Phaotic comma

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Interval information
Ratio 256000/255879
Monzo [11 -9 3 0 0 1
Size in cents 0.81847
Name(s) phaotic comma,
phaotisma
open this interval in xen-calc

The phaotic comma, or phaotisma (from Ancient Greek pháos 'light'), is an unnoticeable 13-limit (also 2.3.5.13 subgroup) comma with a ratio of 256000/255879, and a size of approximately 0.82 cents. It is significant in that it is the interval separating a stack of two meantone commas from 40/39, as well as the interval separating an octave-reduced stack of three instances of 27/20 from 16/13.

Temperaments

Tempering it out splits 40/39 into two equal halves, each representing 81/80. It leads to a form of phaotismic temperament in the full 13-limit and phaotic temperament in the 2.3.5.13 subgroup.

See also