First, try to make a search. we had some discussions on ribbons in the past...
