Cross-set scale: Difference between revisions
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A '''cross-set scale''' is a [[scale]] produced by taking every ordered pair in the [[Wikipedia:Cartesian product|Cartesian product]] of two | A '''cross-set scale''' (or simply '''cross-set''') is a [[scale]] produced by taking every ordered pair in the [[Wikipedia:Cartesian product|Cartesian product]] of two scales, or of a scale with itself, and stacking all elements in each ordered pair. Cross-set scales may also be generalized to more than two initial scales. | ||
If the second scale is the inverse of the first scale (e.g. ''a'' becomes 1/''a''), the result is a reciprocal cross-set (scale). If additionally the first scale is a sequence of odd harmonics starting from 1, the result is a [[tonality diamond]]. | |||
The term ''cross-set'' goes back to [[Erv Wilson]].<ref name="Narushima 2017">Narushima, T. (2017). Microtonality and the tuning systems of Erv Wilson. Routledge.</ref> | |||
== Example == | |||
= | The 4:5:6:7 cross-set scale is produced by multiplying every pair of intervals from the 4:5:6:7 tetrad ([[1/1]] - [[5/4]] - [[3/2]] - [[7/4]]), including an interval with itself, and [[Octave reduction|octave-reducing]] as necessary. It contains 10 distinct intervals out of 16 combinations. | ||
The 4:5:6:7 cross-set scale is produced by multiplying every pair of intervals from the 4:5:6:7 tetrad ([[1/1]] - [[5/4]] - [[3/2]] - [[7/4]]), including an interval with itself, and [[Octave reduction|octave-reducing]] as necessary. It contains 10 distinct | |||
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The starting scales do not need to be in [[just intonation]]; a cross-set scale could be constructed from any kind of scale. | The starting scales do not need to be in [[just intonation]]; a cross-set scale could be constructed from any kind of scale. | ||
== Theory == | |||
In mathematical notation, the cross-set of scales ''A'', ''B'', ..., ''Z'' is (note that interval stacking has been written as addition): | |||
<math>\text{Cross-set}(A, B, ..., Z) = \{ a + b + \cdots + z : (a, b, ..., z) \in A \times B \times \cdots \times Z\}.</math> | |||
In combinatorics, this operation is called a [[wikipedia:Sumset|sumset]]. | |||
== Music == | == Music == | ||
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; [[Frédéric Gagné]] | ; [[Frédéric Gagné]] | ||
* [https://musescore.com/user/5995996/scores/11287339 | * [https://musescore.com/user/5995996/scores/11287339 ''Floating in Outer Space''] | ||
== References == | == References == | ||
<references /> | |||
[[Category:Scale]] | [[Category:Scale]] | ||