Emilio Segrè Visual Archives

More than 30,000 photos of scientists and their work

Attention ESVA Patrons:

The Emilio Segrè Visual Archives’ site is moving soon and adopting an open access approach to digital image sharing. Once we have transitioned to the new site in 2021, we will no longer charge for our high-resolution digital images or usage fees (note that we do not hold copyright to all the images in our collections and you will still need to obtain permission for those which we do not own).

If you are working on a long-term project, we advise you to wait until the migration is complete so that you may obtain our copies for free. If you cannot wait, email us at nbl [at] aip.org and we will do what we can to assist you. We will not be offering refunds for past purchases.

For more information, please visit our FAQ page on the Ex Libris Universum blog. 

Bell Labs F4

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Bell Labs F4

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We charge a usage fee per photo if the photo is published, reproduced in a product or publicly exhibited. This is not a license in the legal sense. As a non-profit institution, we do not make any money providing these photographs. It is only by assessing usage fees that we are able to cover the cost of providing publication quality copies of our photos, preserving the photograph collection according to archival standards, and providing access to the collection by maintaining an online image database. The copyright holder may charge a fee in addition to our service fee.

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Image title: 
Bell Labs Sound Experiments
Credit line: 
Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Physics Today Collection

Caption reads: "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."

Photo date: 
circa 1960
Original format: 
1 photographic print (black and white; 8 x 10 inches)
Bell Labs Innovations