17edo

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Prime factorization 17 (prime)
Step size 70.5882 ¢ 
Fifth 10\17 (705.882 ¢)
(semiconvergent)
Semitones (A1:m2) 2:1 (141.2 ¢ : 70.59 ¢)
Consistency limit 3
Distinct consistency limit 3

17 equal divisions of the octave (abbreviated 17edo or 17ed2), also called 17-tone equal temperament (17tet) or 17 equal temperament (17et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 17 equal parts of about 70.6 ¢ each. Each step represents a frequency ratio of 21/17, or the 17th root of 2.

English Wikipedia has an article on:

Theory

17edo is the next smallest edo to have a diatonic perfect fifth after 12edo, and is quite popular for that reason. The perfect fifth is around 4 cents sharp of just, and around 6 cents sharp of 12edo's, lending itself to a diatonic scale with more constrasting large and small steps, so it can be seen as a tuning that emphasizes the hardness of Pythagorean tuning rather than mellowing it out as in meantone. It completely misses harmonic 5, with 5/4 and 6/5 both being about halfway between its steps, but it approximates harmonics 7, 11, 13, and 23 acceptably, with a sharp tuning for all of them. It can thus be treated as a temperament of the 2.3.25.7.11.13.23 subgroup or any of its subsets, where it is quite accurate for its size.

A notable comma it tempers out is 64/63, which equates the harmonic seventh 7/4 with the pythagorean minor seventh 16/9, while its patent val does not temper out 81/80. This makes 17edo by default a superpythagorean system rather than a meantone one, being very close to 1/7-comma superpyth. Other commas it tempers out can be found in the #Commas section, each of which has its own effect on the structure of 17edo. If one wants to approximate JI with prime 5, then 17edo would not be the best option, and it would be better to use other systems like 19edo, 22edo, 27edo, or 31edo instead. That said, the 17c val (written using wart notation) does temper out 81/80 (while improving consistency as shown below in #Approximation to JI), while still tempering out 64/63, thus placing it on the meantone spectrum with the dominant extension.

As a means of extending harmony

The diatonic major triad, which is 0–6–10 steps, is quite dissonant compared to 4:5:6, as the major third is over 37 cents sharp from the traditional 5/4, and is instead closer to 9/7 or 14/11. Instead, a different construction based on the 2.3.7 subgroup follows naturally from its support of superpyth, and may be preferred. Such chords include the tetrads 6:7:8:9 and its utonal inverse, realized in 17edo as 0–4–7–10 and 0–3–6–10, respectively, in addition to the sus2-4 chord, realized as 0–3–7–10. Possible chromatic alterations include but are not limited to an approximation of 12:13:16:18, 0–2–7–10, and an approximation of 8:9:11:12, 0–3–8–10. It is important to note that the chromatic semitone in 17edo is 2 steps, rather than 1 step as in 12edo or 19edo. Similarly, the fourth-spanning triad 6:7:8 and its inverse can be used, with their wide voicing realized in 17edo as 0–14–27 and 0–13–27, respectively. Extensions of these chords include 0–12–14–27, representing 8:13:14:24, and 0–13–15–27, representing 7:12:13:21.

Since the intervals of the 2.3.7-subgroup cluster around 5edo, a pentatonic system of interval classification may be preferred over the heptatonic one, with 7/6 becoming a major interval and 8/7~9/8 becoming a minor one.

Of course, scales generated by the perfect fifth are not the only scales 17edo contains. Another type of scale is neutral third scales, which are generated by half a fifth (5\17), and take the mos patterns 4L 3s (mosh) and 7L 3s (dicoid). Other notable scales include that of bleu and glacier (generated by 2\17), and skwares (generated by 6\17). Non-mos scales also exist; a more complete list can be found in the #Scales section.

Because the 5th harmonic is not well approximated, using timbres with attenuated 5th harmonics (and its multiples) may reduce audible beating.

