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:
“The bird would cease and be as other birds
But that he knows in singing not to sing.
The question that he frames in all but words
Is what to make of a diminished thing.”
—Robert Frost (1874–1963)
“Then, anger
was a crease in the brow
and silence
a catastrophe.
Then, making up
was a mutual smile
and a glance
a gift.
Now, just look at this mess
that you’ve made of that love.
You grovel at my feet
and I berate you
and can’t let my anger go.”
—Amaru (c. seventh century A.D.)