In music, a consonance (Latin con-, "with" + sonare, "to sound") is a harmony, chord, or interval considered stable (at rest), as opposed to a dissonance (Latin dis-, "apart" + sonare, "to sound"), which is considered unstable (or temporary, transitional). In more general usage, a consonance is a combination of notes that sound pleasant to most people when played at the same time; dissonance is a combination of notes that sound harsh or unpleasant to most people.

The definition of consonance has been variously based on experience, frequency, and both physical and psychological considerations. These include:

Blend/fusion: perception of unity or tonal fusion between two notes (Stumpf)

Frequency ratios: with ratios of lower simple numbers being more consonant than those that are higher (Pythagoras). Many of these definitions do not require exact integer tunings, only approximation.

Coincidence of partials: with consonance being a greater coincidence of partials (called harmonics or overtones when occurring in harmonic timbres) (Helmholtz, 1877/1954). By this definition, consonance is dependent not only on the width of the interval between two notes (i.e., the musical tuning), but also on the combined spectral distribution and thus sound quality (i.e., the timbre) of the notes (see the entry under critical band). Thus, a note and the note one octave higher are highly consonant because the partials of the higher note are also partials of the lower note. Although Helmholtz's work focused almost exclusively on harmonic timbres and tunings, subsequent work has generalized his findings to embrace non-harmonic tunings and timbres.

Fusion or pattern matching: fundamentals may be perceived through pattern matching of the separately analyzed partials to a best-fit exact-harmonic template (Gerson & Goldstein, 1978) or the best-fit subharmonic (Terhardt, 1974). Harmonics may be perceptually fused into one entity — consonances being those that include:

Perfect consonances:
unisons and octaves
perfect fourthsa and perfect fifths
Imperfect consonances:
major thirds and minor sixths
minor thirds and major sixths
"Continuity: consonances are continuous and dissonances are intermittent in sensation, determined by coincidence of partials." (Helmholtz) Wikipedia, Consonance and Dissonance

The key-note C sounding from within itself its six tones to and fro in trinities, the tones written as notes in musical clef
—The trinities hereafter termed primaries and secondaries
—The seven of each of the twelve key notes developing their tones
—The order in which the tones meet, avoiding consecutive fifths
Dissonance is not opposition or separation
—The use of the chasms and double tones is seen
—The isolated fourths sound the twelve notes
—Each double tone developes only one perfect major harmony, with the exception of F#-G♭; F# as the key-tone sounds F♮ as E#, and G♭ as the key-tone sounds B♮ as C♭
—The primaries of the twelve key-notes are shown to sound the same tones as the secondaries of each third harmony below, but in a different order
—All harmonies are linked into each other, . 23 [Harmonies of Tones and Colours, Table of Contents2 - Harmonies]

combinations of dissonance, rests, sounding neither scale nor chords. Dissonance does not express opposition or separation, for there is no principle in musical tones which is productive of contraries; the dissonances follow the attraction of the tonic, or key-note, and the neutralization of the musical disturbance is implied in the disagreement in their motion with the repose of the unit, or key-note. So far is this from producing separation, that the apparent discord is simply a preparation for growth, the life of harmony causing an inherent tendency towards closer union. [Harmonies of Tones and Colours, Combinations of dissonance, rests, page 24]

See Also

06 - Chart Showing the Conditions Governing the Discordants
13.12.1 - Disturbance of Equilibrium
13.23 - Degree of Concord Discord Determines
8.24 - The Dance of Concord and Discord
discordant aggregation
Figure 8.7 - Varying Degrees of Chordal Harmony and Discord
negative discordant
Part 23 - Harmony is Health - Discord is Disease

Created by Dale Pond. Last Modification: Sunday March 14, 2021 05:18:55 MDT by Dale Pond.