Odd harmonics

Approximation of odd harmonics in 17edo
Harmonic 3 5 7 9 11 13 15 17 19 21 23
Error Absolute (¢) +3.9 -33.4 +19.4 +7.9 +13.4 +6.5 -29.4 -34.4 -15.2 +23.3 +7.0
Relative (%) +5.6 -47.3 +27.5 +11.1 +19.0 +9.3 -41.7 -48.7 -21.5 +33.1 +9.9
Steps
(reduced)
27
(10)
39
(5)
48
(14)
54
(3)
59
(8)
63
(12)
66
(15)
69
(1)
72
(4)
75
(7)
77
(9)
Approximation of odd harmonics in 17edo (continued)
Harmonic 25 27 29 31 33 35 37 39 41 43 45 47
Error Absolute (¢) +3.8 +11.8 +29.2 -15.6 +17.3 -14.0 +31.0 +10.5 -5.5 -17.4 -25.5 -30.2
Relative (%) +5.4 +16.7 +41.4 -22.1 +24.5 -19.8 +43.9 +14.8 -7.8 -24.7 -36.2 -42.8
Steps
(reduced)
79
(11)
81
(13)
83
(15)
84
(16)
86
(1)
87
(2)
89
(4)
90
(5)
91
(6)
92
(7)
93
(8)
94
(9)

Subsets and supersets

17edo is the seventh prime edo, following 13edo and coming before 19edo. It does not contain any nontrivial subset edos, though it contains 17ed4 and 17ed8. 17ed8, built by taking every third step of 17edo, is a system where all odd harmonics up to the 21st are mapped exactly as in 17edo, except for the 11th. Beyond that, the 27th, 31st, 35th, and 39th harmonics are likewise mapped identically.

34edo, which doubles 17edo, provides a great correction to harmonics 5 and 17; while 68edo, which quadruples it, provides additionally the primes 7, 19, and 31.

Intervals

# Cents Approximate ratios[note 1] Circle-of-fifths notation[note 2] Ups and downs notation
(EUs: vvA1 and ^d2)
SKULO notation (U = 1)
0 0.0 1/1 Unison D unison P1 D unison P1 D
1 70.6 24/23, 25/24, 26/25, 27/26, 28/27 Minor 2nd
(Semiaugmented 1sn)
Eb
(Dt)
up unison,
minor 2nd
^1, m2 Eb uber unison,
minor 2nd
U1, m2 UD, Eb
2 141.2 12/11, 13/12, 14/13, 25/23 Augmented 1sn
(Neutral 2nd)
D#
(Ed)
augmented 1sn,
mid 2nd
A1, ~2 vE neutral 2nd N2 UEb, uE
3 211.8 8/7, 9/8, 17/15, 25/22, 26/23 Major 2nd E major 2nd M2 E major 2nd M2 E
4 282.4 7/6, 13/11, 20/17 Minor 3rd F minor 3rd m3 F minor 3rd m3 F
5 352.9 11/9, 27/22, 16/13, 39/32 Diminished 4th
(Neutral 3rd)
Gb
(Ft)
mid 3rd ~3 ^F neutral 3rd N3 UF, uF#
6 423.5 9/7, 14/11, 23/18, 32/25, 51/40 Major 3rd
(Semidiminished 4th)
F#
(Gd)
major 3rd M3 F# major 3rd M3 F#
7 494.1 4/3, 21/16, 85/64 Perfect 4th G perfect 4th P4 G perfect 4th P4 G
8 564.7 11/8, 18/13, 25/18, 32/23 Diminished 5th
(Semiaugmented 4th)
Ab
(Gt)
mid 4th,
diminished 5th
~4, d5 ^G, Ab uber 4th/
neutral 4th
U4/N4 UG
9 635.3 13/9, 16/11, 23/16, 36/25 Augmented 4th
(Semidiminished 5th)
G#
(Ad)
augmented 4th,
mid 5th
A4, ~5 G#, vA unter 5th/
neutral 5th
u5/N5 uA
10 705.9 3/2, 32/21, 128/85 Perfect 5th A perfect 5th P5 A perfect 5th P5 A
11 776.5 11/7, 14/9, 25/16, 36/23, 80/51 Minor 6th
(Semiaugmented 5th)
Bb
(At)
minor 6th m6 Bb minor 6th m6 Bb
12 847.1 13/8, 18/11, 44/27, 64/39 Augmented 5th
(Neutral 6th)
A#
(Bd)
mid 6th ~6 vB neutral 6th N6 UBb, uB
13 917.6 12/7, 17/10, 22/13 Major 6th B major 6th M6 B major 6th M6 B
14 988.2 7/4, 16/9, 23/13, 30/17, 44/25 Minor 7th C minor 7th m7 C minor 7th m7 C
15 1058.8 11/6, 13/7, 24/13, 46/25 Diminished 8ve
(Neutral 7th)
Db
(Ct)
mid 7th ~7 ^C neutral 7th N7 UC, uC#
16 1129.4 23/12, 25/13, 27/14, 48/25, 52/27 Major 7th
(Semidiminished 8ve)
C#
(Dd)
major 7th,
down 8ve
M7, v8 C# major 7th,
unter octave
M7, u8 C#, uD
17 1200.0 2/1 Octave D octave P8 D octave P8 D
  1. Based on treating 17edo as a 2.3.25.7.11.13.85.23 subgroup temperament; other approaches are also possible.
  2. Half-sharps and half-flats (denoted "t" and "d", respectively) can be used to alter the note by a single step, since sharps and flats each span two edosteps. Using half-sharps and half-flats may be preferable for compatibility with the ups-and-downs notation in 34edo, in which an up or down respectively constitute a quarter-sharp or quarter-flat.

