As the Shure microphone product line expanded in the 1930s, Mr. Shure made certain that it was organized, and here is the “secret key”:

100 Series = microphones with carbon elements

200 Series = microphones with ceramic elements

300 Series = microphones with ribbon elements

400 Series = microphones with controlled magnetic/controlled reluctance elements

500 Series = microphones with dynamic elements

600 Series = not used as Electro-Voice had model numbers in the 600’s

700 Series = microphones with crystal elements

800 Series = microphones with condenser elements

Do the above still apply today?  Yes, to a certain extent they do.  Here are examples:

Model 104C has a carbon element.

Model 450 Series II originally had a controlled magnetic element; it was replaced with a dynamic element, but the model number was kept.

Model 545SD-LC has a dynamic element.

What about other current Shure microphone lines?

SM = Studio Microphone, not as in Shure Microphone

BETA = Beta, as in the product line that followed the “alpha” SM line

KSM = Kondenser Studio Microphone, as in “this sounds European”

MX = Microflex, as in small mics with flexible design to handle multiple applications

PG = Performance Gear

SV = Shure Vocal

VP = Video Production

WC = Wireless Countryman

WH = Wired Headset or Wireless Headset

WL = Wireless Lapel or Wireless Lavalier

So now you know the logic behind Shure microphone models numbers!  Thanks to Michael Pettersen, Shure’s Director of Applications Engineering for providing this information.

Born in Cuba of German parents, Ernie joined Shure in 1953 and retired in 1997. During the late 1950s, Ernie developed a new microphone element that would revolutionize the pro audio world, and find its way to every major city, country, and continent…and even to outer space (the SM58 is aboard the International Space Station).  That mic element is the Unidyne III – the engine of the SM58, SM57, 545, and 565.

Before the Unidyne III, all Shure unidirectional microphones were utilized by speaking into the side.  The 545 Unidyne III was the first Shure unidirectional model where the user spoke into the end of the microphone.  An important benefit of an end-fire, cylindrical mic is the uniformity of the polar pattern. This uniformity provides better gain-before-feedback in sound reinforcement systems.  Because sound systems could be louder using the Unidyne III, concert venues could be larger.  This led to concerts in stadiums, as well as large outdoor events like Woodstock in 1969 – where nearly all the microphones were Shure Unidyne III models.  Ironically, Ernie Seeler disliked rock music.

From the Shure 1960 catalog: New! Model 545 “Unidyne III”

The smallest unidirectional dynamic microphone.  Features truly uniform cardioid pickup pattern.    List Price: $85.00    Cable connector: Equivalent to Amphenol MC4M plug   Impedance: Dual. Choice of 50 ohms, 250 ohms, or high.  The Shure Model 545 “Unidyne III” is a new addition to the famed family of Unidyne microphones. This striking-looking, compact, slender , uni-directional, moving-coil microphones features wide-range  reproduction of voice and music and flexibility of uses as hand or stand microphone.  Recommended for dependable use in fine quality P.A. systems, tape recording, fixed-station communications, etc.  Provides highly satisfactory operation under adverse acoustic conditions – reduces or eliminates problems due to feedback and background noise pickup.  Permits placement at a distance from the performer 75% greater than possible with omni-directional microphones.  The 545 is ideal for installations where it is desired to the keep the microphone size and weight to a minimum and still retain maximum operating efficiency.  The 545 “Unidyne III” is rugged – will operate for years without deviation from its original standards.   

Ernie Seeler wanted the frequency response of the Unidyne III to be flat and was disappointed with the rising “presence peak”; he felt it was a flaw.  Yet, the “presence peak” that bothered Ernie became the signature sound of the Unidyne III family of microphones; without it, who knows if the SM58 and SM57 would have become the best-selling mics in the history of pro audio and touring sound.