121/64

121/64, the Alpharabian major seventh, or octave-reduced 121st harmonic, is an 11-limit interval that results from stacking two 11/8 fourths. While the FJS and other systems that treat 33/32 as a comma end up designating 121/64 as a "minor seventh", this interval actually functions as a kind of major seventh- a property that is particularly evident when you consider that its octave complement is a type of diatonic semitone.

See also

• 128/121 – its octave complement