Audio Artifacts: When Shure Joined the Allied Forces

On December 8, 1941, a day after the bombing of Pearl Harbor, the United States declared war on Japan. Four days later, Germany and Italy, Axis nations allied with Japan, declared war on the United States. On December 11, 1941, the United States, through a Congressional Joint Resolution, became fully engaged in the Second World War.

In January 1942 — just a month after the attack on Pearl Harbor — US President Franklin D. Roosevelt ordered the establishment of the War Production Board. Its purpose was to convert peacetime industries into factories manufacturing weapons and military equipment. The second goal was to conserve materials like metal, which US soldiers, sailors and Marines would need for the fight in such things as guns, tanks, ships, aircraft, and tactical vehicles. 

Shure Brothers, along with Western Electric, Electro-Voice, Universal, and other American electroacoustics companies re-tooled their manufacturing operations, and became suppliers of military acoustical transducers, such as microphones and headphones.

From 1941 to 1943, the number of Shure employees grew from 100 to 1,000. Manufacturing lines, once dedicated to producing the Unidyne I microphone, introduced just three years earlier, operated up to 24 hours a day to keep up with the wartime demands for military products.

The Allied Forces relied so heavily on the devices manufactured by Shure that employees, eager to join the fight overseas, were often excluded from active service. The company had become a leading supplier of microphones used by all branches of the US military, plus the British and Soviet forces.

Combatting cockpit noise

Plane to plane communication and plane to ground communication became a critical issue as World War II intensified. Noise in the cockpit made it difficult for the pilot to hear incoming messages and to transmit intelligible outgoing messages.

The US government turned to Harvard University’s Cruft Laboratory. One of the acoustics experts there was a young Leo Beranek – later the founder of consulting firm Bolt, Beranek, and Newman – and arguably one of the most important acousticians of the 20th century. His research led to critical advancements in speech intelligibility for battle communications.

The T-30 throat microphone was developed along with the ANB-M-C1 (Army Navy British – Microphone – Carbon) oxygen mask mic. Shure engineer Ben Bauer collaborated with Beranek on enhancements to these technologies. 

Shure manufactured hundreds of thousands of microphones to the military’s exacting specifications. According to a February 1945 Shure Shots intra-company newsletter, the closing phase of the war continued to demand production of military products as well as the company’s Unidyne mics: “Today our so-called peacetime or commercial line microphones are important in the war we are waging. There is a still a need for battleships, intercommunications systems on ships, hospitals, rehabilitation centers, USO camps, training schools – they require Unidynes, Uniplexes, phonograph pickups, hearing aids, and other Shure products.”

T-30-V Throat Microphone

The acoustic noise in a World War II fighter plane cockpit was so excessive that existing commercial microphones were nearly useless. The pilot’s words were not intelligible, buried in ambient noise estimated at 115 dBA sound pressure levels and above. 

Both sides of the conflict employed throat mics (also called laryngophones). They eventually became standard equipment for all warplanes since they responded to the physical movement of the pilot’s larynx and not to the vibration of air molecules.

The T-30 mic utilized two carbon transducer elements. The pilot strapped the T-30 around his neck and as he spoke, the vibration of the larynx moved the carbon granules inside the elements. To increase the vibration transmission strength, the pilot often pressed the T-30 tightly against his throat.

At the peak of World War II demand, Shure manufactured more than 1,000 T-30-V units every day. Vintage mic enthusiasts will find that “new old stock” examples are regularly sold on auction sites. Shure purchased a pristine example for $50 in July 2021. It worked (of course) and looked as if it had just rolled off the assembly line. 

Throat mics are still in use today, favored by law enforcement and emergency personnel wearing oxygen masks, protective gear, or working in loud, emergency situations. And here’s a surprise: beatboxers like them, too.

ANB-M-C1 Oxygen Mask Microphone

The ANB-M-C1 was designed for safe operation in the highly explosive environment inside a pilot’s oxygen mask. Though unlikely, a spark from a microphone could have disastrous results. Additionally, the mic was engineered to perform in the cold, thin air of high altitudes.

Like the T-30, it utilized a carbon mic element, chosen because it was durable, reliable, and produced a very “hot” signal level that would drive the pilot’s radio to full modulation.  It was also inexpensive to manufacture and did not require the use of scarce metals/materials that were critical to the wartime effort.

Because the ANB-M-C1 microphone had to be carefully installed inside the mask, every ANB-M-C1 was shipped with precise instructions. Was this warning truly necessary?

“CAUTION: If the microphone is removed from mask, the hole in the microphone cavity must be plugged in for the oxygen mask to function.”

Seventy years later, it is not unusual for an ANB-M-C1 to still function and meet the published specifications. 

The Army-Navy E Award

On April 18, 1943, the women and men of Shure were presented the prestigious Army-Navy “E” award for “high achievement in the production of war materials.” Robert Patterson, Under Secretary of the War, wrote, “The production standard you are setting is inspiring, and will serve as an example to all Americans.”S.N. Shure stated, “Here, at Shure Brothers, we have a cross section of the American people. We are a peace-loving people who were unprepared for war. We loved peace, but we love liberty even more.”

The Army-Navy “E” award pennant now resides in the Shure Archives.

Legacy of United States Military Standard (MILSPEC) at Shure

Shure quality was built into every military transducer that left the factory. For S.N. Shure, this was a formidable responsibility as the product bore his family name. It was not an “Acme” microphone; it was not an “Acoustic Apex” microphone; it was a “Shure” microphone. The safety of Allied military personnel depended upon the proper operation of acoustical devices that displayed the Shure brand.

A Company memo stated: “Those screws, washers, and other small parts mean the difference between life and death to millions of fighting men in the widespread battle lines of the Allied Forces.”

When World War II ended, S.N. Shure decided to retain military quality specifications for peace-time products. Military quality specifications resulted in lower scrap rates during manufacturing, fewer products returned for repair, improved product reliability …and customer loyalty to the Shure brand.

Ask an SM58® owner to describe the microphone in one word and that word often is “reliable.” The seeds of Shure reliability, taken for granted today, were sown during the war.