Equiheptatonic
Equiheptatonic scales are heptatonic scales with 7 roughly equally spaced tones per octave.
They are usually not exactly equally spaced, but deviate from equal by small amounts, often to improve the tuning of 3/1 and 5/1.
Musical traditions that make use of equiheptatonic scales include:
- Eastern Angolan music
- Ancient Chinese music
- Ancient Greek auloi music
- Chopi music from Mozambique (inspired Erv Wilson to create the mavila temperament)
- Mande music from West Africa
- Shona music from Zimbabwe
- Lower Zambezi music
- Cambodian classical music (disputed[1])
- Laotian classical music (disputed[1])
- Thai classical music (disputed[1])
- Vietnamese classical music (disputed[1])
Note that just because a tradition has an equiheptatonic scale doesn’t mean it uses it exclusively. They often have other tunings too. Also, the term “scale” here is used loosely, because many, perhaps the majority, of musical traditions don’t use scales, but use something else like tetrachords, raag, etc. that scales can only loosely model.
An exactly equal equiheptatonic scale equals 7edo, which is popular with modern Western xenharmonic composers.
Equiheptatonic scales in edos
All multiple-of-7 edos (7, 14, 21, 28, 35…) contain the exactly equal 7edo equiheptatonic scale.
In most traditions that use them, equiheptatonic scales are slightly unequal and slightly closer to just (rarely slightly further from, but only by a tiny amount). There are a diverse array of those used in different regions.
For that reason, it might be more fruitful for composers to explore edos with equiheptatonic scales that share those characteristics. that is, after all, its own diverse array of subtly different equiheptatonic scales.
Such edos include:
- 1edo to 40edo
- 41edo to 60edo
43, 45, 47, 50, 52, 54, 57, 59
- 61edo to 80edo
61, 64, 66, 68, 71, 73, 75, 78, 80
- 81edo to 100edo
82, 85, 86, 87, 89, 92, 93, 94, 96, 99, 100
From the list it can be seen that edos with this type of equiheptatonic scale are often runoff edos[idiosyncratic term], they are often dual-fifth edos and they often support flattone, flattertone, or a related temperament. None of these things are always true: just true more often than chance.
See also
- Equipentatonic
- African music
- Macrotonal NEJI edos: the 7-tone ones are examples of equiheptatonic scales
Notes
- ↑ 1.0 1.1 1.2 1.3 Garzoli, John. The Myth of Equidistance in Thai Tuning.