Italian sixth chord: Difference between revisions
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{{Wikipedia|Augmented sixth chord #Italian sixth}} | {{Wikipedia|Augmented sixth chord #Italian sixth}} | ||
An '''Italian sixth chord''' is a [[triad]] comprising a root, major third, and augmented sixth. | An '''Italian sixth chord''' is a [[triad]] comprising a root, major third, and augmented sixth. It is often considered to contain four voices, with the major third doubled. | ||
== In meantone == | == In meantone == | ||
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In 5-limit meantone, the traditional foundation of tonal harmony, the augmented sixth represents both [[225/128]] and [[125/72]]. It is treated as a rare and special dissonance, especially when used on the sixth degree. The 5-limit meantone Italian sixth chord, | In 5-limit meantone, the traditional foundation of tonal harmony, the augmented sixth represents both [[225/128]] and [[125/72]]. It is treated as a rare and special dissonance, especially when used on the sixth degree. The 5-limit meantone Italian sixth chord, | ||
* (Meantone) | * (Meantone) 1–5/4–5/4–125/72 | ||
simultaneously represents both [[72:90:125]] (with steps 5/4 and [[25/18]]) and [[128:160:225]] (with steps 5/4 and [[45/32]]). | simultaneously represents both [[72:90:125|72:90:90:125]] (with steps 5/4, 1/1 and [[25/18]]) and [[128:160:225|128:160:160:225]] (with steps 5/4, 1/1 and [[45/32]]). | ||
However, in the historically prevalent [[quarter-comma meantone]], the augmented sixth is tuned only a few cents shy of a just [[7/4]], so the meantone Italian sixth chord can be considered to approximate the [[septimal meantone]] chord: | However, in the historically prevalent [[quarter-comma meantone]], the augmented sixth is tuned only a few cents shy of a just [[7/4]], so the meantone Italian sixth chord can be considered to approximate the [[septimal meantone]] chord: | ||
* (Septimal meantone) | * (Septimal meantone) 1–5/4–5/4–7/4 | ||
representing [[4:5:7]] (with steps 5/4 and 7/5). | representing [[4:5:7|4:5:5:7]] (with steps 5/4, 1/1 and 7/5). | ||
<!-- Note: The close approximation of 7/4 is specific to quarter-comma meantone. Many other meantones, such as 12edo and 19edo, do not approximate it nearly as closely, although they may nonetheless support the septimal meantone interpretation that unifies it with the Italian sixth. --> | <!-- Note: The close approximation of 7/4 is specific to quarter-comma meantone. Many other meantones, such as 12edo and 19edo, do not approximate it nearly as closely, although they may nonetheless support the septimal meantone interpretation that unifies it with the Italian sixth. --> | ||
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In the [[5-limit]]: | In the [[5-limit]]: | ||
* [[128:160:225|128:160:160:225]], one of the possible 5-limit interpretations of the meantone chord, is found rooted at ♭II ({{Frac|16|15}}) and ♭VI ({{Frac|8|5}}) in the [[duodene]]. | |||
* [[128:160:225]], one of the possible 5-limit interpretations of the meantone chord, is found rooted at ♭II ({{Frac|16|15}}) and ♭VI ({{Frac|8|5}}) in the [[duodene]]. | |||
[[Category:Just intonation chords]] | [[Category:Just intonation chords]] | ||
[[Category:Italian sixth chords| ]] <!-- main article --> | [[Category:Italian sixth chords| ]] <!-- main article --> | ||
Latest revision as of 07:36, 23 May 2026
An Italian sixth chord is a triad comprising a root, major third, and augmented sixth. It is often considered to contain four voices, with the major third doubled.
In meantone
In 5-limit meantone, the traditional foundation of tonal harmony, the augmented sixth represents both 225/128 and 125/72. It is treated as a rare and special dissonance, especially when used on the sixth degree. The 5-limit meantone Italian sixth chord,
- (Meantone) 1–5/4–5/4–125/72
simultaneously represents both 72:90:90:125 (with steps 5/4, 1/1 and 25/18) and 128:160:160:225 (with steps 5/4, 1/1 and 45/32).
However, in the historically prevalent quarter-comma meantone, the augmented sixth is tuned only a few cents shy of a just 7/4, so the meantone Italian sixth chord can be considered to approximate the septimal meantone chord:
- (Septimal meantone) 1–5/4–5/4–7/4
representing 4:5:5:7 (with steps 5/4, 1/1 and 7/5).
In just intonation
In the 5-limit:
- 128:160:160:225, one of the possible 5-limit interpretations of the meantone chord, is found rooted at ♭II (16⁄15) and ♭VI (8⁄5) in the duodene.