6561/6250

6561/6250, the ripple or 5/12-meantone semitone, is a 5-limit ratio of about 84.07 cents.

Theory

The interval can be treated equally either as a comma, which results in the Ripple family, or as a melodic interval in its own right, where it is exactly replicated in 5/12-comma meantone. The 5/12CM-meantone is represented well in 400edo, where 6561/6250 is approximated by 28 steps and the generator fifth by 231 steps.

As a comma, it represents the difference between 27/16 and 5 5/3s, or 4 10/9s and one 8/5.