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Use in chords Due to its high level of consonance, the perfect fifth contributes very little to the overall harmonic effect of any chords containing it (except power chords). In any situation that necessitates the omission of notes from a chord, such as for practical reasons of fingering, for example, the note forming the perfect fifth above the chord's root can often be safely omitted, its absence being barely, if at all, noticeable. A bare fifth, open fifth or empty fifth is a chord containing only a perfect fifth with no third. The closing chord of Mozart's Requiem is an example of a piece ending on an empty fifth, though these "chords" are common in Christian Sacred Harp singing and throughout rock music, especially hard rock, metal, and punk music, where overdriven or distorted guitar can make thirds sound muddy, and fast chord-based passages are made easier to play by combining the four most common guitar hand shapes into one. Rock musicians refer to them as power chords and often include octave doubling (i.e. their bass note is doubled one octave higher, e.g. F3-C4-F4). Use in tuning and tonal systems A perfect fifth in just intonation, a just fifth, corresponds to a pitch ratio of 3:2, while in 12-tone equal temperament, a perfect fifth is equal to seven semitones, a ratio of 1:27/12 (approximately 1.4983), or 700 cents, about two cents smaller. The just perfect fifth, together with the octave, forms the basis of Pythagorean tuning. A flattened perfect fifth is likewise the basis for meantone tuning. The circle of fifths is a model of pitch space for the chromatic scale (chromatic circle) which considers nearness not as adjacency but as the number of perfect fifths required to get from one note to another. The strings on violins, violas, and cellos are all tuned to perfect fifths unless in scordatura. See also | |||||||||||||||||||||||||||||
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