*Augmented octave and diminished unison on C = C♯. Equal-tempered: 21/12:1 = 100 cents. MIDI pitch bend: none Note how the diminished unison is essentially equivalent to the augmented unison.
A thirteenth chord "collapsed" into one octave results in a dissonant, seemingly secundal[1] tone cluster. Created by Hyacinth (talk) 22:18, 5 July 2009 using Sibelius 5.