18/11

Interval information

Ratio	18/11
Factorization	2 × 32 × 11-1
Monzo	[1 2 0 0 -1⟩
Size in cents	852.5921¢
Names	undecimal neutral sixth, Alpharabian tendoneutral sixth
Color name	1u6, lu 6th
FJS name	[math]\displaystyle{ \text{M6}_{11} }[/math]
Special properties	reduced
Tenney norm (log2 nd)	7.62936
Weil norm (log2 max(n, d))	8.33985
Wilson norm (sopfr(nd))	19
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18/11 is an undecimal neutral sixth, and the octave complement of 11/9, the difference between the 11th and 9th harmonics. As this is the larger of two 11-limit neutral sixths obtained by modifying Pythagorean intervals by 33/32, it is dubbed the Alpharabian tendoneutral sixth in Alpharabian tuning.

Approximation

Edo approximations for 18/11 (852.59 ¢)
≤ 80edo, relative error ≤ 10%

Edo	Step size	Cents (¢)	Absolute error (¢)	Relative error (%)
7	5\7	857.14	+4.55	+2.65
14	10\14	857.14	+4.55	+5.31
17	12\17	847.06	-5.53	-7.84
21	15\21	857.14	+4.55	+7.96
24	17\24	850.00	-2.59	-5.18
31	22\31	851.61	-0.98	-2.53
38	27\38	852.63	+0.04	+0.13
45	32\45	853.33	+0.74	+2.78
52	37\52	853.85	+1.25	+5.43
55	39\55	850.91	-1.68	-7.71
59	42\59	854.24	+1.65	+8.09
62	44\62	851.61	-0.98	-5.06
69	49\69	852.17	-0.42	-2.40
76	54\76	852.63	+0.04	+0.25

See also

• 11/9 – its octave complement
• Gallery of just intervals
• Iceface tuning