42edo: Difference between revisions

BudjarnLambeth (talk | contribs)
BudjarnLambeth (talk | contribs)
Stretch compression
 
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{{Harmonics in equal|42}}
{{Harmonics in equal|42}}
=== Octave stretch ===
42edo’s inaccurate 3rd and 5th harmonics can be greatly improved through [[stretched and compressed tuning|stretching or compressing]] octaves. Both approaches work about equally well but in opposite directions, giving two quite different flavors of tuning to play with.
The following table compares three stretched tunings of 42edo:
{| class="wikitable mw-collapsible mw-collapsed"
|-
! Tuning
! [[42ed257/128]]
! [[11ed6/5]]
! [[zpi|189zpi]]
! [[42edo]]
|-
! Steps / octave
| ~41.77
| ~41.81
| ~41.83
| 42.00
|-
! Approximation<br>of harmonics
| great: 5<br>good: 2, 3, 7 <br>okay: <br>bad: 11, 13
| great: 5<br>good: 2, 3 <br>okay: 7, 11, 13 <br>bad:
| great: 5<br>good: 2, 13 <br>okay: 3, 11 <br>bad: 7
| great: 2, 7<br>good: <br>okay: 11 <br>bad: 3, 5, 13
|-
| colspan="5" | <span style="font-size: 0.75em;"><div style="text-align: center;">''“great” = 0-13% relative error • “good” = 13-27% • “okay” = 27-40% • “bad” = 40-50%''</div></span>
|}
The following table compares three compressed tunings of 42edo:
{| class="wikitable mw-collapsible mw-collapsed"
|-
! Tuning
! [[42edo]]
! [[Equal-step tuning|34ed7/4]]
! [[191zpi]]
! [[AS|AS123/121]]
|-
! Steps / octave
| 42.00
| ~42.10
| ~42.19
| ~42.24
|-
! Approximation <br>of harmonics
| great: 2, 7 <br>good: <br>okay: 11 <br>bad: 3, 5, 13
| great: 2 <br>good: 5, 7, 13 <br>okay: 3, 11 <br>bad:
| great: 5, 11, 13 <br>good: 2, 3 <br>okay: <br>bad: 7
| great: 3, 5, 11 <br>good: 2 <br>okay: 13 <br>bad: 7
|-
| colspan="5" | <span style="font-size: 0.75em;"><div style="text-align: center;">''“great” = 0-13% relative error • “good” = 13-27% • “okay” = 27-40% • “bad” = 40-50%''</div></span>
|}


