128/99

In 11-limit just intonation, 128/99 is an undecimal subfourth measuring about 444.8¢. It is the inversion of 99/64, the undecimal superfifth. This interval is also known as the minor fourth, and can additionally be somewhat similarly dubbed the Alpharabian paraminor fourth or even the just paraminor fourth. It is distinguished from the simpler 22/17 by the twosquare comma.

Interval information

Ratio	128/99
Factorization	27 × 3-2 × 11-1
Monzo	[7 -2 0 0 -1⟩
Size in cents	444.7721¢
Names	undecimal subfourth, minor fourth, Alpharabian paraminor fourth, just paraminor fourth
FJS name	[math]\displaystyle{ \text{P4}_{11} }[/math]
Special properties	reduced, reduced subharmonic
Tenney norm (log2 nd)	13.6294
Weil norm (log2 max(n, d))	14
Wilson norm (sopfr(nd))	31
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This interval is especially close to the 10th step of 27edo.

See also

• 99/64 – its octave complement
• 297/256 – its fifth complement
• Gallery of just intervals