Along with his First Symphony, composed the following year, Perpetuum mobile (1963) serves as an example of Arvo Pärt's early serialist style, and bears virtually no resemblance (aurally, anyway) to the lush, introspective, tonally-centered "tintinnabular" style which he would develop in the 1970s—and with which he would come to be most closely identified.

Perpetuum mobile (perpetual motion) concerns itself with a simple curve, a crescendo that occurs in every musical dimension: dynamic, rhythmic, harmonic, and orchestrational. This curve is built according to rigid serial processes. It is based on a twelve-tone row—the same row, in fact, that (in inversion and transposition) would serve as the basis of the First Symphony. Each of the work's six overlapping sections is based on the either the regular row of twelve chromatic pitches, its inversion, its retrograde (the row backwards), or its retrograde-inversion (upside down and backwards). In each of the first four sections, the first tone of the row is given in a long note value—dotted whole notes in sections one and two, whole notes in three and four. These long tones are repeated a serially-derived number of times; as subsequent pitches in the tone row are introduced in different voices, they are layered on top of the long tones in increasingly smaller note values. Pärt goes beyond simple divisions of twos and threes, so that as more voices, pitches, and durations are added, a complicated layering of patterns develops that pits fours against fives against sixes, etc.

As the fourth section ends, this system is altered. The next tone row begins with rapid sextuplet sixteenth notes, then normal sixteenth notes, and so on down to the twelfth tone in the row, which appears as whole notes. Over the course of this section, the orchestration becomes even fuller, until an earsplitting tutti texture and a fff cymbal crash marks the peak of the curve. This overpowering wall of sound is then dismantled brick by brick, as the serial processes that constructed it likewise remove voices and diminish dynamics. The work ends even more ethereally than it began: whereas a lone violin had set the process in motion, the last sound we hear is the faint roar of a rolled cymbal.

Though its sonority is a far cry from that of the tintinnabular works, we see something in the process of Perpetuum mobile that hints at the careful construction of the "tintinnabula" technique: the establishment of and strict adherence to a musical process, which governs the overall textural and harmonic landscape of the work.



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