The phonautograph, patented in 1857, is the first known technology capable of recording sound. The device could transcribe sound waves but not play it back.
The data produced through a phonautograph could help to visually measure and study the waveforms and amplitude envelopes of speech as well as other sounds. It could also be used for comparing the frequency of two simultaneously recorded musical pitches. However, compared to modern recording technology, the phonautograph produced an insubstantial tracing of a two-dimensional line. That is why it could not be played back.
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Scott’s invention of the phonautograph was inspired by the daguerreotype and the anatomy of the human ear.The image shows a simplification of the daguerreotype development process. Image credits: Susanna Celeste Castelli/DensityDesign Research Lab via Wikimedia
His understanding of human anatomy also came into play when inventing the phonautograph. The device was analogous to the human ear and had parts that resembled the ear canal, ossicles, and eardrums. After experimenting with several versions, Scott finally settled on a design that had a funnel-shaped horn or an open-ended barrel to mimic the ear canal. At the small end of the horn or barrel, he attached a flexible parchment to simulate the functions of the eardrum. A lightweight stylus, originally a pig bristle, was attached to the membrane. The stylus would be connected via an indirect linkage, which would serve as the ossicles.
A moving surface of glass or paper was coated with lampblack which is carbon deposited on a surface. The design allowed the simulated ear to pick up sound and transmit it to the bristle which would then trace a line on the lampblack surface. The line would also modulate according to the changes in air pressure. This would create a graphic representation of the sound waves much like a seismograph picks up earthquakes.
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French poet and inventor Charles Cros was the first to realize that recordings made on a phonautograph could be turned into sound. However, before he could work on it, Thomas Edison announced the phonograph.(Image 1) Phonograph Catalog/Advertisement. (Image 2) Edison Home Phonograph. Image credits: Library Of Congress
The idea was that the tracing would be photoengraved on a metal surface for creating a playable groove. Then a diaphragm and stylus would be used for reversing the recording process and recreating the sound. However, before this theory could be put into practice, Thomas Edison announced his invention, the phonograph, which was more advanced technology. The phonograph indented sound waves into a tinfoil sheet, which is why the recording could be played back almost immediately.
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The phonautograph recordings were finally turned into audio in 2008, almost 150 years after they were first recorded.
They turned over their findings over to the Lawrence Berkeley National Laboratory and used a software program called “IRENE.” The program specialized in extracting sound from the wax cylinders without ever needing to touch the delicate surface. Using the software, the team was able to produce high-quality images of the recording. Then, thanks to modern image processing capabilities, the recording was played back as audio for the very first time.
At first, it sounded like a child or young woman was singing the folk song âAu Clair de la lune.â However, after modifying the audio, they realized that it was a man (possibly the inventor himself) singing. To bring the audio to life, they used various techniques such as noise reduction, quantizing, and tuning. They also stretched the recording to a more natural timing, cleaned up the harmonics, and added a stereo effect and reverb to digitally enhance the audio.