540/539, the swetisma, is a comma in the 11-limit, equal to (15/11)/(7/6)2, to (12/11)(15/14)/(7/6) or to (99/98)/(121/120). Thus, tempering any two of 99/98, 121/120 and 540/539 will result in the third of the three being tempered, resulting in the rank-3 temperament Big Brother. More generally, tempering 540/539 leads to swetismic temperaments.
- Swetismic chords
- Rank-4 temperament #Swetismic (540/539)
- Swetismic temperaments, a collection of rank-3 temperaments where it is tempered out
- Unnoticeable comma
- List of superparticular intervals