70edo: Difference between revisions

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== Theory ==

This tuning was singled out by [[William Stoney]] in his article "Theoretical Possibilities for Equally Tempered Systems" (in the book [https://monoskop.org/images/c/c3/Lincoln_Harry_B_ed_The_Computer_and_Music_1970.pdf The Computer and Music]) as one of the six best systems of size 72 or smaller, along with [[72edo|72]], [[65edo|65]], [[58edo|58]], [[53edo|53]], and [[41edo|41]]. These other systems have had notice paid to them, but the same does not seem to be true of 70, which seems to have been ignored ever since, despite its excellent fifth, which is the 4th number in the convergent sequence to the [[~~Logarithmic approximants #Argent_temperament~~|silver ratio]], following [[29edo]], [[12edo]], and [[5edo]] and preceding [[169edo]]. ~~The~~ fifth 41\70 is the true center of the diatonic tuning spectrum, as it is the [[geometric mean]] of 3\[[5edo]] and 4\[[7edo]].

This tuning was singled out by [[William Stoney]] in his article "Theoretical Possibilities for Equally Tempered Systems" (in the book [https://monoskop.org/images/c/c3/Lincoln_Harry_B_ed_The_Computer_and_Music_1970.pdf The Computer and Music]) as one of the six best systems of size 72 or smaller, along with [[72edo|72]], [[65edo|65]], [[58edo|58]], [[53edo|53]], and [[41edo|41]]. These other systems have had notice paid to them, but the same does not seem to be true of 70, which seems to have been ignored ever since, despite its excellent perfect fifth, which is the 4th number in the convergent sequence to the [[Argent tuning|silver ratio]], following [[29edo]], [[12edo]], and [[5edo]] and preceding [[169edo]]. It is the last edo to have exactly one [[5L 2s|diatonic]] perfect fifth, and this perfect fifth, 41\70, is the true center of the diatonic tuning spectrum, as it is the [[geometric mean]] of [[5edo|3\5edo]] and [[7edo|4\7edo]].

The [[patent val]] for 70edo [[tempering out|tempers out]] [[2048/2025]], making it a [[diaschismic]] system. An alternative mapping is 70c, with a flat rather than a sharp major third, tempering out [[32805/32768]]. In the [[7-limit]], the patent val tempers out [[126/125]], [[2430/2401]] and [[5120/5103]], and provides the optimum patent val for the [[kumonga]] temperament. The 70c val tempers out [[50/49]], making it a tuning for [[doublewide]] even better than the optimal patent val. The 70cd val tempers out [[225/224]] and [[3125/3087]] instead. The alternative mapping begins to make more sense in the [[11-limit]] and higher, where the patent val tempers out [[99/98]] and [[121/120]] in the 11-limit, [[169/168]] and [[352/351]] in the [[13-limit]], and [[221/220]] in the [[17-limit]]. 70cd on the other hand, with flat 5 and 7, tempers out [[100/99]] and [[245/242]] in the 11-limit, [[105/104]] and [[196/195]] in the 13-limit, and [[154/153]] and [[170/169]] in the 17-limit. 70 also makes sense as a no-5 or -7 system, tempering out [[131769/131072]] in the 11-limit, [[352/351]] and [[2197/2187]] in the 13-limit, and [[289/288]] and [[1089/1088]] in the 17-limit.

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=== Subsets and supersets ===

Since 70 factors into {{factorization|70}}, 70edo has subset edos {{EDOs| 2, 5, 7, 10, 14, and 35 }}. 140edo, which doubles it, provides good correction for its approximation to harmonics 5 and 7.

== Intervals ==

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== Notation ==

=== Ups and downs notation ===

~~Using [[Helmholtz–Ellis]] accidentals,~~ 70edo can be notated using [[ups and downs notation|ups and downs]]:

70edo can be notated using [[ups and downs notation|ups and downs]]. Trup is equivalent to quudsharp, trudsharp is equivalent to quup, etc.

