User:Fathiya04/Sound recording and reproduction/Bibliography

Sound recording and reproduction
The story of sound recording, and reproduction, began in 1877, when the man of a thousand patents, Thomas Edison, invented the phonograph. His invention was just a sheet of tinfoil wrapped around a cylindrical drum that rotated and moved laterally when twisted by a handle. It passed beneath a touching metal stylus attached to one side of a diaphragm as it moved. The operator talked into a small mouthpiece on the other side of the diaphragm. The diaphragm vibrated as a result of the sound waves focused on it, causing the stylus to change the pressure on the tinfoil.

The tinfoil was embossed with undulations that approximated the pressure patterns of the sound waves as the drum rotated and traveled across the stylus. Placing the stylus at the start of the groove created during recording and winding the cylinder along again was required for playback. The tinfoil's vibrations caused the stylus to move in and out, causing the diaphragm to vibrate, which moved the air in the mouthpiece, reproducing the sound.

Unfortunately, Edison quickly moved on to other things, including the incandescent light bulb, as is often the case with mercurial geniuses. In any case, he viewed his device primarily as a telephone repeater. He appears to have been tone deaf, if not truly hard of hearing, and recording music was not high on his priority list.

Phonograph[edit]
Thomas Edison's work on two other innovations, the telegraph and the telephone, led to the development of the phonograph. Edison was working on a machine in 1877 that would transcribe telegraphic signals onto paper tape, which could then be transferred over the telegraph again and again. The phonograph was both in a cylinder and a disc form.

Phonautograph[edit]
The first device that could record actual sounds as they passed through the air (but could not play them back—the purpose was only visual study) was the phonautograph, patented in 1857 by Parisian inventor Édouard-Léon Scott de Martinville. The earliest known recordings of the human voice are phonautograph recordings, called phonautograms, made in 1857. They consist of sheets of paper with sound-wave-modulated white lines created by a vibrating stylus that cut through a coating of soot as the paper was passed under it. An 1860 phonautogram of Au Clair de la Lune, a French folk song, was played back as sound for the first time in 2008 by scanning it and using software to convert the undulating line, which graphically encoded the sound, into a corresponding digital audio file.

Magnetic Tape Recorder
This work sparked the interest of many engineers, who set out to create magnetic recording systems. Valdemar Poulsen, a Danish telephone engineer, produced the world's first magnetic recorder utilizing steel wire as a recording medium in 1898, ten years after Smith published his proposal. It served as the principal data and program storage input and output device. Magnetic tape, on the other hand, predates computers. It all started in 1928, when it was created for audio storage and then adopted by the radio and recording industries.