Perfect intervals

In music, an octave (: eighth) or perfect octave (sometimes called the diapason) is an interval between two notes, one having twice the frequency of vibration of the other. For instance, the interval between C4 and C5 (in scientific pitch notation) is an octave. { \override Score.TimeSignature 'stencil = ##f \relative c' { \time 4/4 \set Score.tempoHideNote = ##t \tempo 1 = 20 1 } }

In music, unison is two or more musical parts that sound either the same pitch or pitches separated by intervals of one or more octaves, usually at the same time. Rhythmic unison is another term for homorhythm.

musical interval spanning five staff positions and seven semitones, whose frequency ratio is approximately 3:2=1.5 (in equal temperament, ¹²√2⁷=1.498…)

musical interval spanning four staff positions and five semitones, with a frequency ratio of approximately 4:3=1.333… (in equal temperament, ¹²√2⁵ = 1.335…)

musical interval spanning fifteen staff positions and twenty-four semitones