Period (music)

In music theory, the term period refers to forms of repetition and contrast between adjacent small-scale formal structures such as phrases.

"[3] Earlier and later usages vary somewhat, but usually refer to notions of symmetry, difference, and an open section followed by a closure.

In other cases, the consequent may differ greatly (for example, the period in the beginning of the second movement of the Pathetique Sonata).

Four-beat periods may be represented in Western notation as a single bar, as in the examples given here; but see "Clave" below for an alternate presentation.

In explaining the structure of music guided by the five-stroke African bell pattern known in Cuba as clave (Spanish for 'key' or 'code'), Grenet uses what could be considered a definition of period: "We find that all its melodic design is constructed on a rhythmic pattern of two bars, as though both were only one, the first is antecedent, strong, and the second is consequent, weak.

[31] Metric consonance is achieved when the last stroke of clave coincides with the last main beat (last quarter note) of the consequent bar.

As the pattern is repeated, an alternation from one polarity to the other takes place creating pulse and rhythmic drive.

Should the drums fall out of clave (and in contemporary practice they sometimes do) the internal momentum of the rhythm will be dissipated and perhaps even broken—Amira and Cornelius (1992).

[34]Note that in most Cuban and Cuban-based popular music, such as salsa, the two halves of the pattern are reversed: the two-side is the precedent, the three-side the consequent.

The concept and feel are so basic to the musical style that both musicians and listeners sense them even when not actually sounded.