Seventh chord

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A seventh chord , also a seventh chord, is a four-note chord . To the triad consisting of the root , third and fifth steps of the respective diatonic scale, the seventh step is added as an extension by a further third interval. Seventh chords are considered dissonant and in need of resolution in traditional harmony . It was not until the late 19th century (approx. The last third of the epoch) that the seventh chord gradually developed into a chord type that no longer necessarily required a resolution. The seventh chord in all its forms plays a central role in jazz harmonic and replaces the triad as a harmonic "basic material".

Dominant seventh dip in the form of passages and Provision the first time around in 1600, so in the late Renaissance music on. As chords with their own harmonic function, they can only be found in high baroque composers .

Formation and types of seventh chords

The abovementioned terms root, third, fifth and seventh are the pitches of the underlying diatonic scale. The seventh chords can also be described as a "layering" of three third intervals on top of one another; the types of seventh chords then differ in the use of minor and major thirds. The following table lists the names of the various seventh chords, which triads they are based on, which seventh is added, how they are formed from the note c, how they are notated as chord symbols and at which levels of the following scales they occur: major, natural / Aeolian minor , harmonic minor , melodic minor upwards (downwards the melodic minor is identical to the natural minor):

Surname Triad + Seventh example Chord symbol
(jazz harmonic) 		major nat. minor harm. minor mel. Minor
upwards
Dominant seventh chord major small c – e – g – b C 7 V VII V IV, V
Great seventh chord major big c – e – g – h C maj7 , C Δ , C 7+ I, IV III, VI VI -
Minor seventh chord minor small c – es – g – b Cm 7 II, III, VI I, IV, V IV II
Minor seventh chord with a major seventh minor big c – es – g – h Cm maj7 , Cm Δ , Cm 7+ - - I. I.
Half diminished seventh chord reduced small c – es – ges – b Cm Ø , Cm 5- / 7 VII II II VI, VII
Diminished seventh chord * reduced reduced c – es – ges – heses C °, C 07 , C v7 - - VII -
Excessive seventh chord excessively big c – e – gis – h C 5 + / maj7 , C 5 + / 7 + - - III III

* also: "Completely diminished seventh chord" or "Completely diminished seventh chord"

Inversions of 7th chords

Inversions of 7th chords

Seventh chords can appear in the basic position (with three thirds) and in three inversions (with two thirds and one second):

  • Basic position - seventh chord
  • 1st inversion - sixth fifth chord
  • 2nd inversion - third quarto chord
  • 3. Inversion - Secondary Chord

The chord names come from the figured bass and are derived from its interval layering over the lowest chord tone.

Dominant seventh chords

Dominant seventh chord

function

The dominant seventh chord is mostly, but not always, heard and interpreted as a dominant . In rare exceptional cases, he may appear in a different function, e.g. B. (as a ladder's own chord) on the fourth level of the upward-leading melodic minor scale in a subdominant function.

Example of the resolution of a dominant seventh chord (in third quart form) into a tonic
Example of both resolutions of a dominant seventh chord in a four-part setting,
pure tuning

equal mood

resolution

In the dissolution of the dominant seventh chord, two tones have a clear tendency: The third tone of the dominant seventh chord is also the leading tone (VII. Degree of the scale) and is resolved in ascending order (small second / semitone) into the root of the I degree (tonic); the seventh tone of the dominant seventh chord falls as a sliding tone (in major by a minor second, in minor by a major second) in the third of the tonic.

If in the four-part movement the fundamental in the bass moves up a fourth or down a fifth to that of the tonic, only the fifth remains . This usually falls to the root of the tonic or it rises to the third of the tonic. Thus, the resolution of a complete dominant seventh chord in a four-part movement results in an incomplete tonic triad in which the fifth is missing: the root is either tripled or the root and third are doubled.

In a so-called incomplete dominant seventh chord, the root note is doubled and the least characteristic note, the fifth note, is missing. (The third tone is decisive for the major-minor characteristic, the seventh tone makes the chord a seventh chord. The absence of the perfect fifth, however, is hardly noticeable to the ear). In the four-part movement, this chord dissolves into a complete triad with doubling of the root note.

Shortened dominant seventh chord

In the shortened dominant seventh chord, the root note is omitted. Instead of a seventh chord, a diminished triad of the seventh degree sounds. However, its lead tone voltage makes it appear in a dominant function.

In the strict four-part set it is almost always used as a sixth chord , i.e. H. the third or fifth tone is in the bass and is doubled. Doubling the seventh tone is forbidden, because then the correct handling of the sentence would lead to a prime or octave parallel .

