Patrick De Clerck wants to start every composition with a clean slate, even though this is never fully possible. A simple and transparent ground plan forms the basis for his compositions. The compositional material of his work can be reduced to one single page of basic material, from which he develops several musical ideas. When he has elaborated one idea, he moves on to the next. This ground plan lends a certain orientation to the music, enabling him to avoid the simple juxtaposition of musical ideas. He uses neo-tonal speech in his work. As do many post-soviet composers, Patrick De Clerck develops the tension between consonant and dissonant on an emotional basis and not on the basis of a rational system. Nevertheless, his sound image is closer to the late-romantic tradition than to that of the post-soviet composers. De Clerck's ultimate goal is to one day write music within his own sound universe which carries a certain orientation, even in the absence of a melody, as a river would stream to the sea.
Composition and execution are two separate dimensions in his view. The composition is finished with the completion of the score. The written reflection of the score constitutes the point of departure for the execution. Rather than in the technical aspect of the compositions, the real difficulty resides in their interpretation. The music should try to evoke a reaction, which is possible only if the interpreter couples a solid musical background with an intense commitment to the work. This is why the composer always works so closely with the performers of his music. He explores the possibilities and steers the musicians in a certain direction. A performance of his work should never be limited to a literal recreation of the score; it should be an interpretation by musicians prepared to take their own responsibility.
Patrick De Clerck mainly writes for small ensembles, either vocal or purely instrumental. The choice of text is of particular importance in his vocal music. These compositions are based on texts by, amongst others, Michelangelo, Fiodor Sologub, Anna Akhmatova and Osip Mandelstam. In his vocal work he seeks to achieve a far-reaching fusion of text and music. In 1993, the Belgian National Opera commissioned the Northern Elegies. The composition is based on Akhmatova's First Northern Elegy. The text spans the four parts of the composition, allowing the composer to create a monologue to the accompaniment of the piano. Canto I (1995) and Canto II (1995) share the same text but differ in interpretation, thereby throwing a different light on the text. De Clerck sometimes introduces alienating aspects into his music. In Canto IV (1997), he at times teams up one instrumentalist and one vocalist. Both have the same melody, but only the vocalist has a text. This generates an unusual fusion of text and pure music. In his cycle of songs Mignon (1999), the composer creates alienation on a different level, that is to say that the vocalist starts out as a page-turner for the pianist.
Patrick De Clerck has also written longer vocal compositions such as his chamber opera Re (1988-1989) and the scenic cantata Angelo (1991-1992).
As regards formal structure, his instrumental works generally consist of five distinct parts. There is a well-balanced alternation of slow and fast sections, while the compositions as a whole lean toward the slow side. The various parts are linked by the underlying concept of the particular composition. His string quartet Sferen (Spheres, 1992) is constructed according to the Pythagorean proportions (1:2:3:4:5). The first part of the oeuvre is a cantus with variations that reveal the different tempi of the following parts. De Clerck often elaborates his musical material in a fragmentary way. In the prologue of his A Stringtrio (1990), the musical ideas of the next five parts are briefly introduced. One idea is developed in each part, but the basic idea of each part is juxtaposed to ideas from the other parts.
Apart from music for chamber ensembles, Patrick De Clerck also writes for solo instruments - e.g. Elegia for solo piano (1997), Ai Morti for violin - or for the orchestra - e.g. A Symphony (2000) or Pianoconcerto (2001-2002). The title "A Symphony" contains a word game. The 'a' can be interpreted in three different ways. When stressing 'symphony', the 'a' refers to the genre of the composition. Placing the emphasis on the 'a' refers to the fact that this composition is one of many within the genre. In addition, the work is constructed around the central tone 'A' (= La). The dynamic process occurs on the rhythmic level rather than on the melodic or harmonic level. At the conclusion of the work, several instruments are required to produce an air sound at the pitch of 'la'. Instead of providing a highly detailed description of the required technique, he uses a simple notation so as to force the musicians to create their own solution. This allows De Clerck to avoid all complexity in his notation.