To be honest, this mic is a bit of a mystery to me. It’s definitely omni, with no proximity effect, which is probably one of the reasons why harmonica players like this microphone for cupped, handeld playing style. It has a peculiar frequency response. Check out the graph-
After pouring over the literature, I believe this mic is a Shure 430, part of the 400 series of “Commando” mikes, so named for their durability and green finish. The operating principle is described as Controlled Magnetic, which might be moving coil, but I’m not certain.
In addition to harmonica, I like this mic for re-amping, as a room mic, or anytime we want something to sound really different. Plus it looks retro cool, which has nothing to do with the way it sounds, but might inspire a great performance.
Follow this WordPress blog, or via Twitter or Facebook to to guess all of the microphones in this series.
The giant list of discontinued Shure microphones is like a walk through time.
Index to the whole Name That Mic series.