Ametrical Music

Definition: Music organized by precise rhythmic values and patterns rather than by regular metric framework (measures with recurring accent patterns and equal durational units).

Messiaen's Treatment: Messiaen distinguishes between measured music (organized by bar-lines, regular beats, and metric hierarchy) and ametrical music (organized by exact durational values without recurring metric structures). He advocates replacing conventional metric thinking—concepts of measure and beat—with awareness of short durational values (such as the sixteenth-note) and their free multiplicative combinations. This shift necessitates precise rhythmic rules in place of metric conventions. Messiaen notes that bar-lines in his examples serve only to mark periods or delineate phrase endings and accidentals, not to establish metric accent patterns.

Modern Context: Contemporary music theory distinguishes between metric and ametric organization, recognizing that Western common-practice music privileges metric hierarchy (strong/weak beat organization within measures) while many non-Western traditions and twentieth-century Western composers explore ametric alternatives. Messiaen's position anticipates the development of additive rhythm theory, where durations are conceived as combinations of basic pulse units rather than divisions of metric spans. His approach parallels other modernist rejections of traditional meter (Stravinsky's irregular barring, Varèse's rhythmic blocks, Carter's metric modulation) while grounding this rejection in systematic rules derived from non-Western practice.

The terminology "ametrical" itself requires clarification: Messiaen does not mean rhythmically free or unmeasured (like unmeasured preludes or cadenzas) but rather precisely measured without metric regularity. Contemporary theorists might use terms like "non-isochronous," "additive rhythm," or "asymmetrical rhythm."

Examples: All examples in this chapter demonstrate ametric construction; Example 1 specifically illustrates Stravinsky's ametric procedure.