Interval quality and chord names in color notation

Combining ups and downs notation with color notation, qualities can be loosely associated with colors:

Quality Color Monzo format Examples
minor zo (a, b, 0, 1) 7/6, 7/4
fourthward wa (a, b), b < -1 32/27, 16/9
mid ilo (a, b, 0, 0, 1) 11/9, 11/6
lu (a, b, 0, 0, -1) 12/11, 18/11
major fifthward wa (a, b), b > 1 9/8, 27/16
ru (a, b, 0, -1) 9/7, 12/7

All 17edo chords can be named using ups and downs. Here are the zo, ilo and ru triads:

Color of the 3rd JI chord Notes as edosteps Notes of C chord Written name Spoken name
zo 6:7:9 0-4-10 C Eb G Cm C minor
ilo 18:22:27 0-5-10 C vE G C~ C mid
ru 14:18:21 0-6-10 C E G C C major or C

Alterations are always enclosed in parentheses, additions never are. An up, down or mid immediately after the chord root affects the 3rd, 6th, 7th, and/or the 11th (every other note of a stacked-3rds chord 6-1-3-5-7-9-11-13).

0-4-9 = C Eb vG = Cm(v5) = C minor down-five

0-5-9 = C vE vG = C~(v5) = C mid down-five

0-6-11 = C E ^G = C(^5) = C up-five

0-4-10-14 = C Eb G Bb = Cm7 = C minor seven

0-5-10-14 = C vE G Bb = C~,7 = C mid add seven

0-6-10-15 = C E G vB = C,~7 = C add mid-seven

0-5-10-15 = C vE G vB = C~7 = C mid-seven

For a more complete list, see Ups and downs notation #Chords and chord progressions.

Notation

Ups and downs notation

Spoken as up, sharp, upsharp, etc. Note that up can be respelled as downsharp. The gamut runs D, ^D/Eb, D#/vE, E, F etc.

Step offset 0 1 2 3 4 5
Sharp symbol   
  
  
  
  
Flat symbol
  
  
  
  

Quarter tone notation

Since a sharp raises by 2 steps, 17edo can be notated using quarter-tone accidentals.

Step offset −4 −3 −2 −1 0 +1 +2 +3 +4
Symbol

Sagittal notation

This notation uses the same sagittal sequence as edos 24, 31, and 38, and is a subset of the notation for 34edo.

Evo and Revo flavors

17-EDO__Sagittal.svg

Alternative Evo flavor

17-EDO_Alternative_Evo_Sagittal.svg

Evo-SZ flavor

17-EDO_Evo-SZ_Sagittal.svg

Because it contains no Sagittal symbols, this Evo-SZ Sagittal notation is identical to the Stein-Zimmerman notation.

