Editing Perfect fifth (section)

[[File:Perfect fifth on C.png|thumb|Perfect fifth<br />[[File:Perfect fifth on C.mid|thumb|center|Equal tempered]][[File:Just perfect fifth on C.mid|thumb|center|Just]]]]
{{Infobox interval|
       main_interval_name = perfect fifth|
       inverse = [[perfect fourth]]|
       complement = [[perfect fourth]]|
       other_names = diapente|
       abbreviation = P5 |
       semitones = 7 |
       interval_class = 5 |
       just_interval = 3:2|
       cents_equal_temperament = 700|
       cents_24T_equal_temperament = |
       cents_just_intonation = 701.955{{refn|<math>1200 \times \log_2(1.5)</math>}}
}}

[[File:The perfect fifth.gif|thumb|The perfect fifth with two strings]]

{{Image frame|content=<score>  { <<
 \new Staff \with{ \magnifyStaff #4/3 } \relative c' { 
  \key c \major \clef treble \override Score.TimeSignature #'stencil = ##f \time 3/4
   <g' d'> <b fis'> <d, a'>
}
 \new Staff \with{ \magnifyStaff #4/3 } \relative c' { 
  \key c \major \clef bass \override Score.TimeSignature #'stencil = ##f \time 3/4
   <c, g'> <a e'> <f' c'>
} >> } 
</score>|width=|align=|caption=Examples of perfect fifth intervals}}

In [[music theory]], a '''perfect fifth''' is the [[Interval (music)|musical interval]] corresponding to a pair of [[pitch (music)|pitches]] with a frequency ratio of 3:2, or very nearly so.

In [[classical music]] from [[Western culture]], a fifth is the interval from the first to the last of the first five consecutive [[Musical note|note]]s in a [[diatonic scale]].<ref>[[Don Michael Randel]] (2003), "Interval", ''Harvard Dictionary of Music'', fourth edition (Cambridge, Massachusetts: Harvard University Press): p. 413.</ref> The perfect fifth (often abbreviated '''P5''') spans seven [[semitone]]s, while the [[Tritone|diminished fifth]] spans six and the [[augmented fifth]] spans eight semitones. For example, the interval from C to G is a perfect fifth, as the note G lies seven semitones above C.

The perfect fifth may be derived from the [[Harmonic series (music)|harmonic series]] as the interval between the second and third harmonics. In a diatonic scale, the [[dominant (music)|dominant]] note is a perfect fifth above the [[tonic (music)|tonic]] note.

The perfect fifth is more [[consonance and dissonance|consonant]], or stable, than any other interval except the [[unison]] and the [[octave]]. It occurs above the [[root (chord)|root]] of all [[Major chord|major]] and [[Minor chord|minor]] chords (triads) and their [[extended chords|extensions]]. Until the late 19th century, it was often referred to by one of its Greek names, ''diapente''.<ref>{{cite book|title=A Dictionary of Christian Antiquities|author1=William Smith|author1-link=William Smith (lexicographer)|author2=Samuel Cheetham|author2-link=Samuel Cheetham (priest)|location=London|publisher=John Murray|year=1875|page=550|isbn=9780790582290|url=https://books.google.com/books?id=1LIPFk6oFVkC&q=diatessaron+diapason+diapente+fourth+fifth&pg=PA550}}</ref> Its [[Inversion (interval)|inversion]] is the [[perfect fourth]]. The octave of the fifth is the twelfth.

A perfect fifth is at the start of "[[Twinkle, Twinkle, Little Star]]"; the pitch of the first "twinkle" is the root note and the pitch of the second "twinkle" is a perfect fifth above it.