Augmented seventh Adding a diesis to this makes up an octave. Hence, this interval's complement, the diminished second, is often referred to as a diesis. Augmented seventh In classical music from Western culture, an augmented seventh is an interval produced by widening a major seventh by a chromatic semitone. For instance, the interval from C to B is a major seventh, eleven semitones wide, and both the intervals from C to B, and from C to B are augmented sevenths, spanning twelve semitones. Being augmented, it is classified as a dissonant interval. However, it is enharmonically equivalent to the perfect octave. Since
Seventh octave but some people who are capable of singing in the bass range (like singers Adam Lopez or Nicola Sedda) can do it. While notes in the sixth octave, between soprano high C and C7, can have enough color to sound flutey or canary-like, the squeaky, whistly tones in the seventh octave help give the whistle register its name, as do the piercing qualities of notes in this octave. Seventh octave The seventh octave is the highest octave of a piano. Using middle C (C4) as a guide, the next higher C is C5 or tenor C. The next C is