Roughness (psychophysics)
Encyclopedia
The perceived roughness of a sound is simply how rough it sounds. In an experiment to measure and compare the roughness of different sounds, listeners are presented with different sounds and asked to rate their roughness, for example on a rating scale
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According to psychophysical theory, the roughness of a complex sound (a sound comprising many partials or pure tone
components) depends on the distance between the partials measured in critical bandwidths. Any simultaneous pair of partials of about the same amplitude that is less than a critical bandwidth apart produces roughness associated with the inability of the basilar membrane
to separate them clearly.
Roughness is physiologically determined and therefore universal, but it is appraised differently in different musical styles. Some musical styles deliberately create large amounts of roughness for aesthetic effect (for example some polyphonic styles in the Balkans in which singers favor simultaneous second intervals) while others try to avoid roughness as music as possible or treat rough sounds in special ways (for example most tonal western music).
Rating scale
A rating scale is a set of categories designed to elicit information about a quantitative or a qualitative attribute. In the social sciences, common examples are the Likert scale and 1-10 rating scales in which a person selects the number which is considered to reflect the perceived quality of a...
.
According to psychophysical theory, the roughness of a complex sound (a sound comprising many partials or pure tone
Pure tone
A pure tone is a tone with a sinusoidal waveshape.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...
components) depends on the distance between the partials measured in critical bandwidths. Any simultaneous pair of partials of about the same amplitude that is less than a critical bandwidth apart produces roughness associated with the inability of the basilar membrane
Basilar membrane
The basilar membrane within the cochlea of the inner ear is a stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani .-Function:...
to separate them clearly.
Roughness is physiologically determined and therefore universal, but it is appraised differently in different musical styles. Some musical styles deliberately create large amounts of roughness for aesthetic effect (for example some polyphonic styles in the Balkans in which singers favor simultaneous second intervals) while others try to avoid roughness as music as possible or treat rough sounds in special ways (for example most tonal western music).
See also
- Auditory maskingAuditory maskingAuditory masking occurs when the perception of one sound is affected by the presence of another sound.- Simultaneous masking :Simultaneous masking is when a sound is made inaudible by a "masker", a noise or unwanted sound of the same duration as the original sound.-Critical bandwidth:If two sounds...
- Consonance and dissonanceConsonance and dissonanceIn music, a consonance is a harmony, chord, or interval considered stable, as opposed to a dissonance , which is considered to be unstable...
- PsychoacousticsPsychoacousticsPsychoacoustics is the scientific study of sound perception. More specifically, it is the branch of science studying the psychological and physiological responses associated with sound...
(Masking effects)
Sources
- Plomp, R. & Levelt, W.J.M. (1965). Tonal consonance and critical bandwidth. Journal of the Acoustical Society of AmericaAcoustical Society of AmericaThe Acoustical Society of America is an international scientific society dedicated to increasing and diffusing the knowledge of acoustics and its practical applications.-History:...
, Vol. 38, pp. 548–560. - Terhardt, E. (1974). On the perception of periodic sound fluctuations (roughness). Acustica.