A musical ratio of 48:25. Same as Diminished Eighth.

In classical music from Western culture, a **diminished octave** is an interval produced by narrowing a perfect octave by a chromatic semitone. 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 C4 to C5, and from C4 to C5 are **diminished octaves**, spanning eleven semitones. Being diminished, it is considered a dissonant interval.

The **diminished octave** is enharmonically equivalent to the major seventh. Wikipedia, Diminished Octave

See Also

**B Flat 3rd Octave**
**C 1st Octave**
**D 2nd Octave**
**Diminished**
**diminished seventh**
**E Sharp 3rd Octave**
**Figure 1.8 - Electromagnetic Scale in Octaves**
**Figure 11.01 - Octave composed of Equal Thirds and Triads**
**Figure 12.11 - Russells Locked Potential Full Ten Octave Gamut**
**Figure 12.12 - Russells Multiple Octave Waves as Fibonacci Spirals**
**Figure 12.12 - Russells Multiple Octave Waves as Fibonacci Spirals - See Also**
**Figure 17.03 - Analysis of the Octave Gravity Bar**
**Figure 7B.10 - Russells Periodic Chart of the first four octaves of proto-matter**
**Figure 9.16 - Russells 1-4 Octaves of Matter as Integrated Light - The Universal Constant**
**Figure 9.17 - Russells Ten Octaves of Matter as Integrated Light - The Universal Constant**
**Interval**
**Law of Octave**
**Octave**
**Major Seventh**
**Minor Seventh**
**Octave Relationships**
**RULE OF THE OCTAVE**
**Scale of the Forces in Octaves**
**Seventh**
**The Russell Nine Octave Chart of the Elements**
**11.15 - Indig Numbers - Inert Gases and Octave Position**
**12.17 - Note about Octave Relationships in Russells System**
**12.18 - Multiple Octave Progression**