Suomeksi | In English

Consonance and dissonance

Intervals are traditionally considered either consonant or dissonant. Consonant intervals are usually described as pleasant and agreeable. Dissonant intervals are those that cause tension and desire to be resolved to consonant intervals. These descriptions relate to harmonious intervals.

In music theory, consonances are traditionally divided into two groups: perfect and imperfect. Perfect intervals (1, 4, 5, 8) are perfect consonances, as seen in the polyphonic music of the Middle Ages. Imperfect consonances (3 and 6) are either major or minor.

Dissonances can be divided into sharp and soft dissonances. This division relates mainly to atonal music. Minor second and major seventh are sharp dissonances. In tonal music, non-diatonic intervals (diminished and augmented) are usually dissonances, but in jazz and other African-American music, the tritone is "neutral", in other words it does not require resolution to a consonance.

All the divisions mentioned above are based on a shared understanding of their meaning; in the course of history, there have been different views about the concord of simultaneous tones. These definitions mainly relate to individual intervals in notation. For example, an augmented second and a minor third are identical as sounds in equal temperament, but in the Western notation tradition, the former is considered a dissonance, the latter a consonance.

It should also be noted that the concepts "consonance" and "dissonance" are highly context-related. How sonance (consonance or dissonance) is perceived depends on several music-psychological factors: temperament (other than equal temperament is perceived as dissonance); genre (in atonal music, consonances are scarce); timbre; the extent of the interval (can be several octaves); harmonic environments before and after the interval; and so on.

Even an octave can appear dissonant (or more appropriately, "demanding resolution") in a sequence with an appoggiatura: