Diminished sixth
In classical music from Western culture, a diminished sixth is an interval produced by narrowing a minor sixth by a chromatic semitone. For example, the interval from A to F is a minor sixth, eight semitones wide, and both the intervals from A to F, and from A to F are diminished sixths, spanning seven semitones. Being diminished, it is considered a dissonant interval, despite being equivalent to an interval known for its consonance.
Its inversion is the augmented third, and its enharmonic equivalent is the perfect fifth.A severely dissonant diminished sixth is observed when the instrument is tuned using a Pythagorean or a meantone temperament tuning system. Typically, this is the interval between G and E. Since it seems to howl like a wolf, and since it is meant to be the enharmonic equivalent to a fifth, this interval is called the wolf fifth. Notice that a justly tuned fifth is the most consonant interval after the perfect unison and the perfect octave.
