Acoustic pi

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Pi, the ratio of a circle's circumference to its octave, is equal to about 3.14159. When used as an equivalence interval, it becomes a rather minor thirteenth of 1981.795 cents.

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Intervals that are close to it are 3/1, 22/7, and 355/113.

Equal divisions

Using 3.14159.../1 as an interval of equivalence results in an interesting nonoctave tuning.

EDπ-ED2 correspondence
N Description
2edπ A stack of two minor sevenths, represents a problem of squaring the circle
3edπ A stack of three compressed fifths, vaguely equivalent to 2edo
4edπ Close to equal multiplication of 4/3
5edπ Close to equal multiplication of 5/4, 3edo
6edπ Close to equal multiplication of 6/5, 4edo
20edπ Close to 12edo.

Temperaments of interest

Engineer's temperament, tempering out π/3, the engineer's comma.