Fifth width
The fifth width (QB) indicates how far apart the individual tones of tone groups in the circle of fifths are. It provides information about the hearing perception of sounds. It also serves to clarify the tonal relationship between tone groups and keys.
Each tone of a tempered and diatonic tone supply is assigned to its position in the circle of fifths. If you now count the steps from fifth to fifth between the lowest and the highest position, you get the size of the fifth width. This principle can be applied to scales, chords, intervals, etc.
Examples
The scale of C major can also be written as a fifth layer: FCGDAEH. The width of the fifth is therefore 6 QB.
The notes of the chord CEG are in the circle of fifths at points C - G -DA- E . Here the fifth width is 4 QB.
The interval of the major sixth (e.g. CA) has a fifth width of 3 QB ( C -GD- A ), a minor sixth (e.g. C-As) has a fifth width of 4 QB ( As -Es-BF - C )
Effects on hearing
The fifth width has an impact on the sound. If the tones in the circle of fifths are close together (low QB), the result appears flat, if the tones are further apart (large QB), the sound is bulky. For example, a diminished triad (6 QB) is perceived as more pleasant than an excessive triad (8 QB).
literature
- Andreas Pilsenbeck: Jazz Theory I - Harmonics and Scales . Bärenreiter-Verlag, Kassel 2007, ISBN 978-3-7618-1966-1 , p. 14-15 .
- Zsolt Gárdonyi, Hubert Nordhoff: Harmonics . Möseler Verlag, Wolfenbüttel 1990, ISBN 978-3-7877-3035-3 , p. 189 f .