- Septimal major third
Infobox Interval| main_interval_name = Septimal major third
inverse =Septimal minor sixth
complement =Septimal minor sixth
other_names = Supermajor third | abbreviation = M3
semitones = ~4 | interval_class = ~4 | just_interval = 9:7| cents_equal_temperament = 400| cents_just_intonation = 435Inmusic , the septimal major third Audio|Septimal major third on C.mid|play, also called the "supermajor third" (byHermann Helmholtz ) and sometimes "Bohlen-Pierce third" is the musical interval exactly or approximately equal to a 9:7 ratio of frequencies. In terms of cents, it is 435 cents, sharper than a justmajor third of 5:4 by theseptimal quarter tone , 36:35 (Audio|Septimal quarter tone on C.mid|play).The septimal major third has a characteristic brassy sound which is much less sweet than a pure major third, but is classed as a 9-limit consonance. Together with the
septimal minor third of 7:6, it makes up the septimal major triad, or supermajor triad Audio|Septimal major triad on C.mid|play. However, in terms of the overtone series, this is autonal rather thanotonal chord, being an inverted6:7:9, ie a #if:|16⁄{3}|#if:6|1⁄6|1⁄1:#if:|17⁄{3}|#if:7|1⁄7|1⁄1:#if:|19⁄{3}|#if:9|1⁄9|1⁄1 chord.In the early meantone era the interval made its appearance as the alternative major third in remote keys, under the name
diminished fourth . Tunings of the meantone fifth in the neighborhood of Zarlino's #if:|27⁄{3}|#if:7|2⁄7|1⁄2-comma meantone will give four septimal thirds among the twelve major thirds of the tuning; this entails that three septimal major triads appear along with one chord containing a septimal major third with an ordinary minor third above it, making up awolf fifth .References
* Hermann Helmholtz and Alexander Ellis (trans), "
On the Sensation of Tone ", Dover Publications
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