Alternatively, sharps and flats with arrows borrowed from [[Helmholtz–Ellis notation]] can be used:

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default [[File:70-EDO_Revo_Sagittal.svg]]

</imagemap>

== Approximation to JI ==

=== 15-odd-limit interval mappings ===

{{Q-odd-limit intervals|69.9|apx=val|header=none|tag=none|title=15-odd-limit intervals by 70cd val mapping}}

== Scales ==

=== Kukula's 2.3.13 70edo MOS ===

In July 2025, composer and theorist [[James Kukula]] created a 17-tone [[MOS scale]] for his piece in the [[Monthly Tunings]] project. The scale is generated by stacking the interval 33\70, 17 times, then [[octave reduction|octave reducing]] the result. It is designed to approximate the 2.3.13 [[subgroup]] very accurately. He discusses it in his blog post titled ''[https://interdependentscience.blogspot.com/2025/07/stepping-outside.html Stepping Outside]''.

; Subsets

* Kukula-Lambeth tridecimal neutral octatonic{{idiosyncratic}}: 8 13 8 12 8 9 8 4

* Kukula-Lambeth tridecimal neutral heptatonic{{idiosyncratic}}: 8 13 8 12 8 9 12

== Instruments ==

A [[Lumatone mapping for 70edo]] is available.

== Music ==

; [[Bryan Deister]]

* [https://www.youtube.com/shorts/I42JQ98WPZI ''microtonal improvisation in 70edo''] (2025)

* [https://www.youtube.com/shorts/gp42aya9TL0 ''Drift Away - Steven Universe (microtonal cover in 70edo)''] (2025)

* [https://www.youtube.com/watch?v=Uc0c-AYq-zM ''Waltz in 70edo''] (2025)

* [https://www.youtube.com/watch?v=-NEq3jKHjzs ''Improv in 70edo''] (2025)

* [https://www.youtube.com/shorts/ZDU75YabROE ''70edo prelude''] (2025)

; [[James Kukula]]

* [https://app.box.com/s/i9vvgcplpmksrm8rubz2h3asee2cnr26 ''piece from Stepping Outside''] (2025)

; [[Budjarn Lambeth]]

* [https://www.youtube.com/watch?v=dyEH-pP2dJU ''Improv in 70edo (Polymicrotonal 10edo+14edo Scale)''] (2025)

[[Category:Listen]]

