Editing Augmented sixth

{{About|the interval|the chord|Augmented sixth chord}}
{{Infobox Interval|
       main_interval_name = augmented sixth|
       inverse = [[diminished third]]|
       complement = [[diminished third]]|
       other_names = -|
       abbreviation = A6<ref name="B&S"/>|
       semitones = 10|
       interval_class = 2|
       just_interval = 125:72,<ref name="Haluska">Haluska, Jan (2003). ''The Mathematical Theory of Tone Systems'', p.xxvi. {{ISBN|0-8247-4714-3}}. Classic augmented sixth.</ref> 225:128,<ref>Haluska, ibid. Augmented sixth.</ref> 7:4{{citation needed|date=August 2024}}, 59049:32768{{citation needed|date=August 2024}}| 
       cents_equal_temperament = 1000|
       cents_24T_equal_temperament = |
       cents_just_intonation = 955, 977, 969, 1020
}}

[[File:Augmented sixth on C.png|thumb|right|Augmented sixth {{audio|Minor seventh on C.mid|Play}}.]]

In [[music]], an '''augmented sixth''' ({{Audio|Minor seventh on C.mid|Play}}) is an [[Interval (music)|interval]] produced by [[Augmentation (music)|widening]] a [[major sixth]] by a [[chromatic semitone]].<ref name="B&S">Benward & Saker (2003). ''Music: In Theory and Practice, Vol. I'', p.54. {{ISBN|978-0-07-294262-0}}. Specific example of an A6 not given but general example of augmenting major intervals described.</ref><ref>Hoffmann, F.A. (1881). ''Music: Its Theory & Practice'', p.89-90. Thurgate & Sons. Digitized Aug 16, 2007. Archaic: '''superfluous''' or '''extreme sharp sixth'''.</ref> For instance, the interval from C to A is a major sixth, nine semitones wide, and both the intervals from C{{Music|b}} to A, and from C to A{{Music|sharp}} are augmented sixths, spanning ten semitones. Being augmented, it is considered a [[consonance and dissonance|dissonant]] interval.<ref>Benward & Saker (2003), p.92.</ref>

Its [[Inverted chord|inversion]] is the [[diminished third]], and its [[enharmonic]] equivalent is the [[minor seventh]].

In [[septimal meantone temperament]], it is specifically equivalent to the [[harmonic seventh]] (a [[just intonation|just interval]] of 7:4). In 12-tone [[equal temperament]], the augmented sixth is equal to ten semitones and is a [[consonance and dissonance|dissonant]] interval.

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 (music)|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.

As the augmented sixth is correctly named only in certain specific contexts, the notational distinction between it and the minor seventh is often ignored. Regardless of the true [[diatonic]] context, many writers are instead in favor of the more familiar minor seventh – especially in chord notation, in which chords containing it are always labeled [[seventh chord]]s.

The augmented sixth interval in combination with certain other intervals forms the group of chords known collectively as [[augmented sixth chord]]s.

The just augmented sixth arises in the extended C major scale between A{{music|b}} and F{{music|#}}.<ref>Paul, Oscar (1885). ''[https://books.google.com/books?id=4WEJAQAAMAAJ&q=musical+interval+%22pythagorean+major+third%22 A manual of harmony for use in music-schools and seminaries and for self-instruction]'', p.165. Theodore Baker, trans. G. Schirmer.</ref> {{audio|Just augmented sixth in scale.mid|Play}}

==See also==
* [[Augmented sixth chord]]
* [[List of meantone intervals]]

==References==
<references />

==Further reading==
*Hewitt, Michael (2000). ''The Tonal Phoenix: A Study of Tonal Progression Through the Prime Numbers Three, Five and Seven''. Orpheus-Verlag. {{ISBN|978-3922626961}}

{{Intervals}}

[[Category:Augmented intervals]]
[[Category:Sixths (music)]]