100/99: Difference between revisions
Cleanup |
m recat, added FJS name, size to 5 digits |
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| Ratio = 100/99 | | Ratio = 100/99 | ||
| Monzo = 2 -2 2 0 -1 | | Monzo = 2 -2 2 0 -1 | ||
| Cents = 17. | | Cents = 17.39948 | ||
| Name = Ptolemy's comma, <br>ptolemisma | | Name = Ptolemy's comma, <br>ptolemisma | ||
| Color name = 1uyy1, luyoyo comma | | Color name = 1uyy1, luyoyo comma | ||
| FJS name = A1<sup>25</sup><sub>11</sub> | |||
| Sound = | | Sound = | ||
}} | }} | ||
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== See Also == | == See Also == | ||
* [[Gallery of just intervals]] | * [[Gallery of just intervals]] | ||
[[Category:11-limit]] | [[Category:11-limit]] | ||
[[Category:comma]] | [[Category:Small comma]] | ||
[[Category: | [[Category:Superparticular]] | ||
Revision as of 17:06, 25 September 2020
| Interval information |
ptolemisma
reduced
In just intonation, 100/99, the Ptolemy's comma or ptolemisma, is a superparticular interval of around 17.4¢ which makes the difference between 11/10, the greater undecimal neutral second of about 165¢, and 10/9, the 5-limit minor whole tone of about 182.4¢. Temperaments in which 100/99 is tempered out include 22edo, 41edo and others; in such systems, 11/10 and 10/9 are equated. This is in contrast to the more familiar tempering out of 81/80, which results in meantone and other temperaments, in which 10/9 is equated, not with 11/10, but with 9/8. Along with being the difference between 11/10 and 10/9, 100/99 is the amount by which an 11/8 and two 6/5s fall short of an octave, so that tempering out 100/99 allows for the ptolemismic triad which has intervals of 11/8, 6/5, 6/5.