27/20: Difference between revisions
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added the color name |
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| Cents = 519.55129 | | Cents = 519.55129 | ||
| Name = wolf fourth, <br> classic acute fourth | | Name = wolf fourth, <br> classic acute fourth | ||
| Color name = | | Color name = g4, gu 4th | ||
| FJS name = P4<sub>5</sub> | | FJS name = P4<sub>5</sub> | ||
| Sound = jid_27_20_pluck_adu_dr220.mp3 | | Sound = jid_27_20_pluck_adu_dr220.mp3 | ||
Revision as of 05:24, 13 February 2022
| Interval information |
classic acute fourth
[sound info]
In 5-limit just intonation, 27/20, the classic acute fourth, is an interval measuring about 519.6¢. It differs from the 4/3 perfect fourth by 81/80 (about 21.5¢), the syntonic comma. It arises naturally in JI as (for instance) the difference between a 5-limit major third and a stack of five 3/2 perfect fifths, or as the interval between 10/9 and 3/2. In 12edo and meantone systems, this interval would be no different from 4/3, as the syntonic comma is tempered out. 27/20 has been described as a "wolf" interval, implying that it "howls," as compared to simpler intervals within the 5-limit such as 5/4 and 9/8. Although in a 5-limit context it is traditionally avoided, it can be an essential interval in a harmonic context of higher complexity, where it may be admired for its bright and active character and its distinctness from 4/3.