1156/1155
Interval information |
reduced
1156/1155 is a 17-limit no-13 superparticular comma measuring about 1.41 cents. It may be properly described as the septendecimal quartertones comma, since it is the difference between 34/33 and 35/34, the two 17-limit quartertone.
In terms of commas, it is the difference between 289/288 and 385/384, and between 936/935 and 4914/4913. It factors into (2080/2079)(2601/2600), or (1275/1274)(12376/12375).
Temperaments
Tempering out this comma results in 35/33 being split into two equal parts, each representing 34/33~35/34, and enables the related essentially tempered chords. If 9801/9800 is also added to the comma list, the quartertone above becomes literally a quarter of 9/8 and is located right between 33/32, the undecimal quartertone, and 36/35, the septimal quartertone.