diminished major seventh
Component intervals from root
major seventh
diminished fifth (tritone)
minor third
root
Forte no. / Complement
4-18 / 8-18

In music theory, a diminished major seventh chord is a seventh chord composed of a diminished triad and a major seventh.[1] Thus, it is composed of a root note, together with a minor third, a diminished fifth, and a major seventh above the root: (1, 3, 5, 7). For example, the diminished major seventh chord built on C, commonly written as CoM7, has pitches C–E–G–B:


{
\override Score.TimeSignature #'stencil = ##f
\relative c' {
   \clef treble 
   \time 4/4
   \key c \major
   <c es ges b>1
} }

Diminished major seventh chords are very dissonant, containing the dissonant intervals of the tritone and the major seventh. They are frequently encountered, especially in jazz, as a diminished seventh chord with an appoggiatura, especially when the melody has the leading note of the given chord: the ability to resolve this dissonance smoothly to a diatonic triad with the same root allows it to be used as a temporary tension before tonic resolution. It is nevertheless infrequently used as a chord in itself.

The chord can be represented by the integer notation {0, 3, 6, 11}.

Diminished major seventh chord table

Chord Root Minor third Diminished fifth Major seventh
CoM7 C E G B
CoM7 C E G B (C)
DoM7 D F (E) A
double flat
(G)
C
DoM7 D F A C
DoM7 D F A C
double sharp
(D)
EoM7 E G B
double flat
(A)
D
EoM7 E G B D
FoM7 F A C (B) E
FoM7 F A C E (F)
GoM7 G B
double flat
(A)
D
double flat
(C)
F
GoM7 G B D F
GoM7 G B D F
double sharp
(G)
AoM7 A C (B) E
double flat
(D)
G
AoM7 A C E G
AoM7 A C E G
double sharp
(A)
BoM7 B D F (E) A
BoM7 B D F A

References

  1. ^ Jamini, Deborah. (2005). Harmony And Composition: Basics to Intermediate, p.204. ISBN 978-1-4120-3333-6.