diminished octave

{{Infobox Interval|

main_interval_name = diminished octave|

inverse = Augmented unison|

complement = Augmented unison|

other_names = Diminished eighth|

abbreviation = d8|

semitones = 11|

interval_class = 1|

just_interval = 48:25, 49:26 (13-limit), 256:135, 4096:2187|

cents_equal_temperament = 1100{{cite book|last1=Duffin|first1=Ross W.|title=How equal temperament ruined harmony : (and why you should care)|date=2008|publisher=W. W. Norton|location=New York|isbn=978-0-393-33420-3|page=163|edition=First published as a Norton paperback.|url=https://books.google.com/books?id=i5LC7Csnw7UC&q=how+equal+temperament+ruined+harmony|access-date=28 June 2017|language=en}}|

cents_24T_equal_temperament = |

cents_just_intonation = 1129, 1108, 1086

}}

Image:Diminished octave on C.png

Image:Diminished octave on C-sharp.png

In music from Western culture, a diminished octave ({{Audio|Major seventh on C.mid|Play}}) is an interval produced by narrowing a perfect octave by a chromatic semitone.Benward & Saker (2003). Music: In Theory and Practice, Vol. I, p.54. {{ISBN|978-0-07-294262-0}}. Specific example of an d8 not given but general example of perfect intervals described. As such, the two notes are denoted by the same letter but have different accidentals. For instance, the interval from C₄ to C₅ is a perfect octave, twelve semitones wide, and both the intervals from C{{Music|sharp}}₄ to C₅ and from C₄ to C{{Music|b}}₅ are diminished octaves, spanning eleven semitones. Being diminished, it is considered a dissonant interval.Benward & Saker (2003), p.92.

The diminished octave is enharmonically equivalent to the major seventh.