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Diatonic intervals
semitone / whole tone
Special intervals
Ditone Tritone
Natural septime

A fourth or quart (from Latin quarta 'the fourth', ancient Greek diatessaron [ διά dia + τεσσάρων tessaron ] 'every fourth' or 'all four') is an interval in music that spans four notes of a diatonic , heptatonic scale .

Example : scale section from g 'to c' '(4 pitches) - fourth g' c '' one after the other - fourth g 'c' 'at the same time.

X: 2019/10 M: 4/4 L: 1/4 K: C GAB c |  z2 G c |  z2 [G2c2] |]

As a “pure” fourth it comprises five, and in its “impure” variants also four or six semitone steps. The complementary interval to the fourth is the fifth .

In a narrower sense, the fourth also means the fourth degree of a scale. If not the interval, but the tone level is meant, the clearer term quartton can be used.


\ relative c {\ override Staff.TimeSignature # 'stencil = ## f \ key c \ major \ time 5/2 \ clef "treble" s4 ^ "a) pure" g''1 c s4 \ bar "||"  s ^ "b) excessive" g1 cis s4 \ bar "||"  s ^ "c) decreased" gis1 c s4 \ bar "||"  }

The fourth can appear in three variants:

  • The pure fourth (a), in which the frequencies behave like 4: 3 in natural tuning , is the most common. It is used frequently in all types of music and, like the fifth, is often used as a signal-like sequence of tones , such as with the German siren or as a flourish at carnival. Depending on the musical context, the pure fourth is treated as a dissonance or a consonance :
    • In the two-part contrapuntal movement ( bicinium ) the fourth is considered a dissonance.
    • In a polyphonic sentence
      • fourths above the bass note (so-called primary fourths ) are also considered dissonant in certain contexts, e.g. B. in the sixth fourth chord .
      • fourths between two upper voices (so-called secondary fourths ) are considered consonant, e.g. B. the interval  g-c ' in the chord  c-eg-c' .
  • The excessive fourth (b), also known as the tritone , results u. a. between the 4th level and the leading tone (upwards) of a major scale ( e.g. C major: F – B ). This interval, which is considered dissonant, has long been a problem with the sound system (“diabolus in musica”) and was still considered unusable after the Middle Ages. The excessive fourth is the characteristic interval of the Lydian scale , hence it is also called the Lydian fourth .
  • The diminished fourth (c) may come. a. between the 3rd step and the leading tone (downwards) of a minor scale ( e.g. a minor: c'- g sharp ).
interval Semitones example Reversal interval
(b) excessive fourth ( tritone ) 6 (3 whole tones) C-F sharp , FH , Eb-A
"Ma ri a" (Leonard Bernstein, West Side Story )
diminished fifth
(a) pure fourth 5 (2 whole tones + 1 semitone) CF , EA
" The win is passed ter " (Up)
"on, you young he wanderer" (down and up)
Mozart's Eine kleine Nachtmusik (down and up)
perfect fifth
(c) diminished fourth 4 (1 whole step + 2 semitones) C-Fes , C-G sharp
"Prepare yourself, Zi on " (JS Bach, Christmas Oratorio )
excessive fifth

Double meaning of the expression "pure fourth"

The term "pure" fourth is used on the one hand to mean "neither diminished nor excessive", on the other hand also for the frequency ratio of exactly 4: 3, as it belongs to the pure tuning .

Audio samples

See also

Web links

Commons : Perfect fourths  - collection of images, videos and audio files

Individual evidence

  1. Johann Gottfried Walther : Musical Lexicon [...]. Wolffgang Deer, Leipzig 1732, p. 508 ( Quarta falsa )
  2. Marc Honegger, Günther Massenkeil (ed.): The great lexicon of music. Volume 6, Herder, Freiburg im Breisgau a. a. 1987, ISBN 3-451-22921-8 , p. 374.
  3. Music lexicon in four volumes. Third volume. 2nd edition, Metzler, Stuttgart 2005, ISBN 978-3-476-02086-4 , p. 774.
  4. ^ Walter Opp: Handbuch Kirchenmusik , Volume 1, Merseburger 2001, pages 216, 225, 235. ISBN 3-87537-281-6