Diminished chord
From Wikipedia, the free encyclopedia
| Component intervals from root | ||
| diminished fifth | ||
| minor third | ||
| root | ||
Generally, in music, a diminished chord is a chord which has a diminished fifth in it. More specifically, it is a triad (a diminished triad) consisting of a minor third and diminished fifth above the root — if built on C, a diminished chord would have a C, an Eb and a Gb. The interval between the upper two notes is also a minor third — thus, the chord consists of two minor thirds stacked on top of one another. It resembles a minor triad with a lowered (or diminished) fifth.
In the common practice period, the diminished chord is considered dissonant, or unstable. It lacks tonal center or drive because the diminished fifth symmetrically divides the octave. Adding a further minor third on top of the chord (if built on C, this results in a chord consisting of C, Eb, Gb, and Bbb — the last of which, "B double-flat," may be enharmonically respelled as A) makes a fully diminished seventh chord (so called because C to Bbb is the interval of a diminished seventh). This chord is ambiguous as to root because a diminished seventh chord built from any note of it produces that same chord. This, combined with the fact that any of its notes may be enharmonically changed, makes it a useful pivot chord for modulation. Adding a major third rather than a minor third to the top (ex.: C/Eb/Gb/Bb) creates a half-diminished seventh chord (minor third, diminished fifth, minor seventh).
A diminished chord occurs in a major scale only on the seventh scale degree; in the key of C, this is BDF. This also occurs in the seventh chord built on the fifth note (that is, the dominant seventh); in C, this is GBDF. The diminished chord on the leading tone can thus function as a dominant seventh and resolve to the tonic chord. The diminished fifth is part of the strong sense of resolution possible in the progression from the dominant seventh to the tonic.
The diminished seventh chord comprises frequencies that are equally spaced when considered on a logarithmic axis, and thus divides the octave into four logarithmically equal portions.
In a twelve-tone equal tempered tuning, a diminished chord has 3 semitones between the third and fifth, 3 between the root and third, and 6 between the root and fifth. It is represented by the integer notation 0,3,6.
The fundamental tone or root of any diminished seventh chord, being composed of three stacked minor thirds, is ambiguous. For example, Cdim7 in root position: C + E♭ + G♭ + B♭♭, is just as easily viewed as an E♭dim7 in its first inversion:
- D♭♭ (enharmonic equivalent of C) + E♭ + G♭ + B♭♭.
It can also be viewed as a G♭dim7 in its second inversion:
- D♭♭ + F♭♭ (enharmonic equivalent of E♭) + G♭ + B♭♭.
Delineating this chord in its last possibility, that of B♭♭dim7 in its third inversion, is very clumsy and not very useful as it requires the use a triple-flatted note, something that is never used in a musical score:
- A♭♭♭ (enharmonic equivalent of G♭) + B♭♭ + D♭♭ + F♭♭.
The point that should not be lost in this morass of musical notation is that by any of its four possible names, this chord is played and sounds exactly the same. What makes the chord so unusual is the number of ways it can be harmonically resolved and only after it is resolved does the chord reveal its true identity.
[edit] See also
|
|
||
|---|---|---|
|
|
||
| By Type | Triad | Major · Minor · Augmented · Diminished · Suspended |
|
|
||
| Seventh | Major · Minor · Dominant · Diminished · Half-diminished · Minor-major · Augmented major · Augmented minor | |
|
|
||
| Extended | Ninth · Eleventh · Thirteenth | |
|
|
||
| Other | Sixth · Augmented sixth · Altered · Added tone · Polychord · Quartal and quintal · Tone cluster · Power | |
|
|
||
| By Function | Diatonic | Tonic · Dominant · Subdominant · Submediant |
|
|
||
| Altered | Borrowed · Neapolitan chord · Secondary dominant | |
|
|
||
| With Names | Elektra chord · Hendrix chord · Mystic chord · Petrushka chord · Tristan chord · So What chord | |
