4:6:7

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Chord information
Harmonics 4:6:7
Subharmonics 1/(21:14:12)
Intervals from root 1/13/27/4
Cents from root 702¢969¢
Step intervals 3/2, 7/6
Step cents 702¢, 267¢
Color names yo zo-7 no-5 or y,z7no5
har-7 no-5 or h7no5
Prime limit 7
Genus 37 (21)
Intervallic odd limit 7
Otonal odd limit 7
Utonal odd limit 21
Consistent edos (d ≥ 2) 5edo**, 10edo*, 22edo*, 26edo*, …

4:6:7 is a 7-limit chord found as a subset of the harmonic seventh chord, 4:5:6:7. Due to having no fives, it is the first otonal chord that deviates from traditional harmony. As such, it is a candidate for metallic harmony, a form of extraclassical tonality that employs 7 instead of 5 as its other prime.

Its first rotation, 6:7:8, is significant because it consists of the intervals 7/6 and 8/7 stacked on top of each other. The intervals in this chord divide the perfect fourth rather than the perfect fifth, and contrast by 49/48, similarly to how 5/4 and 6/5 contrast by 25/24 in 4:5:6. By swapping the order of 7/6 and 8/7, we get the utonal inverse of 6:7:8, that being 1/(8:7:6) = 21:24:28.

Another notable setting is the open voicing 4:7:12, which shares the property with 6:7:8 that its intervals, 7/4 and 12/7, contrast by 49/48, but they divide the perfect twelfth instead. This also has the advantage of avoiding the unresolvedness of a dominant seventh chord that occurs in the 6:7:8 and 4:6:7 voicings. Its utonal version is 7:12:21, an open voicing of 14:21:24.

Rotations around the octave

4:6:7 "Root position"
6:7:8 "1st inversion"
7:8:12 "2nd inversion"


Edo approximations for 4:6:7 
intervals: 3/2, 7/4 · ≤ 60edo, RMS rel. error ≤ 15%
  Edo Steps Cents (¢) Absolute errors (¢) RMS (¢) RMS (%)
9 0  5  7 0.00 666.67 933.33 0.00 -35.29 -35.49 16.68 12.51
10 0  6  8 0.00 720.00 960.00 0.00 +18.04  -8.83 11.18 9.32
14 0  8 11 0.00 685.71 942.86 0.00 -16.24 -25.97 10.71 12.50
15 0  9 12 0.00 720.00 960.00 0.00 +18.04  -8.83 11.18 13.98
17 0 10 14 0.00 705.88 988.24 0.00  +3.93 +19.41 8.38 11.87
19 0 11 15 0.00 694.74 947.37 0.00  -7.22 -21.46 8.91 14.12
21 0 12 17 0.00 685.71 971.43 0.00 -16.24  +2.60 8.34 14.59
22 0 13 18 0.00 709.09 981.82 0.00  +7.14 +12.99 5.31 9.74
26 0 15 21 0.00 692.31 969.23 0.00  -9.65  +0.40 4.65 10.07
27 0 16 22 0.00 711.11 977.78 0.00  +9.16  +8.95 4.27 9.61
31 0 18 25 0.00 696.77 967.74 0.00  -5.18  -1.08 2.23 5.76
32 0 19 26 0.00 712.50 975.00 0.00 +10.54  +6.17 4.33 11.54
36 0 21 29 0.00 700.00 966.67 0.00  -1.96  -2.16 0.97 2.92
37 0 22 30 0.00 713.51 972.97 0.00 +11.56  +4.15 4.78 14.74
41 0 24 33 0.00 702.44 965.85 0.00  +0.48  -2.97 1.53 5.22
46 0 27 37 0.00 704.35 965.22 0.00  +2.39  -3.61 2.47 9.46
48 0 28 39 0.00 700.00 975.00 0.00  -1.96  +6.17 3.46 13.86
51 0 30 41 0.00 705.88 964.71 0.00  +3.93  -4.12 3.29 13.96
53 0 31 43 0.00 701.89 973.58 0.00  -0.07  +4.76 2.26 9.98
58 0 34 47 0.00 703.45 972.41 0.00  +1.49  +3.59 1.47 7.11

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