Interval of equivalence

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The equave (/ˈiːkwɪv/ EE-kwiv or /ˈiːkwəv/ EE-kwəv), also called interval of equivalence, equivalence interval, formal octave[1] or pseudo-octave[2][note 1], is the interval such that pitches separated by it are considered psychoacoustically or formally equivalent and are elements of the same pitch class.

If a periodic scale has an equave, the equave is typically the same as the period or a multiple thereof.

Etymology

The term equave was coined by Inthar. It is a portmanteau of equivalence and octave.

Examples

  • In octave-repeating scales, the equave is typically 2/1.
  • In Bohlen–Pierce, the equave may be taken as 3/1.
  • In edfs, the equave may be taken as 3/2 or less commonly 9/4.

See also

Notes

  1. The term pseudo-octave generally designates any kind of equave, although it is sometimes used specifically to designate a stretched or compressed octave.

References

  1. Op de Coul, E.F. Scala help.
  2. ASCL Specification. Ableton.