An augmented sixth is one of three musical intervals that span six diatonic scale degrees. The prefix 'augmented' identifies it as being the largest of the three intervals; the others being the major sixth and minor sixth, which are one and two semitones smaller, respectively. Its inversion is the diminished third, and its enharmonic equivalent is the minor seventh. In music theory, an interval is the difference (a ratio or logarithmic measure) in pitch between two notes and often refers to those two notes themselves (otherwise known as a dyad). ... Jump to: navigation, search In music theory, a diatonic scale (from the Greek diatonikos, to stretch out) is a seven-note musical scale comprising five whole-tone and two half-tone steps, in which the half tones are maximally separated. ... The musical interval of a major sixth is the relationship between the first note (the root or tonic) and the sixth note in a Major scale. ... Jump to: navigation, search A minor sixth is the smaller of two commonly occuring musical intervals that span six diatonic scale degrees. ... The musical interval of a half step, semitone, or minor second is the relationship between the leading tone and the first note (the root or tonic) in a major scale. ... Inversion has different meanings in different fields of knowledge: Something that is inverted or the process by which an inverse is obtained. ... In music, an enharmonic is a note which is the equivalent of some other note, but spelled differently. ... The musical interval of a minor seventh the first note (the root or tonic) and the seventh in a minor scale. ...

In the tuning system known as equal temperament the augmented sixth is equal to ten semitones and is a dissonant interval. Equal temperament is a scheme of musical tuning in which the octave is divided into a series of equal steps (equal frequency ratios). ... In music, a consonance (Latin consonare, sounding together) is a harmony, chord, or interval considered stable, as opposed to a dissonance, which is considered unstable. ...

The augmented sixth is relatively rare. Its most common occurrence is built on the lowered submediant of the prevailing key, in which position the interval assumes a natural tendency to resolve by expanding to an octave built on the dominant tonal degree. In its most common and expected resolution, the lower note of the interval moves downwards by a minor second to the dominant while the upper note, being chromatically inflected, is heard as the leading note of the dominant key, rising naturally by a minor second. It is the strong tendency to resolve in this way that properly identifies this interval as being an augmented sixth rather than its more common enharmonic equivalent: the minor seventh, which has a tendency to resolve inwardly. In music, the submediant is the sixth degree of the scale. ... In music, an octave (sometimes abbreviated 8ve or 8va) is the interval between one musical note and another with half or double the frequency. ... The word dominant has several possible meanings: In music theory, the dominant or dominant note (second most important) of a key is that which is a perfect fifth above the tonic; in just intonation the note whose pitch is 1. ... Jump to: navigation, search A minor second is the smallest of three commonly occuring musical intervals that span two diatonic scale degrees; the others being the major second and the augmented second, which are larger by one and two semitones respectively. ...

As the augmented sixth is correctly named only in certain specific contexts, the notational distinction between it and the identical sounding minor seventh is often ignored. Regardless of the true diatonic context, many writers choose in favour of the more familiar minor seventh - especially in chord notation, in which chords containing it are always labelled seventh chords. In Music theory, the diatonic major scale (also known as the Guido scale), from the Greek diatonikos or to stretch out, is a fundamental building block of the European-influenced musical tradition. ... A seventh chord is a chord or triad which has a note the seventh above the tonic in it. ...

The augmented sixth interval in combination with certain others forms the group of chords known collectively as 'augmented sixth chords', detailed below.

Augmented 6th chord

The Augmented sixth chord is a chromatic chord built on the flattened submediant of a scale, and is thus given the simple Roman notation bVI. It generally resolves to chord V but it may resolve to the tonic in second inversion (Ic). There are 3 types of augmented 6th, the French, Italian and German. These names are purely used to destinguish the different chords: The term chromatic chords is used to broadly describe chords used to harmonise a piece of music that are not drawn from the true notes of the scale of the key of the piece but are based on chromatically altered notes of the scale. ...

Italian: contains the flattened submediant, tonic and sharpened subdominant of the scale, for example Ab, C and F# in the key of C. This chord sounds like Ab7. The Ab and F# resolve to G and the C resolves to B in the key of C.

French: this is the same as the Italian sixth but also contains the supertonic of the scale. In the key of C, this is D and does not require resolution as this note is the fifth of chord V.

German: this is the same as the Italian sixth but also contains the flattened mediant of the scale. In the key of C, this is Eb which resolves down to D in chord V. If the flattened mediant undergoes an enharmonic change to the sharpened supertonic (D# here), the notes may resolve to Ic (D# resolves to E, C remains as C).