A Sound Idea
Photos of the Month — August 2014
Did you know that August is Audio Appreciation Month? From the photophone to the iPhone, the way we communicate seems to evolve as fast as the speed of sound. With the Acoustical Society of America being one of AIP’s 10 membership organizations, we thought we’d take a moment to highlight innovations made in the field of acoustical physics. Our six featured images span from Bell Laboratories’ Oscar II to present-day inventions like the Electret Microphone. These and many more images can be found on this site. Please enjoy this featured selection from our historical photos collection. To see more images like the ones we’ve selected, type the word “sound” in the search engine.
“B. F. Logan (left) of Bell Telephone Laboratories adjusts an artificial reverberation filter (unit with handgrips, center) to obtain an all-pass characteristic — that is, an equal response for sound at all frequencies. Manfred Schroeder (right), who supervises acoustics research at the Laboratories, subjectively evaluates the quality of the reverberated sound. Both researchers are perfecting a truly ‘colorless’ artificial reverberator.”
Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Physics Today Collection.
These two drawings indicate the apparatus used in the photophone and depict how speech travels. One is a man sitting in a chair blowing into an object so the sound goes to the other end of the table. The other depicts two men; one with ear phones and the other speaking into a big round object. Alexander Graham Bell’s photophone modulated reflected sunlight with sound vibrations, then detected the sound by using the light to illuminate a piece of selenium. It carried voices without wires, but not very far. Circa December 1880.
Bell Laboratories / Alcatel-Lucent USA Inc. / Collins Radio Company, courtesy AIP Emilio Segrè Visual Archives, Hecht Collection.
“Two heads are better than one for Bell Telephone Laboratories research into the ways people locate the direction of sound. Practical results of the recent ‘double dome’ research at Murray Hill, NJ, may be the improvement of stereophonic radio and TV programs, which are transmitted nationwide over telephone facilities. In the experiments, two microphones in the ears of the dummy, ‘Oscar II’ were substituted for human ears. Oscar’s head reproduced the ‘shadowing’ of sound by a human head. Persons participating in the tests -- such as Mary Lou Hartig, shown -- wore the extra head so that motions of their heads would be reproduced, for even very small movements influence hearing. The natural sounds received in each microphone were altered electronically by acoustics scientist, R. L. Hanson (right) and were delivered to the earphones. Listeners were asked to point to the apparent direction of the altered sound. Normally, the ear that is closer to a sound hears it earlier and louder than the other ear. Here, however, artificial differences in time delays and intensity were introduced, and it was found that the factor of intensity is more important than previously believed. If sound reaches one ear first but reaches the other ear somewhat louder, the hearer is completely confused.” 1960.
Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Physics Today Collection.
Inventor of the Electret Microphone, James E. West. Acoustical Society of America (ASA).
AIP Emilio Segrè Visual Archives.
On June 9, 1922, in lecture room 100 of the Physics laboratory at University of Illinois- Urbana Champaign, Professor Joseph T. Tykociner gave the world’s first public demonstration of sound-on-film movies. His work caused the old system of “pictures on film, sound on phonograph discs”, to be discarded. Tykociner is behind the desk, looking at the horn microphone. Beside him is the first sound-picture camera. At far right of the table is the first sound-picture projector. Headphones hanging from the table or a loudspeaker were used to hear the sound. June 9, 1922.
Department of Physics, University of Illinois at Urbana-Champaign, courtesy AIP Emilio Segrè Visual Archives.
Vivian Leroy Chrisler, of the Bureau of Standards, sits in a box in the sound laboratory while studying the echo-producing properties of conditions found in talking picture theaters. The box prevents his clothing from intervering with the tests; note that the ‘audience’ sits in typical movie theater seats. Circa 1930.
AIP Emilio Segrè Visual Archives.
