17ed4: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
{{ED intro}} It corresponds to 8.5edo or every second step of [[17edo]]. | |||
==Theory== | ==Theory== | ||
17ed4 is the smallest ED4 to contain a diatonic fifth, in this | 17ed4 is the smallest ED4 to contain a diatonic fifth, in this case [[17edo]]'s sharp fifth, and it can be used to generate heptatonic (3L 4s<4/1>) and decatonic ([[7L 3s (4/1-equivalent)|7L 3s<4/1>]]) MOS scales with a period of [[4/1]]. The decatonic scale is the more usable of these two scales, corresponding to an octave-repeating pentatonic scale in terms of step sizes, while the heptatonic scale has too large step sizes, corresponding to an octave-repeating tritonic or tetratonic scale in terms of step sizes. | ||
==Intervals== | ==Intervals== | ||
{|class="wikitable" | {|class="wikitable" | ||
Line 10: | Line 12: | ||
!Approximate ratios | !Approximate ratios | ||
![[17edo]] notation | ![[17edo]] notation | ||
![[7L 3s (4/1-equivalent)| | ![[7L 3s (4/1-equivalent)|Diaquadic]] notation (J = 1/1) | ||
|- | |- | ||
|0 | |0 | ||
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|[[13/12]], [[12/11]], [[14/13]], [[25/23]] | |[[13/12]], [[12/11]], [[14/13]], [[25/23]] | ||
|C# | |C# | ||
|J#, | |J#, Kb | ||
|- | |- | ||
|2 | |2 | ||
Line 28: | Line 30: | ||
|[[13/11]], [[7/6]] | |[[13/11]], [[7/6]] | ||
|Eb | |Eb | ||
| | |K | ||
|- | |- | ||
|3 | |3 | ||
Line 34: | Line 36: | ||
|[[32/25]], [[9/7]], [[14/11]], [[33/26]], [[23/18]] | |[[32/25]], [[9/7]], [[14/11]], [[33/26]], [[23/18]] | ||
|E | |E | ||
|K | |K#, Lb | ||
|- | |- | ||
|4 | |4 | ||
Line 40: | Line 42: | ||
|[[11/8]], [[18/13]], [[32/23]] | |[[11/8]], [[18/13]], [[32/23]] | ||
|^F | |^F | ||
| | |L | ||
|- | |- | ||
|5 | |5 | ||
Line 46: | Line 48: | ||
|[[3/2]], [[32/21]] | |[[3/2]], [[32/21]] | ||
|G | |G | ||
| | |M | ||
|- | |- | ||
|6 | |6 | ||
Line 52: | Line 54: | ||
|[[13/8]], [[18/11]], [[23/14]] | |[[13/8]], [[18/11]], [[23/14]] | ||
|G#, vA | |G#, vA | ||
|M | |M#, Nb | ||
|- | |- | ||
|7 | |7 | ||
Line 58: | Line 60: | ||
|[[16/9]], [[7/4]], [[25/14]], [[44/25]], [[23/13]] | |[[16/9]], [[7/4]], [[25/14]], [[44/25]], [[23/13]] | ||
|Bb | |Bb | ||
| | |N | ||
|- | |- | ||
|8 | |8 | ||
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|[[25/13]], [[48/25]], [[27/14]], [[64/33]], [[23/12]] | |[[25/13]], [[48/25]], [[27/14]], [[64/33]], [[23/12]] | ||
|B | |B | ||
|N | |N#, Ob | ||
|- | |- | ||
|9 | |9 | ||
Line 70: | Line 72: | ||
|[[15/7]] | |[[15/7]] | ||
|^C | |^C | ||
| | |O | ||
|- | |- | ||
|10 | |10 | ||
|1411.80 | |1411.80 | ||
|[[16/7]] | |[[9/4]], [[16/7]] | ||
|D | |D | ||
|O | |O#, Pb | ||
|- | |- | ||
|11 | |11 | ||
Line 88: | Line 90: | ||
|[[8/3]] | |[[8/3]] | ||
|F | |F | ||
| | |Q | ||
|- | |- | ||
|13 | |13 | ||
Line 94: | Line 96: | ||
|[[3/1]] | |[[3/1]] | ||
|F# | |F# | ||
|Q | |Q#, Rb | ||
|- | |- | ||
|14 | |14 | ||
Line 100: | Line 102: | ||
|[[16/5]] | |[[16/5]] | ||
|^G, Ab | |^G, Ab | ||
| | |R | ||
|- | |- | ||
|15 | |15 | ||
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|[[10/3]] | |[[10/3]] | ||
|A | |A | ||
|R | |R#, Sb | ||
|- | |- | ||
|16 | |16 | ||
Line 112: | Line 114: | ||
|[[11/3]] | |[[11/3]] | ||
|vB | |vB | ||
| | |S | ||
|- | |- | ||
|17 | |17 | ||
Line 120: | Line 122: | ||
|J | |J | ||
|} | |} | ||
== Harmonics == | |||
{{Harmonics in equal | |||
| steps = 17 | |||
| num = 4 | |||
| denom = 1 | |||
}} | |||
{{Harmonics in equal | |||
| steps = 17 | |||
| num = 4 | |||
| denom = 1 | |||
| start = 12 | |||
| collapsed = 1 | |||
}} | |||
[[Category:Macrotonal]] | [[Category:Macrotonal]] | ||
[[Category:Nonoctave]] | [[Category:Nonoctave]] | ||
{{todo|expand}} |
Latest revision as of 21:18, 31 July 2025
← 15ed4 | 17ed4 | 19ed4 → |
17 equal divisions of the 4th harmonic (abbreviated 17ed4) is a nonoctave tuning system that divides the interval of 4/1 into 17 equal parts of about 141 ¢ each. Each step represents a frequency ratio of 41/17, or the 17th root of 4. It corresponds to 8.5edo or every second step of 17edo.