Half diminished seventh chord

The half diminished seventh chord occurs in major in the seventh degree and in (natural and harmonic) minor in the II degree. It also appears on the upward-going melodic minor scale on VI. and VII. stage.

  • In the major, it is seen by functional theory as a dominant seventh chord of the fifth degree that has been shortened by its root note , and as such has a dominant function.
  • The half diminished seventh chord on the second degree of the natural and harmonic minor has a subdominant function, as its tone supply - albeit in a different order - corresponds to the sixth ajoutée chord on the subdominant . As part of the II-VI connection in minor, it can often be found in jazz .
  • With the melodic minor (upwards) there is the somewhat paradoxical situation that the seventh chord on the VI. Level is structurally a dominant seventh chord shortened by its root, but its function is that of a subdominant because of the fourth level as the root of the complete chord. On the other hand, the functional interpretation of the seventh chord on the seventh degree as a shortened dominant-non-chord, which here - in contrast to before - actually appears in a dominant function is unproblematic.

Diminished seventh chord

The diminished seventh chord consists of a diminished triad with a diminished seventh. This chord can also be understood as a dominant seventh chord shortened by its root and therefore has a dominant function. It occurs as a ladder's own chord on the VIIth level of the harmonic minor scale.

In the sense of 12-tone music, where no distinction is made between diatonic and chromatic semitones, it is an isointerval chord , in which all occurring intervals consist of three semitones.

Dissolution of the diminished seventh chord

Voice leading in the resolution of the diminished seventh chord on the VII degree of A minor

In the diminished seventh chord there are strong tensions due to the nature of the interval. The frame interval (diminished seventh) tends inward with both tones, as do the two diminished fifths. This results in a resolution that takes into account all intertension in its voice guidance, the doubling of the third tone of the target triad.

Ambiguity of the diminished seventh chord

Rheinberger describes the diminished seventh chord as the "chameleon of harmony". It is absolutely symmetrical in itself and its inversions cannot be distinguished from its basic position with equal tuning in terms of structure and sound. (In the score, minor thirds change to excessive seconds when reversed.) This means that each of its tones can be interpreted as a leading tone (if necessary after a corresponding enharmonic mix-up ) , so that there are 4 different possible ways of resolving this chord. Example:

|aaa
equal mood:
      pure mood

Characteristic examples of the occurrence of the diminished seventh chord in the 18th and early 19th centuries: “Barrabam!” In Bach's St. Matthew Passion , appearance of the Commander in the second finale of Mozart's Don Giovanni , Samiel motif in Weber's Freischütz .

In Impressionism it (like many chords) loses its functional harmonic meaning and is often used as a timbre chord or for chromatic shifts (parallel guides). In isolated cases, however, chromatic indentations of the diminished seventh chord were used much earlier (e.g. in Bach's Chromatic Fantasie BWV 903).

Sound symbolism

The originally important symbolic meaning of the four chords (e.g. the diminished seventh chord as an expression of the terrible, diabolical, demonic), which was originally (e.g. in the Baroque ), was increasingly forgotten due to frequent use and has almost been lost since the late Romantic period .

literature

  • Jean-Philippe Rameau : Nouveau Système de musique théorique . Paris 1726
  • Jean-Baptiste le Rond d'Alembert : Systematic introduction to musical typesetting according to the tenets of Mr. Rameau . Translated from the French and supplemented with notes by Friedr. Wilh. Marpurg. Leipzig 1757

Web links

Remarks

  1. ↑ Assignment: harmonic D flat minor (with eight ♭). In harmony in C minor, the seventh chord on the seventh degree is hdf-a-flat
  2. ↑ By the difference note C of the pure third c'e ' the bass C of the tonic is amplified in pure tuning, as you can hear. In equal tuning, the difference tone corresponds to the tone C sharp . It does not reinforce c .
  3. ↑ The occurring intervals are:
    pure minor third (frequency ratio 6/5 corresponds to 316 cents)
    Pythagorean minor third (frequency ratio 32/27 corresponds to 294 cents, one third point lower)
    excessive second (frequency ratio 75/64 corresponds to 274 cents, one third point lower)

Individual evidence

  1. ↑ D. de la Motte: Harmony. Bärenreiter Verlag, 3rd edition 1980, ISBN 3-7618-0540-3 , page 54 f.
  2. ↑ Reinhard Amon: Lexicon Harmony . ISBN 3-900695-70-9 , p. 323