Triad (music)

Source: Wikipedia, the free encyclopedia.
Types of triads: Iⓘ, iⓘ, ioⓘ, I+ⓘ

In music, a triad is a set of three notes (or "pitch classes") that can be stacked vertically in thirds.[1] Triads are the most common chords in Western music.

When stacked in thirds, notes produce triads. The triad's members, from lowest-pitched tone to highest, are called:[1]

  • the root
    • Note: Inversion does not change the root. (The third or fifth can be the lowest note.)
  • the third – its interval above the root being a minor third (three semitones) or a major third (four semitones)
  • the fifth – its interval above the third being a minor third or a major third, hence its interval above the root being a
    traditional music
    .

Some 20th-century theorists, notably Howard Hanson,[2] Carlton Gamer,[3] and Joseph Schillinger[4] expand the term to refer to any combination of three different pitches, regardless of the intervals. Schillinger defined triads as "A structure in harmony of but three parts; conventionally, but not necessarily, the familiar triad of ordinary diatonic harmony." The word used by other theorists for this more general concept is "trichord".[5] Others use the term to refer to combinations apparently stacked by other intervals, as in "quartal triad"; a combination stacked in thirds is then called a "tertian triad".

The root of a triad, together with the degree of the scale to which it corresponds, primarily determine its function. Secondarily, a triad's function is determined by its quality:

dissonant and unstable.[citation needed
]

When we consider musical works we find that the triad is ever-present and that the interpolated

Lorenz Mizler (1739)[6]

History

In the late

functional harmony
.

The primacy of the triad in Western music was first theorized by Gioseffo Zarlino (1500s), and the term "harmonic triad" was coined by Johannes Lippius in his Synopsis musicae novae (1612).

Construction

Triads (or any other

diatonic scale
(e.g., standard major or minor scale). For example, a C major triad uses the notes C–E–G. This spells a triad by skipping over D and F. While the interval from each note to the one above it is a third, the quality of those thirds varies depending on the quality of the triad:

  • major triads contain a major third and perfect fifth interval, symbolized: R 3 5 (or 0–4–7 as semitones) playⓘ
  • minor triads contain a minor third, and perfect fifth, symbolized: R ♭3 5 (or 0–3–7) playⓘ
  • diminished triads contain a minor third, and diminished fifth, symbolized: R ♭3 ♭5 (or 0–3–6) playⓘ
  • augmented triads contain a major third, and augmented fifth, symbolized: R 3 ♯5 (or 0–4–8) playⓘ

The above definitions spell out the interval of each note above the root. Since triads are constructed of stacked thirds, they can be alternatively defined as follows:

  • major triads contain a major third with a minor third stacked above it, e.g., in the major triad C–E–G (C major), the interval C–E is major third and E–G is a minor third.
  • minor triads contain a minor third with a major third stacked above it, e.g., in the minor triad A–C–E (A minor), A–C is a minor third and C–E is a major third.
  • diminished triads contain two minor thirds stacked, e.g., B–D–F (B diminished)
  • augmented triads contain two major thirds stacked, e.g., D–F♯–A♯ (D augmented).

Triads appear in close or open positions. "When the three upper voices are as close together as possible, the spacing is described as close position or close harmony. [...] The other arrangements [...] are called open position or open harmony."[7]

Function

Primary triads in C playⓘ

Each triad found in a diatonic (single-scale-based) key corresponds to a particular

function clearly and unambiguously."[8] The other triads in diatonic keys include the supertonic, mediant, submediant, and subtonic
, whose roots are the second, third, sixth, and seventh degrees (respectively) of the diatonic scale, symbolized ii, iii, vi, and viio. They function as auxiliary or supportive triads to the primary triads.

See also

  • Upper structure triad

References

  1. ^
    ISBN 0-07-038068-6
    . "A triad is a set of notes consisting of three notes built on successive intervals of a third. A triad can be constructed upon any note by adding alternating notes drawn from the scale. ... In each case the note that forms the foundation pitch is called the root, the middle tone of the triad is designated the third (because it is separated by the interval of a third from the root), and the top tone is referred to as the fifth (because it is a fifth away from the root)."
  2. ^ Howard Hanson, Harmonic Materials of Modern Music: Resources of the Tempered Scale (New York: Appleton-Century-Crofts, 1960).
  3. ^ Carlton Gamer, "Some Combinational Resources of Equal-Tempered Systems", Journal of Music Theory 11, no. 1 (1967): 37, 46, 50–52.
  4. ^ Joseph Schillinger, The Schillinger System of Musical Composition (New York: Carl Fischer,1941).
  5. ^ Julien Rushton, "Triad", The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London: Macmillan Publishers, 2001).
  6. ISBN 0-03-020756-8
    .
  7. ^ W. Apel, Harvard Dictionary of Music (Cambridge, Mass., Harvard University Press, 1950): 704, s.v. Spacing.
  8. ^
    ISBN 0-226-31808-7
    . Cited on p. 274 of Deborah Rifkin, "A Theory of Motives for Prokofiev's Music", Music Theory Spectrum 26, no. 2 (2004): 265–289.
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