Category: Tech Topic

Guest author Robin Magruder worked at Showco for 29 years, rising from Roadie to Executive VP/General Manager. Today, Robin is President and General Manager of Crossroads Audio, Dallas, Texas. Robin kindly offered his recollections of the Unidyne IV Model 548 and its use by Showco. “Showco started using the Model 548 microphone about 1970. I’m certain Showco was indeed Shure’s largest 548 customer – probably by far. I believe there were several reasons Showco chose the 548. It was rugged,… -more-

Originally posted October 2018, this updated Tech Tip #548 is reissued in homage of the Model 548. Let’s begin with a brief history of the Unidyne family: 1939: Shure Model 55 Unidyne I – world’s first unidirectional, single element, moving coil dynamic microphone. A revolutionary breakthrough in the science of electroacoustics. Earns a patent for Ben Bauer in 1941. Garners the IEEE Milestone Award in 2014. 1951: Shure Model 55S Unidyne II – advertised as “The Microphone That Needs No… -more-

As for me, I am tormented with an everlasting itch for things remote.”― Ishmael, from Moby-Dick, or The Whale by Herman Melville Loyal readers, avast and behold a great white whale that proved elusive for decades. Vagabond 88 T schematic Gaze upon the long-concealed 1953 circuit for our wireless Vagabond 88T transmitter – the world’s first handheld wireless microphone. This diagram, never available to the public, was found January 30, 2024, in a banker’s box stored offsite for over sixty… -more-

The film “Oppenheimer” has piqued interest in the Manhattan Project, the labs at Los Alamos, the Trinity test, and the complex personalities responsible for creating the atomic bomb. Today’s Tech Tip links Shure to the Manhattan Project. “Fat Man” bomb, detonated August 9, 1945 Shure microphones and military headphones were deployed at Los Alamos during World War Two. Our mics were used for two-way radio, intercom, direct-to-disc recording, and public address, though photographic evidence is difficult to obtain because of… -more-

Each month features an updated reprise of a Tech Tip from ten years ago because many past Tech Tips are well worth review. Also, some will benefit from updating. Enjoy the thirty-third monthly Tech Tip reprise. There are multiple examples of Shure microphones that were introduced with certain markets in mind, then end users discovered far better ways to employ the mics. The SM58 (Studio Microphone) was aimed at the television and radio market…but rock’ n’ roll live sound engineers… -more-

During each tour of Shure headquarters, I mention crystal microphones – a transducer technology we abandoned over fifty years ago. Guests shake their heads in wonder learning that a tiny sliver of Rochelle salt crystal will produce an audio signal of amazing clarity. Their disbelief increases when they hear that Rochelle salt was developed as a laxative. A lump of Rochelle salt In 1934, Shure introduced its first line of crystal microphones, the 70 Series. Three years later, an attractive… -more-

Loyal readers of Tech Tips may recall that our Company distributed carbon mics from Ellis Electrical Laboratories in 1930/31, and then we began manufacturing Shure branded carbon models in 1932. Shure Model 5B carbon microphone, 1936 As a technical refresher, here is a simplified diagram of a carbon mic element and external circuit: Carbon mic element and circuit The bowl of carbon granules creates a variable resistor whose ohmage changes as the diaphragm [a thin metal circular plate] vibrates against… -more-

Before Shure Brothers Company initiated the manufacturing of its own microphones in 1932, we distributed carbon mics made by Ellis Electrical Laboratory, based in Berwyn, Illinois, a suburb of Chicago. In 1929, S.N. Shure and Hugh Ellis signed an exclusive distribution agreement, with Shure agreeing to purchase a minimum of one hundred microphones in each year of the contract. Subsequently, Shure Brothers Company formed a subsidiary: Ellis Electrical Laboratory Sales Corporation, S.N. Shure – President. In 1930, Shure’s first catalog… -more-

I can envision the puzzlement of many readers.  “How can this be?  A microphone emits a mic level signal, not a line level signal.  Besides, why make such a device? Who needs a mic that emits a line level signal?” First, a quick review.  A mic-level signal is around 1 millivolt = 0.001 volt = -60 dbV.  A line-level signal is 1,000 times greater, or around 1,000 millivolts = 1 volt = 0 dbV.  There is a nominal 60 dB… -more-