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Alexander Graham Bell's Audio Recordings Heard 130 Years Later

RF Cafe University"Factoids," "Kirt's Cogitations," and "Tech Topics Smorgasbord" are all manifestations of my ranting on various subjects relevant (usually) to the overall RF Cafe theme. All may be accessed on these pages:

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Alexander Graham Bell's Audio Recordings Heard 130 Years Later - RF Cafe SmorgasbordIf you had to guess, what would you say the image to the left represents? Part of a printed spiral inductor? How about a printed antenna for near field communications (NFC)? Need a hint? OK, the object is part of a project that Alexander Graham Bell, his cousin Chichester Bell, and Charles Sumner Tainter worked on in their Volta Laboratory Associates labs. No, it's not a neatly wound coil of telephone cable. It is a section of an audio recording etched on a glass platter in November of 1884. After being stored at the Smithsonian Museum for 130 years, this and a few other recording media was lent to the scientists at Lawrence Berkeley National Laboratory with hopes that they could apply newly invented noninvasive, non-contact techniques to scan the disc and use software algorithms to recover the data. Thomas Edison had introduced his phonograph to the world in 1877, after which many people attempted to improve on his system both for recording and playback. About 200 of the Volta Lab recordings are in the Smithsonian's collection of around 400 of the earliest recordings ever made on a variety of materials.

Alexander Graham Bell's Audio Recordings of "Barometer" - RF CafePer National Museum of American History curator Carlene Stephens, "These recordings were made using a variety of methods and materials such as rubber, beeswax, glass, tin foil and brass, as the inventors tried to find a material that would hold sound. We don't know what is recorded, except for a few cryptic inscriptions on some of the discs and cylinders or vague notes on old catalog cards written by a Smithsonian curator decades ago."

What took so long for work to begin on this and other archived recordings? Mainly it was the lack of a process for recovering the embedded data without risking damage to or destruction of the often fragile media. Berkeley Lab's approach creates a high-resolution digital map of the disc or cylinder. This map is then processed to remove evidence of wear or damage (e.g., scratches and skips). Finally, software calculates the motion of a stylus moving through the disc or cylinder's grooves, reproducing the audio content and producing a standard digital sound file. If you look closely at the glass disc, you can see jagged edges in the spiral pattern that represent the complex voice print that was extracted for processing. For more information, visit irene.lbl.gov.

So, what message did Messrs. Bell, Bell, and Tainter consider important enough to place on this one-of-a-kind recording? Was it a secret password revealed only to 33rd-degree Freemasons, the key to accessing an underground treasure chamber containing the National Treasure, or maybe the code for President Chester Arthur's nuclear football? Maybe... but only if that word - yes, a single word - was "barometer." Barometer. That's it. All that work for "barometer." If you say that word on the phone or in an e-mail, know that the NSA's ECHELON program will be watching you forevermore.

Listen to it here:

Bar-om-et-or. Bar-om-et-or. Bar-om-et-or. Bar-om-et-or. Bar-om-et-or. Bar-om-et-or.


Contact Information

The National Museum of American History collects, preserves and displays American heritage in the areas of social, political, cultural, scientific and military history. To learn more about the museum, visit https://americanhistory.si.edu/. For Smithsonian information, the public may call (202) 633-1000, (202) 633-5285 (TTY).



Posted July 3, 2020
(updated from original post on 12/15/2011)

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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

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