4ado is the arithmetic equal division of the octave into four parts of 1/4 each. Because 4 is a power of 2, 4ado corresponds to the 1st to 4th harmonics octave-reduced. The notes of 4ado create a harmonic seventh chord.

Intervals

# Cents Ratio Decimal Interval name Audio
0 0 1/1 1.000 perfect unison
1 386.3 5/4 1.250 just major third
2 702.0 3/2 1.500 just perfect fifth
3 968.8 7/4 1.750 harmonic seventh
4 1200.0 2/1 2.000 perfect octave