In classical music from Western culture, a diminished seventh ( play) is an interval produced by narrowing a minor seventh by a chromatic semitone. For instance, the interval from A to G is a minor seventh, ten semitones wide, and both the intervals from A♯ to G, and from A to G♭ are diminished sevenths, spanning nine semitones. Being diminished, it is considered a dissonant interval.
The diminished seventh is enharmonically equivalent to a major sixth. Its inversion is the augmented second.
The diminished seventh is used quite readily in the minor key, where it is present in the harmonic minor scale between the seventh scale step and the sixth scale step in the octave above.
In an equal tempered tuning, a diminished seventh is equal to nine semitones, a ratio of 29/12:1 (approximately 1.682), or 900 cents. There is no standard just tuning of this interval, but one possibility, assuming the flat submediant is a perfect (5:4) major third below the octave, and the leading tone to be 15:16, would lead to an interval of 128:75, about 925 cents; another interval is 216:125, which is three minor thirds.
The 128:75 just diminished seventh arises in the C harmonic minor scale between B and A♭ by combining B-D, D|F, F-A♭. Play
Famous quotes containing the words diminished and/or seventh:
“Obscurantism is the academic theorist’s revenge on society for having consigned him or her to relative obscurity—a way of proclaiming one’s superiority in the face of one’s diminished influence.”
—David Lehman (b. 1948)
“When my face turned toward his,
I averted it
and looked at my feet.
When my ears clamored
to hear his talk,
I stopped them.
When my cheeks broke out
in sweat and goosebumps,
I covered them with my hands.
But Friends,
when the seams of my bodice
burst in a hundred places,
what could I do?”
—Amaru (c. seventh century A.D.)