User:Sonia/Augmented seventh
 | This article does not have any sources. (December 2009) |
| Inverse | diminished second | |
|---|---|---|
| Name | ||
| Other names | - | |
| Abbreviation | ? | |
| Size | ||
| Semitones | 12 | |
In music, the interval of an augmented seventh is an interval of a major seventh augmented by a chromatic semitone. It is therefore the difference between the diatonic and chromatic semitones, which makes it a highly variable quantity between one meantone tuning and the next. In standard equal temperament, in fact, it is identical to the perfect octave (
Play (help·info)), because both semitones have the same size. In 19 equal temperament, on the other hand, the interval is 63 cents short of an octave, ie 1137 cents. More typical meantone tunings fall between these extremes, giving it an intermediate size.
In just intonation, three major thirds in succession make up an augmented seventh, which is just short of an octave by 41.05 cents. Adding a diesis to this makes up an octave. Hence, this interval's complement, the diminished second, is often referred to as a diesis.
See also change