4afdo: Difference between revisions
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{{Infobox AFDO|steps=4}} | |||
[[File:4ado scale.wav|thumb]] | [[File:4ado scale.wav|thumb]] | ||
''' | |||
'''4afdo''' ([[AFDO|arithmetic division of the octave]]), or '''4odo''' ([[otonal division]] of the octave), divides the octave into four parts of 1/4 each. It is a superset of [[3afdo]] and a subset of [[5afdo]]. As a scale it may be known as [[Harmonic mode|mode 4 of the harmonic series]] or the [[Overtone scale #Over-n scales|Over-4]] scale. Because 4 is a power of 2, 4afdo corresponds to the 4th to 8th harmonics octave-reduced. The notes of 4afdo create a [[4:5:6:7|harmonic seventh chord]]. | |||
The smallest [[edo]]s that maintain 25% or lower relative error on all intervals of 4afdo are [[10edo]] and [[15edo]], though they are not very accurate. The next two edos, [[22edo]] and [[31edo]], are the smallest that approximate 4afdo with appreciable accuracy. | |||
== Intervals == | == Intervals == | ||
{| class="wikitable center-all" | {| class="wikitable center-all" | ||
|- | |||
! # | ! # | ||
! Cents | ! Cents | ||
! Ratio | ! Ratio | ||
! Decimal | |||
! Interval name | ! Interval name | ||
! Audio | |||
|- | |- | ||
| 0 | | 0 | ||
| 0 | | 0 | ||
| [[1/1]] | | [[1/1]] | ||
| 1.0000 | |||
| perfect unison | | perfect unison | ||
| | |||
|- | |- | ||
| 1 | | 1 | ||
| 386.3 | | 386.3 | ||
| [[5/4]] | | [[5/4]] | ||
| 1.2500 | |||
| just major third | | just major third | ||
| [[File:Jid_5_4_pluck_adu_dr220.mp3]] | |||
|- | |- | ||
| 2 | | 2 | ||
| 702.0 | | 702.0 | ||
| [[3/2]] | | [[3/2]] | ||
| 1.5000 | |||
| just perfect fifth | | just perfect fifth | ||
| [[File:Jid_3_2_pluck_adu_dr220.mp3]] | |||
|- | |- | ||
| 3 | | 3 | ||
| 968.8 | | 968.8 | ||
| [[7/4]] | | [[7/4]] | ||
| 1.7500 | |||
| harmonic seventh | | harmonic seventh | ||
| [[File:Jid_7_4_pluck_adu_dr220.mp3]] | |||
|- | |- | ||
| 4 | | 4 | ||
| 1200.0 | | 1200.0 | ||
| [[2/1]] | | [[2/1]] | ||
| 2.0000 | |||
| perfect octave | | perfect octave | ||
| [[File:Jid_2_1_pluck_adu_dr220.mp3]] | |||
|} | |} | ||