TO CAPTURE AND REPRODUCE: A HISTORY OF RECORDING SOUND
From Edison’s breakthrough, to vinyl and beyond, a variety of techniques and materials have been used
The town centre of Sterling, Mass., is marked by the statue of a lamb. It isn’t any old lamb. It represents “Mary’s Little Lamb,” made famous by the nursery rhyme first published in 1830.
The rhyme was supposedly inspired by a real incident when young Mary Sawyer took her pet lamb to school and has subsequently been recited by many a parent trying to lull a child to sleep. But on Dec. 6, 1877, for the first time ever, the celebrated words were heard not from a human mouth, but from a sound recording. Thomas Edison’s recorded voice rang out from his invention, the “phonograph.”
The eureka moment of sound recording occurred some five months earlier when Edison was working on a way to store telephone messages.
The telephone had been invented by Alexander Graham Bell, with the first successful telephone transmission of a human voice taking place in 1876 as Bell spoke into his newfangled instrument, “Mr. Watson come here, I want to see you.”
The key feature of the telephone was a thin membrane equipped with a magnet that vibrated in response to sound and converted speech to variations of an electric current. The current caused a similar vibration in a membrane in the receiver that then produced sound by causing motion of the surrounding air.
Edison’s idea was to attach a needle to the membrane and pull a piece of waxed paper under it as it vibrated. The needle would then etch a pattern into the wax in response to the sound. To reproduce the sound, the exercise would be reversed by having a needle trace the groove in the wax and thereby vibrating an attached diaphragm.
Amazingly, the idea worked, but the sound reproduction was poor. This is when Edison’s genius came to the fore. What the inventor did better than anyone else was to take a fledgling idea and make it work.
Instead of etching a groove into wax paper, he designed a machine that had a sheet of tin foil wrapped around a metal cylinder that could be rotated with a hand crank. Speaking into the machine vibrated a diaphragm in response to the sound and caused an attached needle to engrave a groove in the tin foil as the cylinder was turned. The recording was then played back by rotating the cylinder and having a needle attached to a diaphragm in the speaker follow the etched groove.
Anyone who listened to the mechanical speech was amazed and Edison’s phonograph became a sensation.
However, there were problems. The recorded sound was not very loud and depended on the speed of the hand cranking. This was addressed by introducing a battery-powered clockwork mechanism. A bigger issue was that the tin foil sheet was easily damaged and could not be “played” more than a few times.
To turn a scientific curiosity into a commercial product, a recording medium was needed that could be easily handled and stored without being damaged so that it could be repeatedly played. This was a call for some chemical ingenuity.
Edison hired chemist Jonas Aylsworth to develop an improved material for recording. Aylsworth followed the usual Edison regimen: try, try and try again. He carried out some 700 experiments with a variety of waxes, soaps and fatty acids, eventually coming up with a “brown wax” that could be formed into a sturdy cylinder. Still, each cylinder had to be individually grooved. Further experiments resulted in a “black wax” that when heated could be poured into a grooved mould and then allowed to cool and harden, making mass production of cylinders possible.
Unfortunately, the wax cylinders were susceptible to changes in texture from humidity and generally could produce only a couple of minutes of sound. A more durable material that could support longer recordings was needed.
Edison’s chemists focused on a novel material: celluloid. American inventor John Wesley Hyatt, looking for a substitute for ivory in billiard balls, had combined nitrocellulose with camphor to produce what can be called the world’s first synthetic plastic, celluloid. This turned out to be suitable for the manufacture of cylinders, but the sound produced was scratchy, since the celluloid surface was not smooth enough. The addition of a blue aniline dye surprisingly solved this problem and Edison’s “Blue Amberol” cylinders were born.
They became extremely popular, at least until Emile Berliner introduced discshaped records made of celluloid or hard rubber to be played on his “gramophone.” Discs could hold more music and were more easily stored. Then in 1895, Berliner switched to making his discs out of shellac, the resin secreted by the female lac bug, allowing for the largescale economical production of records. Edison had to switch to discs to compete and was bent on finding an improvement over shellac.
Leo Baekeland in 1906 had made “Bakelite,” a synthetic plastic by combining phenol and formaldehyde. This seemed to be suitable for records, but the process was plagued by the contamination of the plastic with moisture formed during the reaction. Aylsworth solved this problem by developing a process that produced the plastic at a lower temperature and discovered that the addition of hexamethylenetetramine prevented the formation of water vapour during the moulding process. The novel material was termed “condensate” and was superior to shellac, but proved to be too expensive and shellac discs held sway.
Finally, in 1929 Edison threw in the towel and gave up on the production of records.
Shellac records remained the mainstay of the industry until 1948, when polyvinyl chloride (PVC) records were introduced. These were less brittle, held more music and produced fewer cracking sounds. Subsequently they were replaced by polycarbonate compact discs and finally by electronically downloaded music.
And yes, you can now download Edison’s original recording of “Mary had a little lamb” and take a little audio stroll through history.