4afdo
4ado is the arithmetic equal division of the octave into four parts of 1/4 each. 4ado is perhaps the smallest ADO that contains useful intervals for harmony, containing the major third, perfect fifth, and harmonic seventh. It is just large enough to be usable as a scale.
Intervals
| # | Cents | Ratio | Interval name |
|---|---|---|---|
| 0 | 0 | 1/1 | perfect unison |
| 1 | 386.3 | 5/4 | just major third |
| 2 | 702.0 | 3/2 | just perfect fifth |
| 3 | 968.8 | 7/4 | harmonic seventh |
| 4 | 1200.0 | 2/1 | perfect octave |