@@ Line 3: / Line 3: @@
 == Theory ==
-This tuning was singled out by [[William Stoney]] in his article "Theoretical Possibilities for Equally Tempered Systems" (in the book [https://monoskop.org/images/c/c3/Lincoln_Harry_B_ed_The_Computer_and_Music_1970.pdf The Computer and Music]) as one of the six best systems of size 72 or smaller, along with [[72edo|72]], [[65edo|65]], [[58edo|58]], [[53edo|53]], and [[41edo|41]]. These other systems have had notice paid to them, but the same does not seem to be true of 70, which seems to have been ignored ever since, despite its excellent fifth, which is the 4th number in the convergent sequence to the [[Logarithmic approximants #Argent_temperament|silver ratio]], following [[29edo]], [[12edo]], and [[5edo]] and preceding [[169edo]]. The fifth 41\70 is the true center of the diatonic tuning spectrum, as it is the [[geometric mean]] of 3\[[5edo]] and 4\[[7edo]].
+This tuning was singled out by [[William Stoney]] in his article "Theoretical Possibilities for Equally Tempered Systems" (in the book [https://monoskop.org/images/c/c3/Lincoln_Harry_B_ed_The_Computer_and_Music_1970.pdf The Computer and Music]) as one of the six best systems of size 72 or smaller, along with [[72edo|72]], [[65edo|65]], [[58edo|58]], [[53edo|53]], and [[41edo|41]]. These other systems have had notice paid to them, but the same does not seem to be true of 70, which seems to have been ignored ever since, despite its excellent perfect fifth, which is the 4th number in the convergent sequence to the [[Argent tuning|silver ratio]], following [[29edo]], [[12edo]], and [[5edo]] and preceding [[169edo]]. It is the last edo to have exactly one [[5L 2s|diatonic]] perfect fifth, and this perfect fifth, 41\70, is the true center of the diatonic tuning spectrum, as it is the [[geometric mean]] of [[5edo|3\5edo]] and [[7edo|4\7edo]].
 The [[patent val]] for 70edo [[tempering out|tempers out]] [[2048/2025]], making it a [[diaschismic]] system. An alternative mapping is 70c, with a flat rather than a sharp major third, tempering out [[32805/32768]]. In the [[7-limit]], the patent val tempers out [[126/125]], [[2430/2401]] and [[5120/5103]], and provides the optimum patent val for the [[kumonga]] temperament. The 70c val tempers out [[50/49]], making it a tuning for [[doublewide]] even better than the optimal patent val. The 70cd val tempers out [[225/224]] and [[3125/3087]] instead. The alternative mapping begins to make more sense in the [[11-limit]] and higher, where the patent val tempers out [[99/98]] and [[121/120]] in the 11-limit, [[169/168]] and [[352/351]] in the [[13-limit]], and [[221/220]] in the [[17-limit]]. 70cd on the other hand, with flat 5 and 7, tempers out [[100/99]] and [[245/242]] in the 11-limit, [[105/104]] and [[196/195]] in the 13-limit, and [[154/153]] and [[170/169]] in the 17-limit. 70 also makes sense as a no-5 or -7 system, tempering out [[131769/131072]] in the 11-limit, [[352/351]] and [[2197/2187]] in the 13-limit, and [[289/288]] and [[1089/1088]] in the 17-limit.
@@ Line 14: / Line 14: @@
 === Subsets and supersets ===
 Since 70 factors into {{factorization|70}}, 70edo has subset edos {{EDOs| 2, 5, 7, 10, 14, and 35 }}. 140edo, which doubles it, provides good correction for its approximation to harmonics 5 and 7.
 == Intervals ==
@@ Line 21: / Line 21: @@
 == Notation ==
 === Ups and downs notation ===
-Using [[Helmholtz–Ellis]] accidentals, 70edo can be notated using [[ups and downs notation|ups and downs]]:
+edo can be notated using [[ups and downs notation|ups and downs]]. Trup is equivalent to quudsharp, trudsharp is equivalent to quup, etc.
+{{Sharpness-sharp7a}}
+Alternatively, sharps and flats with arrows borrowed from [[Helmholtz–Ellis notation]] can be used:
 {{Sharpness-sharp7}}
@@ Line 48: / Line 52: @@
 default [[File:70-EDO_Revo_Sagittal.svg]]
 </imagemap>
+== Approximation to JI ==
+=== 15-odd-limit interval mappings ===
+{{Q-odd-limit intervals|70}}
+{{Q-odd-limit intervals|69.9|apx=val|header=none|tag=none|title=15-odd-limit intervals by 70cd val mapping}}
+== Scales ==
+=== Kukula's 2.3.13 70edo MOS ===
+In July 2025, composer and theorist [[James Kukula]] created a 17-tone [[MOS scale]] for his piece in the [[Monthly Tunings]] project. The scale is generated by stacking the interval 33\70, 17 times, then [[octave reduction|octave reducing]] the result. It is designed to approximate the 2.3.13 [[subgroup]] very accurately. He discusses it in his blog post titled ''[https://interdependentscience.blogspot.com/2025/07/stepping-outside.html Stepping Outside]''.
+; Subsets
+* Kukula-Lambeth tridecimal neutral octatonic{{idiosyncratic}}: 8 13 8 12 8 9 8 4
+* Kukula-Lambeth tridecimal neutral heptatonic{{idiosyncratic}}: 8 13 8 12 8 9 12
+== Instruments ==
+A [[Lumatone mapping for 70edo]] is available.
+== Music ==
+; [[Bryan Deister]]
+* [https://www.youtube.com/shorts/I42JQ98WPZI ''microtonal improvisation in 70edo''] (2025)
+* [https://www.youtube.com/shorts/gp42aya9TL0 ''Drift Away - Steven Universe (microtonal cover in 70edo)''] (2025)
+* [https://www.youtube.com/watch?v=Uc0c-AYq-zM ''Waltz in 70edo''] (2025)
+* [https://www.youtube.com/watch?v=-NEq3jKHjzs ''Improv in 70edo''] (2025)
+* [https://www.youtube.com/shorts/ZDU75YabROE ''70edo prelude''] (2025)
+; [[James Kukula]]
+* [https://app.box.com/s/i9vvgcplpmksrm8rubz2h3asee2cnr26 ''piece from Stepping Outside''] (2025)
+; [[Budjarn Lambeth]]
+* [https://www.youtube.com/watch?v=dyEH-pP2dJU ''Improv in 70edo (Polymicrotonal 10edo+14edo Scale)''] (2025)
+[[Category:Listen]]