music theory
Music theory is the study of theoretical frameworks for understanding the practices and possibilities of music. ''The Oxford Companion to Music'' describes three interrelated uses of the term "music theory": The first is the "Elements of music, ...
minor third
In music theory, a minor third is a interval (music), musical interval that encompasses three half steps, or semitones. Staff notation represents the minor third as encompassing three staff positions (see: interval (music)#Number, interval numb ...
s above the
root
In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...
. It is a minor triad with a lowered ( flattened) fifth. When using chord symbols, it may be indicated by the symbols "dim", "", "m5", or "MI(5)". However, in most popular-music chord books, the symbol "dim" or "" represents a diminished seventh chord (a four-tone chord), which in some modern jazz books and music theory books is represented by the "dim7" or "7" symbols.
For example, the diminished triad built on B, written as B, has pitches B-D-F:
:
The chord can be represented by the integer notation .
In the
common practice period
In Western classical music, the common practice period (CPP) was the period of about 250 years during which the tonal system was regarded as the only basis for composition. It began when composers' use of the tonal system had clearly supersede ...
In major scales, a diminished triad occurs only on the seventh
scale degree
In music theory, the scale degree is the position of a particular note on a scale relative to the tonic—the first and main note of the scale from which each octave is assumed to begin. Degrees are useful for indicating the size of intervals ...
. For instance, in the key of C, this is a B diminished triad (B, D, F). Since the triad is built on the seventh scale degree, it is also called the '' leading-tone triad''. This chord has a dominant function. Unlike the dominant triad or
dominant seventh
Domination or dominant may refer to:
Society
* World domination, structure where one dominant power governs the planet
* Colonialism in which one group (usually a nation) invades another region for material gain or to eliminate competition
* Ch ...
, the leading-tone triad functions as a prolongational chord rather than a structural chord since the strong root motion by fifth is absent.
On the other hand, in natural minor scales, the diminished triad occurs on the second scale degree; in the key of C minor, this is the D diminished triad (D, F, A). This triad is consequently called the ''
supertonic
In music, the supertonic is the second degree () of a diatonic scale, one whole step above the tonic. In the movable do solfège system, the supertonic note is sung as ''re''.
The triad built on the supertonic note is called the supertonic ...
diminished triad''. Like the supertonic minor triad found in a major key, the supertonic diminished triad has a predominant function, almost always resolving to a dominant functioning chord.
If the music is in a minor key, diminished triads can also be found on the raised seventh note, vii. This is because the ascending melodic minor scale has a raised sixth and seventh degree. For example, the chord progression vii–i is common.
The leading-tone diminished triad and supertonic diminished triad are usually found in first inversion (vii6 and ii6, respectively) since the spelling of the chord forms a diminished fifth with the bass. This differs from the fully diminished seventh chord, which commonly occurs in
root position
The root position of a chord (music), chord is the Voicing (music), voicing of a Triad (music), triad, seventh chord, or ninth chord in which the root (chord), root of the chord is the bass note and the other chord factors are above it. In the ro ...
. In both cases, the bass resolves up and the upper voices move downwards in contrary motion.
In popular music
Walter Everett writes that "In rock and pop music, the diminished triad nearly always appears on the second scale degree, forming a generally maudlin and dejected ii with its members, 2–4–6." Songs that feature ii include Santo & Johnny's " Sleep Walk", Jay and the Americans' " Cara Mia", and the Hollies' " The Air That I Breathe". Not so rare but rare enough so as to imply knowledge of and conscious avoidance on the part of rock musicians, examples of its use include
Oasis
In ecology, an oasis (; : oases ) is a fertile area of a desert or semi-desert environmentDon't Look Back in Anger",
David Bowie
David Robert Jones (8 January 194710 January 2016), known as David Bowie ( ), was an English singer, songwriter and actor. Regarded as one of the most influential musicians of the 20th century, Bowie was acclaimed by critics and musicians, pa ...
's " Space Oddity", and two in Daryl Hall's " Everytime You Go Away".
The vii in major keys is relatively less common than the ii, but still does happen. It is almost always used to tonicize the relative minor, in progressions such as vii–V7/vi–vi, which resembles ii–V7–i in the relative minor.
Tuning
In a twelve-tone equal temperament, a diminished triad has three semitones between the third and fifth, three semitones between the root and third, and six semitones between the root and fifth.
In 5-limit
just intonation
In music, just intonation or pure intonation is a musical tuning, tuning system in which the space between notes' frequency, frequencies (called interval (music), intervals) is a natural number, whole number ratio, ratio. Intervals spaced in thi ...
, the diminished chord on VII (in C: B–D–F) is 15:8, 9:8, and 4:3, while on II (in C: D–F–A) it is 9:8, 4:3, and 8:5 (135:160:192). According to Georg Andreas Sorge, the
trumpet
The trumpet is a brass instrument commonly used in classical and jazz musical ensemble, ensembles. The trumpet group ranges from the piccolo trumpet—with the highest Register (music), register in the brass family—to the bass trumpet, pitche ...
, in its overtone series on C, gives the diminished triad E–G–B = 5:6:7 ("perfect diminished chord"), but the 7 is too flat and 45:54:64 is preferred.Helmholtz describes the diminished triad as 1 − D , F, giving a just minor third and Pythagorean minor third (45:54:64) in the notation system used in '' On the Sensations of Tone as a Physiological Basis for the Theory of Music''.
Play , (5-limit major), or on C.
: