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<imagemap>
Image:Major and minor triads.png|400px|thumb|center|Major (<span style="color:red;">red</span>) and minor (<span style="color:blue;">blue</span>) triads on the white piano keys. <small>[[:File:Major and minor triads.png|<span style="color:#aaaaaa;">(file)</span>]]</small>

poly 35 442 35 544 179 493 [[A minor|root of A minor triad]]
poly 479 462 446 493 479 526 513 492 [[A minor|third of A minor triad]]
poly 841 472 782 493 840 514 821 494 [[A minor|fifth of A minor triad]]
poly 926 442 875 460 906 493 873 525 926 545 [[A minor|fifth of A minor triad]]
poly 417 442 417 544 468 525 437 493 469 459 [[C major|root of C major triad]]
poly 502 472 522 493 502 514 560 493 [[C major|root of C major triad]]
poly 863 462 830 493 863 525 895 493 [[C major|third of C major triad]]
poly 1303 442 1160 493 1304 544 [[C major|fifth of C major triad]]
poly 280 406 264 413 282 419 275 413 [[E minor|fifth of E minor triad]]
poly 308 397 293 403 301 412 294 423 309 428 [[E minor|fifth of E minor triad]]
poly 844 397 844 428 886 413 [[E minor|root of E minor triad]]
poly 1240 404 1230 412 1239 422 1250 412 [[E minor|third of E minor triad]]
poly 289 404 279 413 288 422 300 413 [[G major|third of G major triad]]
poly 689 398 646 413 689 429 [[G major|fifth of G major triad]]
poly 1221 397 1222 429 1237 423 1228 414 1237 403 [[G major|root of G major triad]]
poly 1249 406 1254 413 1249 418 1265 413 [[G major|root of G major triad]]
poly 89 567 73 573 90 579 86 573 [[D minor|fifth of D minor triad]]
poly 117 558 102 563 111 572 102 583 118 589 [[D minor|fifth of D minor triad]]
poly 650 558 650 589 693 573 [[D minor|root of D minor triad]]
poly 1050 563 1040 574 1050 582 1061 574 [[D minor|third of D minor triad]]
poly 98 565 88 573 98 583 110 574 [[F major|third of F major triad]]
poly 498 558 455 573 498 589 [[F major|fifth of F major triad]]
poly 1031 557 1031 589 1047 583 1038 574 1046 563 [[F major|root of F major triad]]
poly 1075 573 1059 580 1064 573 1058 567 [[F major|root of F major triad]]

desc none
</imagemap>


== See also ==
== See also ==

Revision as of 21:59, 10 October 2018

Types of triads: Iⓘ, iⓘ, ioⓘ, I+ⓘ

In music, a triad is a set of three notes (or "pitches") that can be stacked vertically in thirds.[1] The term "harmonic triad" was coined by Johannes Lippius in his Synopsis musicae novae (1612).

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

(Note: The notes of a triad do not have to use the root as the lowest note of the triad, due to the principle of inversion. A triad can also use the third or fifth as the lowest note of the triad. Inverting a triad does not change the root note.)

Some twentieth-century theorists, notably Howard Hanson[2] and Carlton Gamer,[3] expand the term to refer to any combination of three different pitches, regardless of the intervals amongst them. The word used by other theorists for this more general concept is "triad".[4] Others, notably Allen Forte, use the term to refer to combinations apparently stacked of other intervals, as in "quartal triad".[5]

In the late Renaissance music era, and especially during the Baroque music era (1600–1750), Western art music shifted from a more "horizontal" contrapuntal approach (in which multiple, independent melody lines were interwoven) toward progressions, which are sequences of triads. The progression approach, which was the foundation of the Baroque-era basso continuo accompaniment, required a more "vertical" approach, thus relying more heavily on the triad as the basic building block of functional harmony.

The root tone of a triad, together with the degree of the scale to which it corresponds, primarily determine a given triad's function. Secondarily, a triad's function is determined by its quality: major, minor, diminished or augmented. Major and minor triads are the most commonly used triad qualities in Western classical, popular and traditional music. In standard tonal music, only major and minor triads can be used as a tonic in a song or some other piece of music. That is, a song or other vocal or instrumental piece can be in the key of C major or A minor, but a song or some other piece cannot be in the key of B diminished or F augmented (although songs or other pieces might include these triads within the triad progression, typically in a temporary, passing role). Three of these four kinds of triads are found in the major (or diatonic) scale. In popular music and 18th-century classical music, major and minor triads are considered to be consonant and stable, and diminished and augmented triads are considered to be dissonant and unstable.[citation needed]

When we consider musical works we find that the triad is ever-present and that the interpolated dissonances have no other purpose than to effect the continuous variation of the triad.

— Lorenz Mizler (1739)[6]

Construction

Triads (or any other tertian triads) are built by superimposing every other note of a 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).

Function

Primary triads in C Playⓘ.

Each triad found in a diatonic (single-scale-based) key corresponds to a particular diatonic function. Functional harmony tends to rely heavily on the primary triads: triads built on the tonic, subdominant (typically the ii or IV triad), and dominant (typically the V triad) degrees.[7] The roots of these triads begin on the first, fourth, and fifth degrees (respectively) of the diatonic scale, otherwise symbolized: I, IV, and V (respectively). Primary triads, "express function clearly and unambiguously."[7] The other triads of the diatonic key include the supertonic, mediant, submediant, and subtonic, whose roots begin on the second, third, sixth, and seventh degrees (respectively) of the diatonic scale, otherwise symbolized: ii, iii, vi, and viio (respectively). They function as auxiliary or supportive triads to the primary triads.

See also

References

  1. ^ a b Ronald Pen, Introduction to Music (New York: McGraw-Hill, 1992): 81. 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. ^ Julien Rushton, "Triad", The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London: Macmillan Publishers, 2001).
  5. ^ Allen Forte, The Structure of Atonal Music (New Haven and London: Yale University Press, 1973): [page needed] ISBN 0-300-02120-8.
  6. ^ Allen Forte, Tonal Harmony in Concept and Practice, third edition (New York: Holt, Rinehart and Winston, 1979): 136. ISBN 0-03-020756-8.
  7. ^ a b Daniel Harrison, Harmonic Function in Chromatic Music: A Renewed Dualist Theory and an Account of its Precedents (Chicago: University of Chicago Press, 1994): 45. 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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