18/1

Interval information

Ratio	18/1
Factorization	2 × 32
Monzo	[1 2⟩
Size in cents	5003.91¢
Name	18th harmonic
FJS name	[math]\displaystyle{ \text{M30} }[/math]
Special properties	harmonic
Tenney height (log2 nd)	4.16993
Weil height (log2 max(n, d))	8.33985
Wilson height (sopfr(nd))	8
Harmonic entropy (Shannon, [math]\displaystyle{ \sqrt{nd} }[/math])	~2.37457 bits
Open this interval in xen-calc

18/1, the 18th harmonic, is the harmonic past 17/1 and before 19/1. It is about four octaves and two semitones in size. Used in harmony, it sounds particularly wide: if the lower note is C2, the higher note will be about D6. Think of a soprano and a bass at their extremes. Like 12/1, it can be approached in various ways of stacking, such as 1–2–3–6–9–18, an alternate sequence of octaves and fifths.

See also

• 9/8 – its octave-reduced form