The theory and application of audio measurement systems was focused on in the May 1984 issue of Sound & Video Contractor. The cover featured a digitized image of a TEF System 10 TDS display.

Starting off, Richard Cabot supplied an in-depth primer about measuring audio. In it he covered many aspects of audio measurement, including distortion and noise, as well as the types of equipment required to make those measurements.

Noland Lewis and Tim Purcell provided a practical case study of using a TEF system to measure the system at the Orpheum Theater in San Francisco. Lewis and Purcell started with a brief overview of measurement systems (at that time, there really wasn't much available, so it had to be brief) and then introduced the concept of TEF (TEF is an acronym for time, energy, frequency). Lewis was — and remains — president of ACO Pacific, a manufacturer of measurement mics and related equipment, and Purcell was the owner of Purcell Audio in San Francisco. Purcell still owns Purcell Audio.

“What Are We Really Measuring?” by Marshall Long discussed Time Delay Spectometry measurement performed on a — you guessed it — TEF system. In his article, Long went into more detail about the TEF system: what it was made up of and how you used it. Long is president of Marshall Long Acoustics, a consulting firm he founded in 1971. At that time, he was also a technical consultant in acoustical design for Sound & Video Contractor.

“Basic Real Time Analysis” provided a listing of some of the manufacturers of sound-level meters, analyzers, and test equipment. In that section, two authors provided closer looks at a couple of analyzers of the day. William Cheney offered a look at the Goldline model 30, ⅓-octave RTA. In addition, Larry Driskill discussed the value of a spectrum analyzer (in this case, an Ivie IE 30) in “The Sound Contractor's VOM.”

Telex 6120 duplicator

Tecron's TEF System 10, featured throughout the issue, also had an ad in the magazine. In 1984 TEF was sold by Tecron, which was a division of Crown International. TEF is now a division of Goldline. The TEF System 10 was a self-contained computer that had 96K RAM, two floppy-disk drives (the 5¼-inch size), and a built-in monitor (about 5 inches) enclosed in a pretty hefty metal case. The front protective cover flipped down and was the keyboard. In 2004 the TEF System 20 is a one-rackspace interface unit controlled by an auxiliary computer. The System 20 has 64K RAM, and the requirements for the aux computer are minimum 4 MB of RAM with 8 being recommended.

Telex Communications advertised its 6120 duplicator, a high-speed reel-to-reel and cassette tape duplicator, in the May 1984 issue. The large reels of tape prominently shown certainly date the ad in comparison with today's digitally dominated duplication market.

In 1984 Telex was well known for its communications and intercom systems and tape duplication systems. Today Telex umbrellas seven major pro-audio manufacturers (Telex, Dynacord, Electro-Voice, Klark Teknik, Midas, RTS, and University Sound). Products under the Telex logo encompass computer audio, telephone conference systems, digital duplication, wireless systems and networks and communications systems for commercial and military applications.

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