Sagittal songbook diagram

From the appendix to The Sagittal Songbook by Jacob A. Barton, a diagram of how to notate 17edo in the Revo flavor of Sagittal:

3L 4s (mosh) notation

The notation of Neutral[7]. The generator is the perfect 3rd. Notes are denoted as sLsLsLs = DEFGABCD, and raising and lowering by a chroma (L − s), 1 edostep in this instance, is denoted by ♯ and ♭.

# Cents Note Name Associated ratios
0 0.0 D Perfect 1sn 1/1
1 70.6 D# Augmented 1sn 33/32
2 141.2 Eb Minor 2nd 12/11
3 211.8 E Major 2nd 9/8
4 282.4 Fb Diminished 3rd 32/27
5 352.9 F Perfect 3rd 11/9, 27/22
6 423.5 F# Augmented 3rd 81/64
7 494.1 G Minor 4th 4/3
8 564.7 G# Major 4th 11/8
9 635.3 Ab Minor 5th 16/11
10 705.9 A Major 5th 3/2
11 776.5 Bb Diminished 6th 128/81
12 847.1 B Perfect 6th 18/11, 44/27
13 917.6 B# Augmented 6th 27/16
14 988.2 Cb Minor 7th 16/9
15 1058.8 C Major 7th 11/6
16 1129.4 Db Diminished 8ve 64/33
17 1200.0 D Perfect 8ve 2/1

Approximation to JI

15-odd-limit interval mappings

The following tables show how 15-odd-limit intervals are represented in 17edo. Prime harmonics are in bold; inconsistent intervals are in italics.

15-odd-limit intervals in 17edo (direct approximation, even if inconsistent)
Interval and complement Error (abs, ¢) Error (rel, %)
1/1, 2/1 0.000 0.0
13/9, 18/13 1.324 1.9
13/12, 24/13 2.604 3.7
3/2, 4/3 3.927 5.6
11/9, 18/11 5.533 7.8
11/7, 14/11 6.021 8.5
13/8, 16/13 6.531 9.3
13/11, 22/13 6.857 9.7
9/8, 16/9 7.855 11.1
11/6, 12/11 9.461 13.4
9/7, 14/9 11.555 16.4
13/7, 14/13 12.878 18.2
11/8, 16/11 13.388 19.0
7/6, 12/7 15.482 21.9
7/5, 10/7 17.806 25.2
7/4, 8/7 19.409 27.5
15/14, 28/15 21.734 30.8
11/10, 20/11 23.828 33.8
15/11, 22/15 27.755 39.3
9/5, 10/9 29.361 41.6
15/8, 16/15 29.445 41.7
13/10, 20/13 30.685 43.5
5/3, 6/5 33.288 47.2
5/4, 8/5 33.373 47.3
15/13, 26/15 34.612 49.0
15-odd-limit intervals in 17edo (patent val mapping)
Interval and complement Error (abs, ¢) Error (rel, %)
1/1, 2/1 0.000 0.0
13/9, 18/13 1.324 1.9
13/12, 24/13 2.604 3.7
3/2, 4/3 3.927 5.6
11/9, 18/11 5.533 7.8
11/7, 14/11 6.021 8.5
13/8, 16/13 6.531 9.3
13/11, 22/13 6.857 9.7
9/8, 16/9 7.855 11.1
11/6, 12/11 9.461 13.4
9/7, 14/9 11.555 16.4
13/7, 14/13 12.878 18.2
11/8, 16/11 13.388 19.0
7/6, 12/7 15.482 21.9
7/4, 8/7 19.409 27.5
15/8, 16/15 29.445 41.7
5/4, 8/5 33.373 47.3
15/13, 26/15 35.976 51.0
5/3, 6/5 37.300 52.8
13/10, 20/13 39.904 56.5
9/5, 10/9 41.227 58.4
15/11, 22/15 42.833 60.7
11/10, 20/11 46.760 66.2
15/14, 28/15 48.855 69.2
7/5, 10/7 52.782 74.8
15-odd-limit intervals by 17c val mapping
Interval and complement Error (abs, ¢) Error (rel, %)
1/1, 2/1 0.000 0.0
13/9, 18/13 1.324 1.9
13/12, 24/13 2.604 3.7
3/2, 4/3 3.927 5.6
11/9, 18/11 5.533 7.8
11/7, 14/11 6.021 8.5
13/8, 16/13 6.531 9.3
13/11, 22/13 6.857 9.7
9/8, 16/9 7.855 11.1
11/6, 12/11 9.461 13.4
9/7, 14/9 11.555 16.4
13/7, 14/13 12.878 18.2
11/8, 16/11 13.388 19.0
7/6, 12/7 15.482 21.9
7/5, 10/7 17.806 25.2
7/4, 8/7 19.409 27.5
15/14, 28/15 21.734 30.8
11/10, 20/11 23.828 33.8
15/11, 22/15 27.755 39.3
9/5, 10/9 29.361 41.6
13/10, 20/13 30.685 43.5
5/3, 6/5 33.288 47.2
15/13, 26/15 34.612 49.0
5/4, 8/5 37.216 52.7
15/8, 16/15 41.143 58.3

