3.1.1 Debussy’s Voiles

What types of modes are there? Basically, quite a few, as long as the mode does not have to meet special structural requirements. For instance, we find the use of free modes in the work of Iannis Xenakis (see Chapter V, 10.5) As soon as modes have to meet strict structural requirements, the number becomes much more limited. In Messiaen’s work we find an obsessive use of modes that have one or more sequences built in and that limit themselves in size to the octave. That leaves only seven modes (see 3.1.2, p. 95).

All other modes within the octave are formed irregularly. The more well-known are: - pentatonic modes, literally a row of five tones, the best-known is the black-key row. - church modes (Dorian, Phrygian, Lydian and Mixolydian); with their structure of steps of a major/minor second. These modes are basically diatonic tone rows. When the usual diatonic tone rows are applied without cadential meaning they can also be regarded as modes (Aeolian and Ionic).

3.1.1 DEBUSSY’S VOILES The most radical use of modes in the work of Debussy occurs in Voiles (Préludes, book 1 nr. 2) from 1909 (see Ex. 9). The whole piece consists of one whole-tone region, (except for a few chromatic passing notes), an ostinato of one bass note and a number of contrasting bars that are written in the pentatonic tone row (in this case all the black keys of the piano). The chord material is mainly made up of augmented triads. No key can be determined in this work.

Some theorists point out that the constantly repeated note b-flat in the bass forms its natural root tone, but that is merely a repeated tone without any cadential function. When we hit only the C-note on the keyboard for a while, this does not equal the tonality of C. The argument that tone repetition automatically creates a key is a dogma from the world of dodecaphony. Ex. 8: Anti-German cartoon, 1914 (see colour page VIII). Ex. 9: Page 5 of Debussy, Voiles, see next page.

Ex. 9: Page 3 of Debussy, Voiles.