Elements Comparison

Hank's opened-up the "WAR and PEACE" of harpmic lore: The differences found through the production history of SHURE's CONTROLLED-RELUCTANCE and CONTROLLED-MAGNETIC microphone elements. The story's been documented by interested third parties about as well as one could imagine, considering the absence of documentation on record at SHURE BROS. Dedicated souls like Dave Kott at www.greenbulletmics.com have put a great deal of time and energy into what might be called the forensic study of these engines of tone (credit where credit is due)...
IN BRIEF: The SHURE CR went public in 1949, underwent a number of production refinements/simplifications that aided in the unit's production -and certainly reduced manufacturing costs. As for how these changes would apply in the world of the TIN SANDWICH? A very subjective matter, as the element's development and production was never initially paired with harmonica -not until much later, and that move was primarily one from the marketing department.
A FEW CHANGES: The bobbin of the integral transformer went from a four-piece phenolic to a one piece plastic after the CR/CM name change but before the metal collet connecting the foil diaphragm to the center pinion post was swapped-out for a dab of glue. Subjectively, I'd venture to say these two changes can account for at least some degree of variation in the sonic responses found through the CR/CM production periods.
SOME OBSERVATIONS: Again, subjective. The earlier production runs (primarily theCR's) will tend to have an elevated output level. I'll interject at this point that high readings on an ohm meter do not necessarily equate to killer tone or even higher output. Within these production runs there are vast ranges of response and stability. These were not lab instruments, remember. They were intended to replicate speech on a budget ... Various periods of mid and later CM production seem a bit tamer, more stable. The final phase of CM production took place in Mexico and the specs go all over the place. In their defense, I will say I've come across Mexican CM's that sound every bit as strong, every bit as brash, and every bit as gutsy as the best NOS black label CR's I've tested.
WHAT'S IT ALL MEAN?: Let your ears tell you. There is no "BEST", no unified field theory for harp mic elements. Will you actually hear differences? In comparative tests, perhaps. In actual combat situations? Possibly. Arm yourself with knowledge and experience, choose the tools in combinations that work for you. Get busy creating your own myth...