Education

TECnology Hall of Fame

Compared to medicine or agriculture, the history of professional audio has been a comparatively short 125 years or so—barely a ripple in geologic time. But a whole lot has happened in that century and a quarter. True, other innovations also emerged in that era—from automobiles to aviation, telephones to television, exploring outer space to cyberspace—but for we true devotees, audio is what counts.

To expand the scope of the 20th annual TEC Awards, the Mix Foundation created a TECnology Hall of Fame to spotlight the long and rich history of the pro audio industry. Selecting just 25 inductees from a 125-year heritage turned out to be a difficult task, indeed. An elite committee of more than 50 industry leaders, engineers, producers, designers, educators, journalists and historians volunteered to help, with the only “rule” being that any selections must be at least 10 years old.

So set your time machine (analog, of course) waaaay back and enjoy this magic carpet ride through the annals of audio.

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1926: Western Electric 555-w First Compression Driver

In 1926, talking motion-picture development was well under way, but with the low-power amps available at the time, high-output reproduction was pretty much out of the question. Given that premise, two Bell Labs engineers, Edward C. Wente and Albert L. Thuras, offered what they described as an acoustical device using a “light piston-type diaphragm” driven by a light rigid coil. The diaphragm/voice coil was set within a dense electromagnetic structure and designed to mount onto a horn.

The resulting Western Electric Model 555-w “receiver” was surprisingly close to modern high-frequency compression drivers, with its 0.002-inch thin aluminum-dome diaphragm, corrugated surround, phase plug and threaded mount for fitting the driver on a variety of horns. Shown on the previous page is the 555-w mounted on a Model 12-A horn having a 45x45-inch throat opening and an 11-foot exponentially tapered pathway. The driver/horn combination proved highly efficient, achieving high SPLs from low-powered amps, whether used alone or with cone woofers for extended low-frequency performance.

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1992: Waves Q10 Paragraphic EQ First Audio Plug-In

The concept of plug-ins—additions that add functionality to established programs—dates back to text editors running on Univac mainframes in the 1970s. By 1991, plug-ins came on the scene, mainly as filter effects sets for paint and photo-manipulation software. Although few realized it then, the audio world was about to see some rather significant changes in the years to come.

At AES 1992, Waves unveiled the first audio plug-in. Created by founders producer Gilad Keren and musician Meir Shaashua (both having extensive math and engineering backgrounds), the Q10 Paragraphic Equalizer was a little before its time. It ran on Digidesign’s Sound Tools and early Pro Tools systems where only a single plug-in could run at a time. Two years later, the advent of TDM opened the possibility of multiple plug-ins on a single session, and software-based signal processing began evolving into an integral part of modern audio production. Today, the Q10 is still going strong (now updated for multiple platforms and 24-bit/192kHz resolution) and is offered in Waves’ high-end production bundles.

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1940 Shure Unidyne Model 55

Seeking to create a low-cost cardioid dynamic microphone, Shure engineer Benjamin Bawmzweiger (he later changed his name to Bauer), began developing the Unidyne in early 1937. Prior to this, most unidirectional patterns were achieved by multi-element mics that combined the outputs of omni and figure-8 capsules via a switch or panpot. The concept worked, but resulted in bulky mics with uneven frequency response and unpredictable directional patterns.

Bauer felt a single-capsule approach was the only workable solution. He experimented with capsules having front and rear openings that allowed sound waves to reach the diaphragm. Partially blocking the rear openings created a short phase delay that effectively cancelled the sounds from the rear. Varying the rear port resistance created various directional patterns—cardioid, hypercardioid and supercardioid—and the Unidyne was born. Debuting in 1940 as the Model 55A/B/C (three versions with different output impedances), the Unidyne was an immediate hit. Nearly 70 years later, it remains in production as the model 55SH—combining vintage looks with a modern capsule.

In 1993, the Shure 55 was immortalized on a U.S. postage stamp honoring the career of Elvis Presley. This watercolor depiction by artist Mark Stutzman shows the young singer cradling the mic, which to this day continues to be known unofficially as the "Elvis mic." This first-class postage issue went on to become the most popular U.S. commemorative stamp of all time.

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1939: Pulse Code Modulation

Discoveries occasionally occur long before the current technology is ready to accept and support them. This is certainly the case with British physicist Alec Harley Reeves, who proposed Pulse Code Modulation (PCM), one of the cornerstone principles of digital audio, more than four decades before the first commercial digital audio recorder.

In his 1939 patent for a Signaling System, Reeves describes a “system for transmitting complex waveforms—for example, speech—wherein the waveform is scanned at the transmitter at predetermined instants” and the “amplitude range of the waveform to be transmitted is divided into a finite number of predetermined amplitude values according to the fidelity required.” He also proposed a tube-based PCM circuit, but this was in 1939—well before the introduction of transistors, ICs or microprocessors—and Reeves’ PCM proposal remained mostly unused until the 1950s, when it was employed in low-fidelity applications such as telephone systems.

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1940 Walter Weber AC Tape Bias

Born 100 years ago, Dr. Walter Weber was a Siemens engineer who was recruited by Dr. Hans Joachim Von Braunmühl to work for Reichs-Rundfunk-Gesellschaft (German Broadcasting) in 1932. While at RRG, von Braunmühl assigned Weber to look into means of improving the performance of AEG Magnetophon tape recorders.

Dr. Walter Weber's research in tape bias eventually helped usher in the acceptance of tape as the world production standard.

However, with the introduction of BASF’s ferric-oxide tape in 1939, the Magnetophon was approaching broadcast standards and one of Weber’s interests was the application of bias currents. Earlier research (such as by Americans Wendell Carlson and Glenn Carpenter in 1921) had shown that adding a high frequency AC bias signal could raise the quality of magnetic recording, but given the poor performance of wire recorders, the improvement was minimal.

During experiments with a DC biasing scheme in the spring of 1940, Weber inadvertently applied a AC current to the recording chain, leading to his rediscovery of the benefits of AC biasing. The effect was dramatic, offering a 10dB improvement in the Magnetophon’s noise floor.

Weber filed a patent (German #743,411) on July 28, 1940, and the AC biasing technology was licensed to AEG, who incorporated it into its Model K4 HF-Magnetophons that launched a year later. And with a frequency response of a then-astonishing 10kHz, tape recording was on its way to eventually become the world production standard.

Interestingly, one of Weber and von Braunmühl's design projects had nothing to do with tape. In 1935, they filed a patent (German #705,827; U.S. patent #2,179,361) for the Braunmühl-Weber dual diaphragm capsule, the first unidirectional condenser mic, which eventually became the Neumann M7 capsule used in the U47. 

In July of 1944, at age 37, Walter Weber suffered a fatal heart attack, but his legacy lives on.