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:
“I was glad to have got out of the towns, where I am wont to feel unspeakably mean and disgraced,—to have left behind me for a season the bar-rooms of Massachusetts, where the full-grown are not weaned from savage and filthy habits,—still sucking a cigar. My spirits rose in proportion to the outward dreariness. The towns needed to be ventilated. The gods would be pleased to see some pure flames from their altars. They are not to be appeased with cigar-smoke.”
—Henry David Thoreau (1817–1862)
“He doesn’t know a damn thing about China ... That’s what makes him an expert. He knows nothing about music, being tone deaf. That’s what makes him a musician ... And he’s batty in the head. That’s what makes him a philosopher.”
—William Carlos Williams (1883–1963)