31-limit: Difference between revisions
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== Intervals == | == Intervals == | ||
Here is a table of all 31-limit intervals with at most two primes from 5 to 31 in the ratio (excepting 5-limit intervals, which have at most three) — vertical axis, on a chain of 53 [[3-limit|harmonic fifths]] — horizontal axis. | Here is a table of all 31-limit intervals with at most two primes from 5 to 31 in the ratio (excepting 5-limit intervals, which have at most three) — vertical axis, on a chain of 53 [[3-limit|harmonic fifths]] — horizontal axis. | ||
The rules to get this table are: | |||
# 1/1 is the center of symmetry between reciprocals. | |||
# The positive abscissa is the positive [[3-limit|Pythagorean scale]]. The negative abscissa is deducted by rule 1. | |||
# The positive ordinate is the positive quasi-primes scale (one or two primes in the ratio), in this logical order: | |||
::* a ; a*a ; | |||
::* 5-limit allows also a*a*a to show the worth mentioning [[128/125|diesis]] in its symmetrical reciprocal | |||
::* b ; a*b ; a<sup>-1</sup>*b ; b*b ; | |||
::* c ; a*c ; a<sup>-1</sup>*c ; b*c ; b<sup>-1</sup>*c ; c*c ; | |||
::* d ; a*d ; a<sup>-1</sup>*d ; b*d ; b<sup>-1</sup>*d ; c*d ; c<sup>-1</sup>*d ; d*d ; | |||
::* e ; a*e ; a<sup>-1</sup>*e ; b*e ; b<sup>-1</sup>*e ; c*e ; c<sup>-1</sup>*e ; d*e ; d<sup>-1</sup>*e ; e*e ; | |||
::* etc... | |||
: The negative ordinate is deducted by rule 1. | |||
For each intervals, you'll find: its factorization (ignoring octaves), its just ratio, its [[Functional Just System|Functional Just System]] notation, and its cents value (rounded to 9 decimal places). | For each intervals, you'll find: its factorization (ignoring octaves), its just ratio, its [[Functional Just System|Functional Just System]] notation, and its cents value (rounded to 9 decimal places). | ||