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From the Shure Archives: Unidyne Microphone Prototypes

Corporate Historian Michael Pettersen shares the stories behind some of his favorite archival treasures.
October, 17 2017 |

With thousands of treasures to choose from in the Shure Archives, it's impossible to say which are the most important. Each has a story. In this series, I'll share with you some of my personal favorites, starting with the Unidyne® Prototype Display Case.

Meet Michael Pettersen, Shure Director of Corporate History

Since 1976, I have worked at Shure on teams from sales to product management to applications engineering. Music performance and history are my passions. In 2016, these worlds coalesced when Shure President/CEO Christine Schyvinck decided the company needed a corporate historian. She asked me if I was interested, and I accepted without hesitation.

My involvement with documenting Shure history dates back to 1995. The company's 75th anniversary was looming in 2000. To commemorate it, I suggested a book celebrating the company's history. Much of the content came from a small, crowded archive closet.

Today the Shure Archives have a dedicated space. Corporate Archivist Julie Snyder maintains the collection. Together, we preserve the history that Mr. Shure and Mrs. Shure held so dear.


The Unidyne Prototype Display Case

Unidyne Display Case

In 1925, S.N. Shure opened a one-man radio parts catalog operation in downtown Chicago. When the Great Depression gripped the nation in 1929, the Shure Radio Company became Shure Brothers Company, the exclusive distributor for Ellis Electrical Laboratory, a small microphone manufacturer.

By 1932, Shure began manufacturing its own line of microphones. In 1939, the company made an indelible mark on the audio world with the introduction of the first single-element dynamic directional microphone. The Unidyne was an instant success.

Using the Uniphase acoustical system, the patented Unidyne was the first microphone to provide directional characteristics using a single dynamic element. This breakthrough offered lower cost, greater reliability and improved performance for communication and public address systems.

The engine of today's legendary and best-selling SM58® is a Unidyne III cartridge. That makes the Unidyne, now in its seventh generation, one of the most important chapters of the Shure story.

Vintage Picture of Shure Female Employees

For years, a long wooden box wrapped in protective packaging lay undisturbed in the Shure Archives. Julie and I thought we'd seen a similar box in a vintage photo. Using a magnifying glass to examine the photo, we could see that the objects in the box were labeled "First Unidyne Cartridge," "Second Unidyne Cartridge," "Third Unidyne Cartridge" and so on.

We knew that the seventh one was definitely the final cartridge for the Model 55 Unidyne. What we were looking at was the evolution of the cartridge design for the Model 55 Unidyne Microphone, an indispensable key to the company's history.

Other artifacts from the Shure Archives, like Microphone Development Engineer Ben Bauer's 1930s lab books, authenticated the prototypes. A popular exhibit in current tours of the Shure Archives, the display case has been restored according to archivist specifications. Julie says, "If [an item] comes to you in a certain way, we rehab it without changing the way it was originally meant to be seen."

In our in-house publication, Shure Shots, we recast the photo inside the Shure Archives with the company's most senior female Associates standing in for the originals.


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Shure has been making people sound extraordinary for nearly a century. Founded in 1925 and headquartered in Niles, Illinois, we are a leading global manufacturer of audio equipment known for quality, performance and durability. For critical listening, or high-stakes moments on stage, in the studio, and from the meeting room, you can always rely on Shure.

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