Bitonality is a term from music and describes the simultaneous use of two tones . It is the most common type of polytonality (polys = a lot), which conceptually also includes the simultaneous use of more than two keys.
A well-known example of bitonality is the fanfare at the beginning of Igor Stravinsky's ballet Petrushka . The two clarinets play an almost identical melody at the same time. Only the first plays in C major and the second in F sharp major:
Bitonality is often mentioned in connection with atonal music, but its use is based entirely on functional theory and thus on the harmonic relationship between keys and cadence . Only the completely free use of chords and the layering of several keys or many individual tones on top of each other (which leads to a cluster ) in the 20th century detached the term from its historical context. See also Upper Structure .
Bitonality emerged as part of the expansion of functional harmony in the late 19th century. Especially in works by Richard Strauss you can find harmonic connections that can hardly be explained from the functional harmony, but are nevertheless placed in a tonal context (example: the opera Salome ). They are composed mainly because of an emotional impact. These twists, which are still distantly referred to as mediants in a harmonic context (often questionable) , can also be found in works by Franz Schreker , Erich Wolfgang Korngold , Alexander von Zemlinsky and in the cantata composed in 1911 by Joseph Marx , "Herbstchor an Pan", and even in his early songs from 1905-08.
“Real” bitonal pieces can be found in the piano works of Claude Debussy , later Charles Koechlin and Charles Ives . A very good example are some pieces from Béla Bartók's “Mikrokosmos” , in which different accidentals are noted for the right and left hand. Earlier examples, such as Wolfgang Amadeus Mozart's A Musical Fun , probably use the technology because of a strange effect.
In the sound result, the two tones of the ear can be clearly distinguished in the bitonality. Depending on how far apart these are in the circle of fifths and contain common tones, a more tonal or atonal sensation arises when listening. The works by Ives and Koechlin finally turn away from the tonal context, Koechlin uses the juxtaposition of different keys to create warm, impressionistic colors, Ives, on the other hand, was fascinated by the acoustic effect of several brass bands playing on each other.
Since hard bop in jazz, melodies have often been led with a distance of pure fourths (also with Wagner). This means that, strictly speaking, they are played in two keys. On the other hand, they can be conducted in such a way that they never form an excessive fourth (tritone), e.g. B .:
- f - g - a - b - c - d - e - f
- c - d - e - f - g - a - h - c
so you are actually in no key and play atonal.
On the other hand, you can play more semitones and you are almost in a blues tone:
- f - g - a - b - h - c - d - e - f
- c - d - e - f -fis- g - a - h - c
- f - g - a - b - h - c - d - es- e - f
- c - d - e - f -fis- g - a - b - h - c
In jazz some of this is dealt with in the fourth harmonic .