Octave (interval region): Difference between revisions

{{Wikipedia|Octave}}

A '''perfect octave''' ('''P8''') or '''octave''' ('''8ve''') is an [[interval]] that is approximately 1200 [[cent]]s in [[interval size measure|size]]. While a rough tuning range for octaves is sharper than 1170 cents according to [[Margo Schulter]]'s theory of interval regions, the term ''octave'' tends to imply a function within music that only works with intervals that corresponding to a [[just]] [[ratio]] of [[2/1]] or a close approximation thereof, usually preferred to be sharp-tempered if tempered. Other intervals are also classified as octaves, sometimes called '''wolf octaves''' or '''imperfect octaves''', if they are reasonably mapped to seven steps of the diatonic scale and twelve steps of the chromatic scale, reflecting the period and equave of both. Enharmonic intervals may be found at multiples of 12 steps along the chain of fifths, such as the diminished ninth (mapped to 8\7) and augmented seventh (6\7).  

The aforementioned function is the interval of equivalence, or [[equave]], because tones separated by an octave are perceived to have the same or similar [[pitch class]] to the average human listener. The reason for this phenomenon is probably due to the strong concordance of the octave or the strong amplitude of the second [[harmonic]] in most harmonic instruments.  As such, it is common practice to [[octave-reduce]] intervals so that they lie within the octave.  

For the sake of simplicity, this page also covers '''interseptimal seventh-octaves''', which are approximately 1150 cents in size and are the complements of [[Comma and diesis|dieses]]. Thus, the interval region considered as "octave" for the purpose of this page is 1140-1200 cents.

 

{| class="wikitable sortable center-all right-3"

! class="unsortable" | Interval

! Distance <br>from 2/1

|}

== See also ==