Polymodal chromaticism

Polymodal chromaticism is a musical term coined by composer, ethnomusicologist and pianist Béla Bartók. The technique became a means in Bartók's composition to avoid tonality in the sense used between approx. 1600-1900 and yet a different approach than Arnold Schoenberg and his followers in the Second Viennese School and later serialists took, not to be strained within the limits of tonality.

Bartók had realised that both melodic minor-scales gave rise to four chromatic steps between the scales' 5th and the rising melodic minor-scale's 7th degrees when superimposed. Consequently, he started investigating if the same pattern could be established in some way in the beginning of any scales and came to realise that superimposing a Phrygian and a Lydian scale with the same finale resulted in what looked like a chromatic scale. Bartók's twelve-tone Phrygian/Lydian polymode, however, differed from the chromatic scale as used by e.g. the late-Romantic composers, like Richard Strauss and Richard Wagner, since during the late 1800s the chromatic altering of a chord or melody was an altering of a chord in strict relation to its functional non-altered chord version. A melodic or chordal alteration through the twelve-tone Phrygian/Lydian polymode, the other hand, were "diatonic ingrediences in a diatonic modal scale." (Béla Bartók Essays)

    Phrygian mode (C):
    C  - Db - Eb - F  - G  - Ab - Bb

    Lydian mode (C):
    C  - D  - E  - F# - G  - A  - B

    Twelve-tone Phrygian/Lydian polymode (C):
    C  - Db - D  - Eb  - E - F  - F# - G - Ab - A - Bb - B

Hence, melodies could be developed and transformed through diatonic extention and chromatic compression to almost seem like new melodies, but still have coherent links to their original forms. Bartók described this as a new means to develop a melody, e.g. in addition to what during the 17th and 18th centuries had been known to all Western composers, namely augmentation and diminution.

As an outcome of this, Bartók started to superimpose all possible diatonic modes on each other and was thus able to extend and compress melodies in all ways that suited him, yet never being restricted by Baroque-Romantic tonality, yet never having to use a strict serial method such as the twelve-tone technique.

In Bartók's ethnomusicological studies he in 1941 came in contact with the music of Dalmatia and realised to his surprise that the Dalmatian folk-music used techniques that resembled polymodal chromaticism. Bartók had, however, defined and started using polymodal chromaticism in his own writing before this and the effect of his discovery became purely inspirational to continue development of the technique.