81/80 equal-step tuning
81/80 equal-step tuning (AS81/80, ambitonal sequence 81/80) is an equal multiplication of the syntonic comma. It corresponds to 55.79763 edo.
81/80 equal-step tuning can be regarded as a subset of 5-limit just intonation. Some intervals it approximates well are 5/4, 7/4, 12/11, 14/13, and 15/11. In addition, it represents well certain compound intervals such as 8/3, 11/1, 12/1 while omitting their octave reductions. With a stretch, 53edo can be regarded as its edo equivalent. However, the closest direct approximation is 56edo.
AS81/80 has a good representation of the 11.17.19 prime number subgroup. This time, the octave equivalence is not applied.