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:
“Some have asked if the stock of men could not be improved,—if they could not be bred as cattle. Let Love be purified, and all the rest will follow. A pure love is thus, indeed, the panacea for all the ills of the world.”
—Henry David Thoreau (1817–1862)
“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)