5-odd-limit: Difference between revisions
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{{ | {{Odd-limit navigation|5}} | ||
[[File:5-odd-limit.png|480px|thumb|right|5-odd-limit intervals within an octave]] | |||
{{Odd-limit intro|5}} | |||
* [[1/1]] | * [[1/1]] | ||
| Line 7: | Line 8: | ||
* [[4/3]], [[3/2]] | * [[4/3]], [[3/2]] | ||
[[ | {| class="wikitable center-all right-2 left-5" | ||
[[Category: | ! Ratio | ||
! Size ([[cents|¢]]) | |||
! colspan="2" | [[Color name]] | |||
! Name | |||
|- | |||
| [[6/5]] | |||
| 315.641 | |||
| g3 | |||
| gu 3rd | |||
| minor third | |||
|- | |||
| [[5/4]] | |||
| 386.314 | |||
| y3 | |||
| yo 3rd | |||
| major third | |||
|- | |||
| [[8/5]] | |||
| 813.686 | |||
| g6 | |||
| gu 6th | |||
| minor sixth | |||
|- | |||
| [[5/3]] | |||
| 884.359 | |||
| y6 | |||
| yo 6th | |||
| major sixth | |||
|} | |||
The smallest [[equal division of the octave]] which is [[consistent]] in the 5-odd-limit is [[3edo]]. | |||
The one which is distinctly consistent in the same is [[9edo]]. | |||
The {{W|Natural density|density}} of edos consistent in the 5-odd-limit is 3/4. See below for proof. | |||
{{Proof | |||
| title = Proof for the density of edos consistent in the 5-odd-limit | |||
| contents = Let the error of harmonic 3 be ''A''. Let the error of harmonic 5 be ''B''. By the {{w|equidistribution theorem}}, the relative error of any individual interval is {{w|equidistribution|equidistributed}} from −50% to +50%, so we have the probability density functions {{nowrap| ''f''<sub>''A''</sub>(''x'') {{=}} 1 }} if {{nowrap| −1/2 ≤ ''x'' ≤ +1/2 }} and 0 otherwise, {{nowrap| ''f''<sub>''B''</sub>(''y'') {{=}} 1 }} if {{nowrap| −1/2 ≤ ''y'' ≤ +1/2 }} and 0 otherwise. | |||
An edo is consistent in the 5-odd-limit if the error {{nowrap| ''C'' {{=}} ''B'' − ''A'' }} of the only compound interval – 5/3 – falls into the range from −50% to +50%. | |||
It is easy to show the probability density function ''f''<sub>''C''</sub>(''z'') is the {{w|triangular distribution}} {{nowrap| 1 − {{!}}''z''{{!}} }} if {{nowrap| −1 ≤ ''z'' ≤ +1 }} and 0 otherwise. | |||
The density of edos consistent in the 5-odd-limit therefore equals ({{subsup|∫|−1/2|+1/2}} ''f''<sub>''C''</sub>(''z'')''dz'')/({{subsup|∫|−∞|+∞}} ''f''<sub>''C''</sub>(''z'')''dz''), which evaluates to 3/4. | |||
}} | |||
== See also == | |||
* [[5-limit]] ([[prime limit]]) | |||
* [[Diamond5]] – as a scale | |||
[[Category:5-odd-limit| ]] <!-- main article --> | |||