Dictation machine

A dictation machine is a sound recording device most commonly used to record speech for playback or to be typed into print. It includes digital voice recorders and tape recorder.

The name "Dictaphone" is a trademark of the American Graphophone Company, but it has also become a common term for all dictation machines, as a genericized trademark.

Alexander Graham Bell and his two associates took Edison's tinfoil phonograph and modified it considerably to make it reproduce sound from wax instead of tinfoil. They began their work at Bell's Volta Laboratory in Washington, D.C. In 1879, and continued until they were granted basic patents in 1886 for recording in wax.

Thomas A. Edison had invented the phonograph in 1877, but the fame bestowed on him for this invention — sometimes called his most original — was not due to its efficiency. Recording with his tinfoil phonograph was too difficult to be practical, as the tinfoil tore easily, even when the stylus was properly adjusted. Although Edison had hit upon the secret of sound recording, immediately after his discovery he did not improve it, allegedly because of an agreement to spend the next five years developing the New York City electric light and power systems.

By 1881 the Volta associates had success in improving an Edison tinfoil machine to some extent. Wax was put in the grooves of the heavy iron cylinder, and no tinfoil was used. The basic distinction between the Edison's first phonograph patent, and the Bell and [Charles Sumner] Tainter patent of 1886 was the method of recording. Edison's method was to indent the sound waves on a piece of tinfoil, while Bell and Tainter's invention called for cutting, or 'engraving', the sound waves into a wax record with a sharp recording stylus.

Among the later improvements by the Volta Associates, the Graphophone used a cutting stylus to create lateral zig-zag grooves of uniform depth into the wax-coated cardboard cylinders, rather than the up-down vertically-cut grooves of Edison's contemporary phonograph machine designs.

Notably, Bell and Tainter developed wax-coated cardboard cylinders for their record cylinders, instead of Edison's cast iron cylinder, covered with a removable film of tinfoil (the actual recording medium, which was prone to damage during installation or removal). Tainter received a separate patent for a tube assembly machine to automatically produce the coiled cardboard tubes, which served as the foundation for the wax cylinder records.

Besides being far easier to handle, the wax recording medium also allowed for lengthier recordings and created superior playback quality. Additionally the Graphophones initially deployed foot treadles to rotate the recordings, then wind-up clockwork drive mechanisms, and finally migrated to electric motors, instead of the manual crank that was used on Edison's phonograph. The numerous improvements allowed for a sound quality that was significantly better than Edison's machine.