User:Eliora/Concoctic scale: Difference between revisions

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The length of a maximum evenness scale's generator can be determined through a '''modular multiplicative inverse''' of the note amount and the tuning size<ref>https://individual.utoronto.ca/kalendis/leap/index.htm</ref>:
The length of a maximum evenness scale's generator can be determined through a '''modular multiplicative inverse''' of the note amount and the tuning size<ref>https://individual.utoronto.ca/kalendis/leap/index.htm</ref>:


<math>ax \equiv 1 \mod N</math>,
<math>ax \equiv 1\mod N</math>,


where N is the period, and a is the note count. Therefore, a concoctic scale is defined for a given N:
where N is the period, and a is the note count. Therefore, a concoctic scale is defined for a given N:


<math>aa \equiv 1 \mod N</math>,
<math>aa \equiv 1\mod N</math>,


which simply becomes
which simply becomes


<math>a^2 \equiv 1 \mod N</math>.
<math>a^2 \equiv 1\mod N</math>.


Paraconcoctic scales are those, which in a pure sense are the octave inversions of one another. For example, a {7/10}'s generator is 3, and of {3/10} is 7. Since octave-inverting the MOS generator has no impact on the scale, paraconcoctic scales are identical to their usual counterparts. However, the difference is pronounced in keyboard making - in paraconcoctic scales, white keys' generator will be the amount of black keys and vice versa. The formula for such a scale is  
There are also paraconcoctic scales, or chroma-negative concoctic scales. The formula for such a scale is  


<math>a^2 \equiv -1 \mod N</math>
<math>a^2 \equiv -1\mod N</math>.
 
Since octave-inverting the MOS generator has no impact on the scale, paraconcoctic scales are identical to their usual, orthoconcoctic counterparts. However, the difference is pronounced in keyboard making - in terms of chroma direction, the white keys' generator will be the amount of black keys and vice versa.
 
=== Example ===
12edo keyboard layout predominantly in use in the world today features 7 white keys and 5 black keys. The diatonic scale of 7 keys is obtained by stacking the generator, 7\12 fifth 7 times. Likewise, the pentatonic of black keys is obtained by stacking it 5 times.


== List ==
== List ==