Bell Telephone Labs: Test Tube for Sound
December 1947 Radio News

December 1947 Radio News

[Table of Contents]  These articles are scanned and OCRed from old editions of the Radio & Television News magazine. Here is a list of the Radio & Television News articles I have already posted. All copyrights are hereby acknowledged.

Some people like to demean engineers and scientists for their propensity to want to conduct experiments and obtain measured, empirical data rather than "winging it" and being satisfied with intuitive knowledge or the contemporarily popular term "gut." If mankind had not adopted scientific methods and ventured beyond the so−called cradle of civilization on the African continent, we would all still be living in grass huts, hurling rocks at prey, and foraging for berries. Quantifying and categorizing all things in nature helps inventors create new and improved implements that help make life better. Early on it was mostly individuals like Archimedes, Euler, Newton, and Edison who built the pool of knowledge that fed and evolved into corporations, governments, and universities doing the vast majority of the work. Bell Laboratories is probably one of the most recognizable names for a group of people that collectively produced an immense amount of data and products. This infomercial in a 1947 edition of Radio News is a prime example of the kind of intense, well-planned effort that went into advancing the state of the art of audio communications.

Test Tube for Sound

A telephone listens to a loud speaker in the new "free field" acoustic test room at Bell Telephone Laboratories. The sound-transparent "floor" is built of steel cables.

This giant "test-tube" is actually an echoless sound room at Bell Telephone Laboratories. Here engineers seek new facts about sound which will help them make telephone service still better and more dependable.

Bell scientists know a great deal about what happens to sound in electrical systems. This new room will give them a powerful tool to find out more about what happens to sound in the air.

In an ordinary living room, most of the sound addressed to you comes by way of reflections. At 10 feet less than 10% reaches you directly.

Sound that bounces at you from walls, ceilings, furniture, and your body is all right for hearing - but it poses questions for scientists who would study it uncontaminated by reflections.

The Bell Laboratories "test-tube" gives telephone people the chance to produce pure sound and analyze" it reliably with respect to intensity, pitch, and direction. The entire room is lined with glass wool, contained in wire-mesh cases, wedge-shaped to give maximum absorbing area. Sound bounces along the sloping surfaces, sifts into the soft glass wool, and is gradually stifled.

This is one more example of Bell Laboratories' constant work to learn more about everything which can extend and improve telephone service.

Bell Telephone Laboratories

Exploring and inventing, devising and perfecting for continued improvements and economies in telephone service.

Posted January 25, 2022
(updated from original post on 8/27/2015)