Interval of equivalence: Difference between revisions
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If a [[periodic scale]] has an equave, the equave is typically the same as the [[period]] or a multiple thereof. | If a [[periodic scale]] has an equave, the equave is typically the same as the [[period]] or a multiple thereof. | ||
== Octave equivalence == | |||
The octave is usually called the '''interval of equivalence''', because tones separated by this interval are perceived as having the same [[pitch class]] despite their different absolute pitches. This equivalence is so strong that in most musical notation systems, notes separated by octaves share the same name. For the same reason, most [[scale]]s repeat at the octave. | |||
The perception of octave equivalence appears to have both biological and cultural components. | |||
Studies have shown that various non-human animals, including rhesus monkeys and rats, experience octave equivalence to a certain extent.<ref>Hoeschele M. [https://doi.org/10.3819/CCBR.2017.120002 ''Animal Pitch Perception: Melodies and Harmonies'']. Comp Cogn Behav Rev. 2017</ref> | |||
However, the degree of octave equivalence perception varies across cultures, particularly in those with non-Western musical traditions.<ref>Jacoby, Nori et al. [https://doi.org/10.1016/j.cub.2019.08.020 ''Universal and Non-universal Features of Musical Pitch Perception Revealed by Singing'']. Current Biology, 2019.</ref> | |||
When a different interval (such as the [[tritave]]) is used as the interval of equivalence, it is referred to as an [[equave]] or "formal octave". | |||
== Etymology == | == Etymology == | ||
Revision as of 17:50, 30 April 2025
The equave (/ˈiːkwɪv/ EE-kwiv or /ˈiːkwəv/ EE-kwəv), also called interval of equivalence, equivalence interval, formal octave[1][note 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.
Octave equivalence
The octave is usually called the interval of equivalence, because tones separated by this interval are perceived as having the same pitch class despite their different absolute pitches. This equivalence is so strong that in most musical notation systems, notes separated by octaves share the same name. For the same reason, most scales repeat at the octave.
The perception of octave equivalence appears to have both biological and cultural components. Studies have shown that various non-human animals, including rhesus monkeys and rats, experience octave equivalence to a certain extent.[3] However, the degree of octave equivalence perception varies across cultures, particularly in those with non-Western musical traditions.[4]
When a different interval (such as the tritave) is used as the interval of equivalence, it is referred to as an equave or "formal octave".
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
- ↑ 1.0 1.1 The terms formal octave and pseudo-octave are often used specifically to designate a stretched or compressed octave, but they may more generally designate any kind of equave.
References
- ↑ Op de Coul, E.F. Scala help.
- ↑ ASCL Specification. Ableton.
- ↑ Hoeschele M. Animal Pitch Perception: Melodies and Harmonies. Comp Cogn Behav Rev. 2017
- ↑ Jacoby, Nori et al. Universal and Non-universal Features of Musical Pitch Perception Revealed by Singing. Current Biology, 2019.