Villa de Medici, Rome

Debussy revolutionized music, by rebelling against the rules of formal harmony (progression, structure and relationship of chords) and developed a style of composing only what pleased his ears, which he called "the rule of hearing" (Halford 10). Like Domenico Scarlatti, another famous composer, Debussy felt that if the music did not offend hearing, then it was okay to break the rules. Hence, he gave himself the freedom to experiment with different scales and arrangements of instruments to produce effects in harmony that had never been heard before.

Debussy frequently mixed together whole, half, and whole plus half steps, resulting in original scale harmonies that were neither major nor minor and he implemented rarely used techniques into his scores. A whole tone scale (a special type of scale) consists of seven whole steps (two notes whose keys are separated by a mutually adjacent key i.e. from C to D) and the dissonant tritones (a group of three whole steps whose notes conflict with each other) are either melodic or harmonic intervals. This scale, prior 1892, had only been used as a technique, but never as the basis for a piece. The medieval and renaissance modes, now widely used, consist of a major scale played in the Ionian mode (a scale pattern from C to C on the white keys) and a minor scale played in the Aeolian mode (a scale pattern from A to A on the white keys). The other modes he used were arranged in different patterns consisting of five whole and two half steps (two notes that are on adjacent keys i.e. from C to C#) that began on any note. To add color, mood and free modulation (changing keys from one tonic to another) to his pieces, Debussy liked to use chords from different keys in succession, which he called "floating chords" (Halford 11). Debussy's harmonic compostions also inclueded extensive use of pedal points, usually a tonic (the key that is the center of a scale or melody) or dominant note that is held or repeated through harmony changes surrounding it.

At a Paris Exposition, Debussy attended Javanese gamelon orchestras, which fascinated him and influenced him to create Oriental-sounding chord progressions. To imitate the gong effects in his pieces, he uses the pentatonic scale, and grace notes for the percussion effects. These original scales are often the basis for many of Debussy's themes and motives. The themes and motives are fragmentary and tentative. Most of his pieces begin with a single continuous theme that evolves through interactions between motives or intervals that produce a multiplicity of images (Hahn).

The instrumentation (composition for an instrumental ensemble) and orchestration (score written for an orchestra) of Debussy's music is untraditional in that he uses different instruments in new ways, like beginning an orchestra with a flute solo (a flute was usually given small roles in orchestras) in Prelude a l'apres midi d'un faune, or a new combination of instruments. Debussy also emphasis the quieter instruments like solo woodwinds, muted brass, and soft percussion effects, and he spread out the orchestral colors. In La Mer (1905), Debussy's orchestration was remarkable because he experimented with several solo instruments playing simultaneously at a relatively similar pitch to create the impression of a completely new instrument. The contrast of climax and anti-climax among the three movements is marvelous. The third movement of Nocturnes called Sirenes is most noted for Debussy's use of a vocalizing female chorus with contralto and soprano lines that cross several times.

1874-Debussy at the Conservatory in Paris

Other defining characteristics of Debussy's works include form, texture, meter, and rhythm. The French composer often avoided sharp sectional contrast and the constant repetition found in the sonata form. His texture is homophonic (one voice has the melody) with incidental counterpoint (short highlights where two or more melodic lines are played again one another). The music is idiomatic, featuring unusual voicings, and the meter is nonpulsatile with a defined metrical feeling. (Hahn).

The boldness in harmony of Debussy's unorthodox pieces earned him a great amount of criticism but Debussy refused to make concessions to the public. Ironically, sometimes their reaction only inspired him to do better. One such incident occured when Debussy entered the Conservatory of music in 1873, at the age of twelve. His style heavily strained his relationship with his harmony teacher, Emil Durand, a man who loved routine and took no real interest in his students. While his teacher frequently marked up his papers with corrections, deletions, and remarks, Durand was once noted to have said:`everything is wrong-"tout cela n'est guere orthodox-but he is talented, there can be no doubt about that!' (Ketting 11). Perhaps it was this acknowledgement of Debussy's talent that took the animosity out of their relationship. Debussy would later dedicate a trio for violin, violoncello, and piano (in G major, 3 movements) to Durand.