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. Because 4 is a power of 2, 4ado corresponds to the 1st to 4th harmonics octave-reduced.
Intervals
| # | Cents | Ratio | Interval name | Audio |
|---|---|---|---|---|
| 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 |