Selected 13-limit intervals

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Tuning by ear

17edo is very close to a circle of seventeen 25/24 chromatic semitones: (25/24)17 is only 1.43131 cents sharp of an octave. This means that if you can tune seventeen 25/24's accurately (by say, tuning 5/4 up, 3/2 down and 5/4 up, taking care to minimize the error at each step), you have a shot at approximating 17edo within melodic just noticeable difference.

Regular temperament properties

Subgroup Comma list Mapping Optimal
8ve stretch (¢)
Tuning error
Absolute (¢) Relative (%)
2.3 [27 -17 [17 27]] −1.24 1.24 1.76
2.3.7 64/63, 17496/16807 [17 27 48]] −3.13 2.85 4.05
2.3.7.11 64/63, 99/98, 243/242 [17 27 48 59]] −3.31 2.49 3.54
2.3.7.11.13 64/63, 78/77, 99/98, 144/143 [17 27 48 59 63]] −3.00 2.31 3.28
  • 17et is lower in relative error than any previous equal temperaments in the no-5 11- and 13-limit. The next equal temperaments doing better in these subgroups are 41 and 207, respectively.

Uniform maps

13-limit uniform maps between 16.8 and 17.2
Min. size Max. size Wart notation Map
16.7196 16.8899 17def 17 27 39 47 58 62]
16.8899 16.9103 17de 17 27 39 47 58 63]
16.9103 16.9198 17d 17 27 39 47 59 63]
16.9198 17.0117 17 17 27 39 48 59 63]
17.0117 17.1601 17c 17 27 40 48 59 63]
17.1601 17.1994 17cff 17 27 40 48 59 64]
17.1994 17.2760 17ceeff 17 27 40 48 60 64]

Commas

17et tempers out the following commas. (Note: This assumes patent val 17 27 39 48 59 63 69 72 77], cent values ​​rounded to 1/100 of a cent.)

