2187/2176
| Ratio | 2187/2176 |
| Subgroup monzo | 2.3.17 [-7 7 -1⟩ |
| Size in cents | 8.7295966¢ |
| Name | septendecimal schisma |
| Color name | L17u-2, lasu negative 2nd, Lasu comma |
| FJS name | [math]\text{d}{-2}_{17}[/math] |
| Special properties | reduced |
| Tenney height (log2 nd) | 22.1822 |
| Weil height (log2 max(n, d)) | 22.1895 |
| Wilson height (sopfr(nd)) | 52 |
| Harmonic entropy (Shannon, [math]\sqrt{nd}[/math]) |
~1.88062 bits |
| Comma size | small |
| open this interval in xen-calc | |
The septendecimal schisma[1], 2187/2176, is a small 17-limit comma measuring about 8.7 ¢.
Although several times in size, it shares similarities with the schisma – while the schisma is the amount by which 16/15 deviates from 2187/2048, the septendecimal schisma is the amount by which 17/16 deviates from 2187/2048, which means it is the difference between 17th harmonic and a stack of seven 3/2 perfect fifths.
Besides the relationship above, it is also the difference between 18/17 and 256/243, between 24/17 and 1024/729, and their respective inverses. Furthermore, it and the septendecimal comma 4131/4096 make a Pythagorean comma.
The septendecimal schisma is significant in Helmholtz-Ellis notation (2020 version) as the 17-limit formal comma which translates a Pythagorean interval to a nearby septendecimal interval. Consequently, 17/16 is represented as an augmented unison. In the Functional Just System, however, that role is taken by 4131/4096, so 17/16 is represented as a minor second.