A pure tone is a tone with a sinusoidal waveform.
A sine wave is characterized by its frequency, the number of cycles per second—or its wavelength, the distance the waveform travels through its medium within a period—and the amplitude, the size of each cycle. A pure tone has the unique property that its waveshape and sound are changed only in amplitude and phase by linear acoustic systems.
A pure sine wave is an artificial sound. Hermann von Helmholtz is credited as the first creator of a sine wave with the 'Helmholtz siren', a mechanical device that sends compressed air through holes in a rotating plate. This is presumably the closest thing to a sine wave that was heard before the invention of electronic oscillators.
Sinewaves are generally uncomfortable to the ear, and may cause noise-induced hearing loss at lower volumes than other noises. Sound localization is often more difficult with sine waves than with other sounds; they seem to ‘fill the room’.
Read more about Pure Tone: Fourier Theorem
Famous quotes containing the words pure and/or tone:
“Having thus chosen our course, without guile and with pure purpose, let us renew our trust in God, and go forward without fear and with manly hearts.”
—Abraham Lincoln (1809–1865)
“There was about all the Romans a heroic tone peculiar to ancient life. Their virtues were great and noble, and these virtues made them great and noble. They possessed a natural majesty that was not put on and taken off at pleasure, as was that of certain eastern monarchs when they put on or took off their garments of Tyrian dye. It is hoped that this is not wholly lost from the world, although the sense of earthly vanity inculcated by Christianity may have swallowed it up in humility.”
—Herman Melville (1819–1891)