Augmented sixthIn music, an augmented sixth () is an interval produced by widening a major sixth by a chromatic semitone. For instance, the interval from C to A is a major sixth, nine semitones wide, and both the intervals from C to A, and from C to A are augmented sixths, spanning ten semitones. Being augmented, it is considered a dissonant interval. Its inversion is the diminished third, and its enharmonic equivalent is the minor seventh. In septimal meantone temperament, it is specifically equivalent to the harmonic seventh (a just interval of 7:4).
Perfect fourthA fourth is a musical interval encompassing four staff positions in the music notation of Western culture, and a perfect fourth () is the fourth spanning five semitones (half steps, or half tones). For example, the ascending interval from C to the next F is a perfect fourth, because the note F is the fifth semitone above C, and there are four staff positions between C and F. Diminished and augmented fourths span the same number of staff positions, but consist of a different number of semitones (four and six, respectively).
Perfect fifthIn music theory, a perfect fifth is the musical interval corresponding to a pair of pitches with a frequency ratio of 3:2, or very nearly so. In classical music from Western culture, a fifth is the interval from the first to the last of the first five consecutive notes in a diatonic scale. The perfect fifth (often abbreviated P5) spans seven semitones, while the diminished fifth spans six and the augmented fifth spans eight semitones. For example, the interval from C to G is a perfect fifth, as the note G lies seven semitones above C.
Consecutive fifthsIn music, consecutive fifths or parallel fifths are progressions in which the interval of a perfect fifth is followed by a different perfect fifth between the same two musical parts (or voices): for example, from C to D in one part along with G to A in a higher part. Octave displacement is irrelevant to this aspect of musical grammar; for example, a parallel twelfth (i.e., an octave plus a fifth) is equivalent to a parallel fifth.
Dominant (music)In music, the dominant is the fifth scale degree () of the diatonic scale. It is called the dominant because it is second in importance to the first scale degree, the tonic. In the movable do solfège system, the dominant note is sung as "So(l)". The triad built on the dominant note is called the dominant chord. This chord is said to have dominant function, which means that it creates an instability that requires the tonic for resolution. Dominant triads, seventh chords, and ninth chords typically have dominant function.
UnisonIn music, unison is two or more musical parts that sound either the same pitch or pitches separated by intervals of one or more octaves, usually at the same time. Rhythmic unison is another term for homorhythm. Two pitches that are the same or two that move as one. Unison or perfect unison (also called a prime, or perfect prime) may refer to the (pseudo-)interval formed by a tone and its duplication (in German, Unisono, Einklang, or Prime), for example C–C, as differentiated from the second, C–D, etc.
OvertoneAn overtone is any resonant frequency above the fundamental frequency of a sound. (An overtone may or may not be a harmonic) In other words, overtones are all pitches higher than the lowest pitch within an individual sound; the fundamental is the lowest pitch. While the fundamental is usually heard most prominently, overtones are actually present in any pitch except a true sine wave. The relative volume or amplitude of various overtone partials is one of the key identifying features of timbre, or the individual characteristic of a sound.
Major thirdIn classical music, a third is a musical interval encompassing three staff positions (see Interval number for more details), and the major third () is a third spanning four semitones. Along with the minor third, the major third is one of two commonly occurring thirds. It is qualified as major because it is the larger of the two: the major third spans four semitones, the minor third three. For example, the interval from C to E is a major third, as the note E lies four semitones above C, and there are three staff positions from C to E.
Major chordIn music theory, a major chord is a chord that has a root, a major third, and a perfect fifth. When a chord comprises only these three notes, it is called a major triad. For example, the major triad built on C, called a C major triad, has pitches C–E–G: { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 \key c \major 1 } } In harmonic analysis and on lead sheets, a C major chord can be notated as C, CM, CΔ, or Cmaj. A major triad is represented by the integer notation {0, 4, 7}.
Dyad (music)In music, a dyad (less commonly, diad) is a set of two notes or pitches that, in particular contexts, may imply a chord. Dyads can be classified by the interval between the notes. For example, the interval between C and E is a major third, which can imply a C major chord, made up of the notes C, E and G. When the pitches of a dyad occur in succession, they form a melodic interval. When they occur simultaneously, they form a harmonic interval. The harmonic series is built over a fundamental pitch, and the rest of the partials in the series are called overtones.
