21/1

Interval information

Ratio	21/1
Factorization	3 × 7
Monzo	[0 1 0 1⟩
Size in cents	5270.781¢
Name	21st harmonic
Color name	c4z4, quadcozo 4th
FJS name	[math]\displaystyle{ \text{P32}^{7} }[/math]
Special properties	harmonic
Tenney norm (log2 nd)	4.39232
Weil norm (log2 max(n, d))	8.78463
Wilson norm (sopfr(nd))	10
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21/1, the 21st harmonic, is the harmonic past 20/1 and before 22/1. It is about four octaves and five semitone in size. Used in harmony, it sounds particularly wide: if the lower note is C2, the higher note will be about F6. Think of a soprano and a bass at their extremes. However, it can be approached as a stack of 3/1 and 7/1, making chords like 1-3-21, 1-7-21, or 1-3-7-21.

See also

• Gallery of just intervals