History

Predecessors to the phonograph

Several inventors devised machines to record sound prior to Thomas Edison's phonograph, Edison being the first to produce a device that could both record and reproduce sound. The phonograph's predecessors include Édouard-Léon Scott de Martinville's phonautograph, andCharles Cros's paleophone. Recordings made with the phonautograph were intended to be visual representations of the sound and were not to be reproduced as sound until 2008. Cros's paleophone was intended to both record and reproduce sound but had not been developed beyond a basic concept at the time of Edison's successful demonstration of the Phonograph in 1877.

The phonautograph

Main article: Phonautograph

Dictionary illustration of a phonautograph. The barrel is made of plaster of paris.

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Direct tracings of the vibrations of sound-producing objects such as tuning forks had been made by English physician Thomas Young in 1807,^[8] but the first known device for recording airborne speech, music and other sounds is the phonautograph patented in 1857 by French typesetter and inventor Édouard-Léon Scott de Martinville. In this device, sound waves traveling through the air vibrated a parchment diaphragm which was linked to a bristle, and the bristle traced a line through a thin coating of soot on a sheet of paper wrapped around a rotating cylinder. The sound vibrations were recorded as undulations or other irregularities in the traced line. Scott's phonautograph was intended purely for the visual study and analysis of the tracings. Reproduction of the recorded sound was not possible with the original phonautograph.

In 2008, phonautograph recordings made by Scott were played back as sound by American audio historians, who used optical scanning and computer processing to convert the traced waveforms into digital audio files. These recordings, made circa 1860, include fragments of two French songs and a recitation in Italian.^[9][10]

The paleophone

Charles Cros, a French poet and amateur scientist, is the first person known to have made the conceptual leaps from recording sound as a traced line to the theoretical possibility of reproducing the sound from the tracing and then to a definite method for accomplishing the reproduction. On April 30, 1877, he deposited a sealed envelope containing a summary of his ideas with the French Academy of Sciences, a standard procedure used by scientists and inventors to establish priority of conception of unpublished ideas in the event of any later dispute.

Cros proposed the use of photoengraving, a process already in use to make metal printing plates from line drawings, to convert an insubstantial phonautograph tracing in soot into a groove or ridge on a metal disc or cylinder. This metal surface would then be given the same motion and speed as the original recording surface. A stylus linked to a diaphragm would be made to ride in the groove or on the ridge so that the stylus would be moved back and forth in accordance with the recorded vibrations. It would transmit these vibrations to the connected diaphragm, and the diaphragm would transmit them to the air, reproducing the original sound.

An account of his invention was published on October 10, 1877, by which date Cros had devised a more direct procedure: the recording stylus could scribe its tracing through a thin coating of acid-resistant material on a metal surface and the surface could then be etched in an acid bath, producing the desired groove without the complication of an intermediate photographic procedure.^[11] The author of this article called the device a "phonographe", but Cros himself favored the word "paleophone", sometimes rendered in French as "voix du passé" (voice of the past) but more literally meaning "ancient sound", which accorded well with his vision of his invention's potential for creating an archive of sound recordings that would be available to listeners in the distant future.

Cros was a poet of meager means, not in a position to pay a machinist to build a working model, and largely content to bequeath his ideas to the public domain free of charge and let others reduce them to practice, but after the earliest reports of Edison's presumably independent invention crossed the Atlantic he had his sealed letter of April 30 opened and read at the December 3, 1877 meeting of the French Academy of Sciences, claiming due scientific credit for priority of conception.^[12]

Throughout the first decade (1890–1900) of commercial production of the earliest crude disc records, the direct acid-etch method first invented by Cros was used to create the metal master discs, but Cros was not around to claim any credit or to witness the humble beginnings of the eventually rich phonographic library he had foreseen. He had died in 1888 at the age of 45.