German sixth chord: Difference between revisions

Rework part of the meantone section as quarter-comma meantone is a specific instance of septimal meantone. The harmonic seventh chord should remain highlighted as it's the focus nowadays.
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clarify meantone vs. septimal meantone in chord summaries
 
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== In meantone ==
== In meantone ==
In [[meantone]], the augmented sixth represents both [[125/72]] and [[225/128]]. Most meantone tunings has this interval placed near [[7/4]]. In the historically-prevalent [[quarter-comma meantone]], for example, it is tuned only a few cents shy of a just 7/4, so the meantone German sixth chord can be considered to approximate the [[harmonic seventh chord]]:


* 1 – 5/4 – 3/2 – 7/4 with steps 5/4, 6/5, 7/6.
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 German sixth chord,
 
* (Meantone) 1 – 5/4 – 3/2 – 125/72
 
simultaneously represents both [[72:90:108:125]] (with steps 5/4, 6/5, and [[125/108]]) and [[128:160:192:225]] (with steps 5/4, 6/5, and [[75/64]]).
 
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 German sixth chord can be considered to approximate the ''harmonic seventh chord'' as in [[septimal meantone]]:
 
* (Septimal meantone) 1 – 5/4 – 3/2 – 7/4
 
representing [[4:5:6:7]] (with steps 5/4, 6/5, and 7/6).
<!-- 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 German sixth. -->


== In just intonation ==
== In just intonation ==
Because the German sixth chord is often built on the sixth degree of a minor scale, the [[128:160:192:225]] found on the ♭VI of the [[duodene]] is a good candidate for its interpretation in the [[5-limit]].
 
In the [[5-limit]]:
 
* [[128:160:192:225]], one of the possible 5-limit interpretations of the meantone chord, is found rooted at the ♭II ({{Frac|16|15}}) and ♭VI ({{Frac|8|5}}) of the [[duodene]].
 
[[Category:Just intonation chords]]
[[Category:German sixth chords| ]] <!-- main article -->