HarmonyIn music, harmony is the process by which individual sounds are joined or composed into whole units or compositions. More concretely, harmony often refers to the effects created by distinct musical pitches or tones coinciding with one another. These effects are variously identified, defined, and categorized as harmonic objects like chords, textures and tonalities. Harmony is broadly understood to involve both a "vertical" dimension (frequency-space) and a "horizontal" dimension (time-space), and often overlaps with related musical concepts such as melody, timbre, and form.
Chord (music)A chord, in music, is any harmonic set of pitches/frequencies consisting of multiple notes (also called "pitches") that are heard as if sounding simultaneously. For many practical and theoretical purposes, arpeggios and other types of broken chords (in which the chord tones are not sounded simultaneously) may also be considered as chords in the right musical context. In tonal Western classical music (music with a tonic key or "home key"), the most frequently encountered chords are triads, so called because they consist of three distinct notes: the root note, and intervals of a third and a fifth above the root note.
Quartal and quintal harmonyIn music, quartal harmony is the building of harmonic structures built from the intervals of the perfect fourth, the augmented fourth and the diminished fourth. For instance, a three-note quartal chord on C can be built by stacking perfect fourths, C–F–B. { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 1 } } Quintal harmony is harmonic structure preferring the perfect fifth, the augmented fifth and the diminished fifth.
Mystic chordIn music, the mystic chord or Prometheus chord is a six-note synthetic chord and its associated scale, or pitch collection; which loosely serves as the harmonic and melodic basis for some of the later pieces by Russian composer Alexander Scriabin. Scriabin, however, did not use the chord directly but rather derived material from its transpositions. When rooted in C, the mystic chord consists of the pitch classes: C, F, B, E, A, D. This is often interpreted as a quartal hexachord consisting of an augmented fourth, diminished fourth, augmented fourth, and two perfect fourths.
Chord progressionIn a musical composition, a chord progression or harmonic progression (informally chord changes, used as a plural) is a succession of chords. Chord progressions are the foundation of harmony in Western musical tradition from the common practice era of Classical music to the 21st century. Chord progressions are the foundation of popular music styles (e.g., pop music, rock music), traditional music, as well as genres such as blues and jazz. In these genres, chord progressions are the defining feature on which melody and rhythm are built.