Theory
17ed4 is the smallest ED4 to contain a diatonic fifth, in this case 17edo's sharp fifth, and it can be used to generate heptatonic (3L 4s<4/1>) and decatonic (7L 3s<4/1>) MOS scales with a period of 4/1. The decatonic scale is the more usable of these two scales, corresponding to an octave-repeating pentatonic scale in terms of step sizes, while the heptatonic scale has too large step sizes, corresponding to an octave-repeating tritonic or tetratonic scale in terms of step sizes.
Intervals
# | Cents | Approximate ratios | 17edo notation | Diaquadic notation (J = 1/1) |
---|---|---|---|---|
0 | 0.00 | 1/1 | C | J |
1 | 141.18 | 13/12, 12/11, 14/13, 25/23 | C# | J#, Kb |
2 | 282.36 | 13/11, 7/6 | Eb | K |
3 | 423.54 | 32/25, 9/7, 14/11, 33/26, 23/18 | E | K#, Lb |
4 | 564.72 | 11/8, 18/13, 32/23 | ^F | L |
5 | 705.90 | 3/2, 32/21 | G | M |
6 | 847.08 | 13/8, 18/11, 23/14 | G#, vA | M#, Nb |
7 | 988.26 | 16/9, 7/4, 25/14, 44/25, 23/13 | Bb | N |
8 | 1129.44 | 25/13, 48/25, 27/14, 64/33, 23/12 | B | N#, Ob |
9 | 1270.62 | 15/7 | ^C | O |
10 | 1411.80 | 9/4, 16/7 | D | O#, Pb |
11 | 1552.98 | 12/5, 5/2 | vE | P |
12 | 1694.16 | 8/3 | F | Q |
13 | 1835.34 | 3/1 | F# | Q#, Rb |
14 | 1976.52 | 16/5 | ^G, Ab | R |
15 | 2117.70 | 10/3 | A | R#, Sb |
16 | 2258.88 | 11/3 | vB | S |
17 | 2400.00 | 4/1 | C | J |
Harmonics
Harmonic | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | +70.6 | -66.7 | +0.0 | +37.2 | +3.9 | +19.4 | +70.6 | +7.9 | -33.4 | -57.2 | -66.7 |
Relative (%) | +50.0 | -47.2 | +0.0 | +26.4 | +2.8 | +13.7 | +50.0 | +5.6 | -23.6 | -40.5 | -47.2 | |
Steps (reduced) |
9 (9) |
13 (13) |
17 (0) |
20 (3) |
22 (5) |
24 (7) |
26 (9) |
27 (10) |
28 (11) |
29 (12) |
30 (13) |
Harmonic | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | -64.1 | -51.2 | -29.4 | +0.0 | +36.2 | -62.7 | -15.2 | +37.2 | -47.3 | +13.4 | -63.6 |
Relative (%) | -45.4 | -36.3 | -20.9 | +0.0 | +25.7 | -44.4 | -10.7 | +26.4 | -33.5 | +9.5 | -45.0 | |
Steps (reduced) |
31 (14) |
32 (15) |
33 (16) |
34 (0) |
35 (1) |
35 (1) |
36 (2) |
37 (3) |
37 (3) |
38 (4) |
38 (4) |