=== Subsets and supersets ===
=== Subsets and supersets ===
Line 425: Line 372:
| 11.42
| 11.42
|}
|}
== Octave stretch or compression ==
42edo’s inaccurate 3rd and 5th harmonics can be greatly improved through [[stretched and compressed tuning|stretching or compressing]] octaves. Both approaches work about equally well but in opposite directions, giving two quite different flavors of tuning to play with.
What follows is a comparison of stretched- and compressed-octave 42edo tunings.
; [[ed6|108ed6]]
* Octave size: 1206.3{{c}}
Stretching the octave of 42edo by around 6{{c}} results in improved primes 3, 5 and 13, but worse primes 2, 7 and 11. This approximates all harmonics up to 16 within 13.3{{c}}. The tuning 108ed6 does this. So does the tuning [[ed5|97ed5]] whose octave differs by only 0.1{{c}}.
{{Harmonics in equal|108|6|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 108ed6}}
{{Harmonics in equal|108|6|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 108ed6 (continued)}}
; [[zpi|189zpi]]
* Step size: 28.689{{c}}, octave size: 1204.9{{c}}
Stretching the octave of 42edo by around 5{{c}} results in improved primes 3, 5 and 13, but worse primes 2 and 11. This approximates all harmonics up to 16 within 13.9{{c}}. The tuning 189zpi does this.
{{Harmonics in cet|28.689|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 189zpi}}
{{Harmonics in cet|28.689|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 189zpi (continued)}}
; [[ed12|150ed12]]
* Octave size: 1204.5{{c}}
Stretcing the octave of 42edo by around 4.5{{c}} results in improved primes 3, 5, 11 and 13, but worse primes 2 and 7. This approximates all harmonics up to 16 within 13.6{{c}}. The tuning 150ed12 does this.
{{Harmonics in equal|150|12|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 150ed12}}
{{Harmonics in equal|150|12|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 150ed12 (continued)}}
; [[equal tuning|145ed11]]
* Octave size: 1202.5{{c}}
Stretching the octave of 42edo by around 2.5{{c}} results in improved primes 5, 11 and 13, but worse primes 2 and 7. This approximates all harmonics up to 16 within 11.9{{c}}. The tuning 145ed11 does this.
{{Harmonics in equal|145|11|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 145ed11}}
{{Harmonics in equal|145|11|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 145ed11 (continued)}}
; 42edo
* Step size: 28.571{{c}}, octave size: 1200.0{{c}}
Pure-octaves 42edo approximates all harmonics up to 16 within 13.7{{c}}. The tuning [[zpi|190zpi]] is almost exactly the same as pure-octaves 42edo, its octave differing by less than 0.05{{c}}.
{{Harmonics in equal|42|2|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 42edo}}
{{Harmonics in equal|42|2|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 42edo (continued)}}
; [[ed7|118ed7]]
* Step size: Octave size: 1199.1{{c}}
Compressing the octave of 42edo by around 1{{c}} results in improved primes 3, 5 and 7, but worse primes 2, 11 and 13. This approximates all harmonics up to 16 within 13.2{{c}}. The tuning 118ed7 does this.
{{Harmonics in equal|118|7|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 118ed7}}
{{Harmonics in equal|118|7|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 118ed7 (continued)}}
; [[WE|42et, 13-limit WE tuning]]
* Step size: 28.534{{c}}, octave size: 1198.4{{c}}
Compressing the octave of 42edo by around 1.5{{c}} results in improved primes 3, 5, 7 and 13, but worse primes 2 and 11. This approximates all harmonics up to 16 within 13.9{{c}}. Its 13-limit WE tuning and 13-limit [[TE]] tuning both do this.
Of the tunings discussed in this section, 13-limit WE and TE are the only ones to approximate all harmonics up to 10 within 10 cents, making them a good all-round choice.
{{Harmonics in cet|28.534|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 42et, 13-limit WE tuning}}
{{Harmonics in cet|28.534|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 42et, 13-limit WE tuning (continued)}}
; [[ed12|151ed12]]
* Step size: Octave size: 1196.6{{c}}
Compressing the octave of 42edo by around 3.5{{c}} results in improved primes 3, 5, 11 and 13, but worse primes 2 and 7. This approximates all harmonics up to 16 within 13.7{{c}}. The tuning 151ed12 does this. So do the 7-limit [[WE]] and [[TE]] tunings of 42et, whose octaves are within 0.3{{c}} of 151ed12.
{{Harmonics in equal|151|12|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 151ed12}}
{{Harmonics in equal|151|12|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 151ed12 (continued)}}
; [[ed6|109ed6]]
* Octave size: 1195.2{{c}}
Compressing the octave of 42edo by around 5{{c}} results in improved primes 3, 5, 11 and 13, but worse primes 2 and 7. This approximates all harmonics up to 16 within 14.2{{c}}. The tuning 109ed6 does this.
{{Harmonics in equal|109|6|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 109ed6}}
{{Harmonics in equal|109|6|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 109ed6 (continued)}}
; [[zpi|191zpi]]
* Step size: 28.444{{c}}, octave size: 1194.6{{c}}
Compressing the octave of 42edo by around 5.5{{c}} results in improved primes 3, 5, 11 and 13, but worse primes 2 and 7. This approximates all harmonics up to 16 within 12.4{{c}}. The tuning 191zpi does this.
{{Harmonics in cet|28.444|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 191zpi}}
{{Harmonics in cet|28.444|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 191zpi (continued)}}
; [[67edt]]
* Step size: 28.387{{c}}, octave size: 1192.3{{c}}
Compressing the octave of 42edo by around 7.5{{c}} results in improved primes 3, 5 and 11, but worse primes 2 and 7. This approximates all harmonics up to 16 within 12.9{{c}}. The tuning 67edt does this.
{{Harmonics in equal|67|3|1|intervals=integer|columns=11|collapsed=true|title=Approximation of harmonics in 67edt}}
{{Harmonics in equal|67|3|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 67edt (continued)}}


== Scales ==
== Scales ==