33/28

In 11-limit just intonation, 33/28 is an undecimal minor third, specifically the pentacircle minor third, measuring about 284.4 cents. It is the fifth inverse of the pentacircle major third 14/11.

Interval information

Ratio	33/28
Factorization	2-2 × 3 × 7-1 × 11
Monzo	[-2 1 0 -1 1⟩
Size in cents	284.447¢
Names	undecimal minor third, pentacircle minor third
Color name	loru 2nd, 1or2
FJS name	[math]\displaystyle{ \text{M2}^{11}_{7} }[/math]
Special properties	reduced
Tenney norm (log2 nd)	9.85175
Weil norm (log2 max(n, d))	10.0888
Wilson norm (sopfr(nd))	25
Open this interval in xen-calc

In many notation systems based on the diatonic chain-of-fifths notation with commatic alterations (e.g. FJS, HEJI), it is a major second, as it is a Pythagorean major second plus an instance of 22/21, which is a stack consisting of an undecimal quartertone (33/32) and a septimal comma (64/63), neither of which changes the scale degree or quality.

However, it is only flat of the Pythagorean minor third of 32/27 (about 294.1 ¢) by a pentacircle comma (896/891), which makes it function sometimes as a minor third, hence the names.