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:
“Human life itself may be almost pure chaos, but the work of the artist—the only thing he’s good for—is to take these handfuls of confusion and disparate things, things that seem to be irreconcilable, and put them together in a frame to give them some kind of shape and meaning. Even if it’s only his view of a meaning. That’s what he’s for—to give his view of life.”
—Katherine Anne Porter (1890–1980)
“Our medieval historians who prefer to rely as much as possible on official documents because the chronicles are unreliable, fall thereby into an occasionally dangerous error. The documents tell us little about the difference in tone which separates us from those times; they let us forget the fervent pathos of medieval life.”
—Johan Huizinga (1872–1945)