Consonance and dissonance
Concepts defining musical stability and tension through mutual exclusion.
Consonance and dissonance are categorizations of simultaneous or successive sounds in music. Within the Western tradition, some listeners associate consonance with sweetness, pleasantness, and acceptability, and dissonance with harshness, unpleasantness, or unacceptability, although this depends on familiarity and musical expertise. The terms form a structural dichotomy in which they define each other by mutual exclusion, though a finer consideration shows the distinction forms a gradation from the most consonant to the most dissonant.
- field
- Music theory, acoustics, psychoacoustics
- known_for
- Structural dichotomy in Western music; gradation from consonant to dissonant; role in polyphonic music and voice leading
- key_concept
- Definitions have varied for a thousand years and have never been completely explained
- related_term
- Sonance (encompasses both consonance and dissonance)
Lore & Background
The opposition between consonance and dissonance can be made in different contexts. In acoustics or psychophysiology, the distinction may be objective, based on perception of harmonic partials. In music, it is more often subjective, conventional, cultural, and style- or period-dependent. For example, a major second considered dissonant in a J.S. Bach prelude from the 1700s may sound consonant in a Claude Debussy piece from the early 1900s or an atonal contemporary piece. Most historical definitions since about the 16th century have stressed pleasant/unpleasant or agreeable/disagreeable character, though dissonances often play a decisive role in making music pleasant.
Reader's Guide
Consonance and dissonance are fundamental to Western polyphonic music, where they define points of rest and tension. Consonances include perfect intervals (unisons, octaves, perfect fourths and fifths) and imperfect consonances (major and minor thirds and sixths). Dissonances include major seconds, minor sevenths, tritones, minor seconds, and major sevenths. In a dissonant chord, one tone is deemed the dissonance requiring resolution through specific voice leading. Scientific definitions have been based on numerical ratios (simplicity of ratio), fusion (perception of unity), and coincidence of partials. Sensory dissonance relates to amplitude fluctuations: slow fluctuations produce beating, faster ones produce roughness, and very fast fluctuations disappear. The distinction between consonance and dissonance cannot match the psychophysiologic definition, as dissonances can make music pleasant even in a consonant context.
Did You Know?
- The terms form a structural dichotomy in which they define each other by mutual exclusion: a consonance is what is not dissonant, and a dissonance is what is not consonant.
- Paul Hindemith stressed that the two concepts have never been completely explained, and for a thousand years the definitions have varied.
- A major second (e.g., C and D played simultaneously) would be considered dissonant in a J.S. Bach prelude from the 1700s but may sound consonant in a Claude Debussy piece from the early 1900s.
- Sensory dissonance is related to amplitude fluctuations: slow fluctuations (≲20 per second) are perceived as beating, while faster ones (20–75 per second) are perceived as roughness.
Frequently Asked Questions
What are consonance and dissonance in music theory?
They are the two categories Western music theory uses to classify how simultaneous or successive sounds are perceived by a listener. Consonance is generally felt as stable and pleasant, while dissonance reads as tense or unstable, though a listener's familiarity and training heavily shape that judgment.
How do consonance and dissonance define each other?
They form a structural dichotomy in which each term gains its meaning only through the absence of the other. In practice, though, the boundary is a smooth spectrum rather than a hard line, so any given sonority sits somewhere on a continuum between the two poles.
Why hasn't a single definitive definition of consonance and dissonance emerged?
Scholars across music theory, acoustics, and psychoacoustics have proposed different explanations for roughly a thousand years without reaching full consensus. The concept sits at the intersection of physics, perception, and cultural habit, making a single universal definition elusive.
What role do consonance and dissonance play in composition?
They are the primary tools composers use to create and resolve tension in polyphonic writing and voice leading. By guiding voices between more stable and more unstable sonorities, a writer shapes the emotional arc of a passage.
How does the term 'sonance' relate to consonance and dissonance?
Sonance is an umbrella term that encompasses both consonant and dissonant combinations, treating them as points on a single spectrum rather than two separate categories. It is useful when a theorist wants to discuss a sonority without immediately labeling it stable or unstable.
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