polirritmia

Polirritmia, or polyrhythm, is the simultaneous use of two or more rhythmic streams with different periodicities within the same temporal space. The term combines the Greek roots poly- (many) and rhythmós (beat or tempo). In practice, a musician or ensemble may perform rhythms that subdivide the beat in contrasting ways, creating a layered texture in which the accents and pulses do not always align.

Common forms of polyrhythm include ratios such as 3:2, 4:3, or more complex combinations where one layer plays three notes in the time another layer plays two. A 3:2 polyrhythm, for example, fits three evenly spaced notes into the duration of two evenly spaced notes, producing a crosswise alignment that gradually shifts relative to a steady pulse. Polyrhythms are distinct from hemiolas, where a metric shift occurs across larger spans, and from cross-rhythms, which emphasize contrasting meters or accents against a fixed tempo.

Cultural and historical contexts vary. West African musical traditions are frequently cited for their prominent use of layered rhythms and interlocking patterns. Polyrhythms also appear in Indian, Balkan, and Afro-Cuban music, as well as in contemporary classical and experimental genres. In jazz and modern classical music, composers and performers exploit polyrhythms to create rhythmic complexity and momentum, sometimes aligning the layers against a common pulse, other times treating the layers as independent accents.

Notation and performance practice typically indicate polyrhythms through tuplet markings or sequential patterns, with musicians coordinating by listening to or counting against a shared reference beat. Polirritmia remains a foundational technique for achieving rhythmic richness and ensemble interaction across many musical styles.