Prime
limit
Ratio[note 1] Monzo Cents Color name Name
3 (18 digits) [27 -17 66.76 Sasawa Gothic comma
5 25/24 [-3 -1 2 70.76 Yoyo Dicot comma
5 32805/32768 [-15 8 1 1.95 Layo Schisma
7 64/63 [6 -2 0 -1 27.26 Ru Septimal comma
7 525/512 [-9 1 2 1 43.41 Lazoyoyo Avicennma
7 245/243 [0 -5 1 2 14.19 Zozoyo Sensamagic comma
7 1728/1715 [6 3 -1 -3 13.07 Triru-agu Orwellisma
7 17496/16807 [3 7 0 -5 69.56 Quinru Bleu comma
7 19683/19208 [-3 9 0 -4 42.29 Laquadru Skwares comma
7 (12 digits) [-6 -8 2 5 1.12 Quinzo-ayoyo Wizma
11 45/44 [-2 2 1 0 -1 38.91 Luyo Cake comma
11 99/98 [-1 2 0 -2 1 17.58 Loruru Mothwellsma
11 896/891 [7 -4 0 1 -1 9.69 Saluzo Pentacircle comma
11 243/242 [-1 5 0 0 -2 7.14 Lulu Rastma, neutral thirds comma
11 385/384 [-7 -1 1 1 1 4.50 Lozoyo Keenanisma
13 40/39 [3 -1 1 0 0 -1 43.83 Thuyo Unintendo comma
13 65/64 [-6 0 1 0 0 1 26.84 Thoyo Wilsorma
13 78/77 [1 1 0 -1 -1 1 22.34 Tholuru Negustma
13 144/143 [4 2 0 0 -1 -1 12.06 Thulu Grossma
13 169/168 [-3 -1 0 -1 0 2 10.27 Thothoru Buzurgisma, dhanvantarisma
13 352/351 [5 -3 0 0 1 -1⟩ 4.93 Thulo Major minthma
13 364/363 [2 -1 0 1 -2 1 4.76 Tholuluzo Minor minthma
13 512/507 [9 -1 0 0 0 -2 16.99 Thuthu Tridecimal neutral thirds comma
13 1352/1331 [3 0 0 0 -3 2 27.10 Bithotrilu Lovecraft comma
13 2197/2187 [0 -7 0 0 0 3 7.90 Satritho Threedie
23 162/161 [1 4 0 -1 0 0 0 0 -1 10.72 Twethuru Minor kirnbergerisma
23 208/207 [4 -2 0 0 0 1 0 0 -1 8.34 Twethutho Vicetone comma
23 253/252 [-2 -2 0 -1 1 0 0 0 1 6.86 Twetholoru Middle neutravicema
23 529/528 [-4 -1 0 0 -1 0 0 0 2 3.28 Bitwetho-alu Preziosisma
23 736/729 [5 -6 0 0 0 0 0 0 1 16.54 Satwetho 23-limit Tenney/Cage comma (HEJI)
  1. Ratios longer than 10 digits are presented by placeholders with informative hints.

Note that due to the inaccurate prime 5, the rather large commas 25/24, 525/512, 45/44, and 40/39 are all tempered out by 17edo's patent val.

Rank-2 temperaments

Table of rank-2 temperaments by generator
Periods
per 8ve
Generator Cents Associated
ratio
Temperament
1 2\17 141.18 13/12 Bleu / progression (17c) / glacier
1 3\17 211.76 8/7~9/8 Machine
1 3\17 211.76 26/23 Shoal (trivial tuning)
1 4\17 282.35 13/11 Huxley / lovecraft / subklei (17c)
1 5\17 352.94 11/9 Suhajira / neutrominant (17c) / beatles (17c) / dichotic (17)
Hemif / mohamaq (17c) / salsa (17)
1 6\17 423.53 9/7 Skwares / squares (17c) / sentinel (17) / sidi (17)
1 7\17 494.12 4/3 Archy / supra / quasisuper (17c) / dominant (17c) / superpyth (17) / schism (17)
Fiventeen
1 8\17 564.71 7/5 Lee / liese (17c) / pycnic (17)
Progress (17c)

Octave stretch or compression

17edo's approximations of harmonics 3, 7, 11, and 13 are all tempered sharp, so 17edo adapts well to slightly compressing the octave, if that is acceptable. 44ed6, 27edt and 56zpi are good demonstrations of this, where the octaves are flattened by about 1.5, 2.5 cents and 3 cents respectively.

Scales

MOS scales

Well temperaments

Instruments

Fretted String Instruments

17P1050829r.JPG

  • 17edo soprano Harmony ukulele with a 3D printed fretboard - conversion by Tristan Bay

Keyboards

Lumatone mappings for 17edo are available.

The Striso Board can be tuned in many ways, but as it has 17 notes per octave and is organised in a circle of fifths based layout, it works particularly well with 17edo, letting you play far wider stretches of notes than a standard keyboard.

It is possible to rebuild some standard MIDI keyboards to have 17 note per octave by combining parts from multiple keyboards, as with the finished product shown in the following videos by Stephen Weigel and Chris Vaisvil:

Music

See also: Category:17edo tracks
YouTube playlist of 17edo pieces
YouTube videos tagged with 17edo
Compositions from the Seventeen Tone Piano Project

Introductory Materials