User:VectorGraphics/Periodicity: Difference between revisions

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== From temperaments to scales ==
== From temperaments to scales ==
[[File:12 well 5limit.png|left|thumb|337x337px|A well temperament of 12-edo defined from a Fokker periodicity block, in ratios and in cents. (Both possible mappings of 600c have been provided.)]]
[[File:12 well 5limit.png|left|thumb|337x337px|A well temperament of 12-edo defined from a Fokker periodicity block, in ratios and in cents. (Both possible mappings of 600c have been provided.)]]
Such a block can then be placed back into a less restrictive temperament or into just intonation, to define a scale, sort of like a MOS scale but generalized to a higher dimension. For example, one might describe a 12-tone well temperament in 5-limit just intonation by placing a periodicity block representing 12edo into a JI lattice, and seeing what intervals lie within it.
Such a block can then be placed back into a less restrictive temperament or into just intonation, to define a scale, sort of like a MOS scale but generalized to a higher dimension. For example, one might describe a 12-tone well temperament in 5-limit just intonation by placing a periodicity block representing 12edo into a JI lattice, and seeing what intervals lie within it. This can be treated as a scale on its own (a just chromatic scale), outside of the context of being a 12edo detemper.


In the context of constructing a scale (as opposed to defining a temperament), the intervals chosen at which to repeat the table are called '''chromas''' instead of commas, and they define a '''chroma basis'''. So, for example, our 12-well temperament has the chroma basis {81/80, 128/125}.
In the context of constructing a scale (as opposed to defining a temperament), the intervals chosen at which to repeat the table are called '''chromas''' instead of commas, and they define a '''chroma basis'''. So, for example, our 12-well temperament has the chroma basis {81/80, 128/125}.