Chapter 1.4. Periodicity We do not consider periodicity as either basic material nor as the unit of rhythmic structure, but the most simple, most probable phenomenon; it is tempting to see it as an ideal point of reference for the perception of time, as is a sinusoidal sound for the perception of pitches, but not at all the a priori foundation of a hierarchical system. …Periodicity is irreplaceable; it allows a pause in the music’s unfolding, the suspension of time and, sometimes, a redundancy helpful to our powers of comprehension. When the musical structure demands it, we use it for its intrinsic qualities, avoiding both rejection and obsession.51 The word periodicity, according to the Oxford English Dictionary, is defined as “the quality or character of being periodic; the quality of regular recurrence; tendency to recur especially at regular intervals.”52 Periodicity in music refers to an uninterrupted temporal phenomenon in which an event or a series of events of a fixed duration is repeated at a regular interval.53 Periodicity, then, can be understood as comprised of two essential elements: pulsation and event. Pulsation is the underlying pulse that occurs at the beginning of each cycle (or period), and it is an “uninterrupted sequence of reference points with respect to which rhythmic flow is organized.”54 Event is the object that is reiterated in each cycle.55 Example 1.4.1 demonstrates a pulsation, which in fact can be
51
Gérard Grisey, “Tempus ex Machina: A Composer’s Reflections on Musical Time,” Contemporary Music Review 2, (1987): 245-247. 52 Oxford English Dictionary, 2nd ed., s.v. “periodicity.” 53 "All forms of music in the Central Aferican Republic are constructed according to a principle of periodicity." Simha Arom, African Polyphony and Polyrhythm: Musical Structure and Methodology, translated by Martin Thom, Barbara Tuckett and Raymond Boyd (Cambridge: Cambridge University Press, 1991): 230. 54 Simha Arom, African Polyphony and Polyrhythm, 202. 55 "Metrically speaking, the period can thus be broken down on two lower levels, into the pulsation and the operational values it contains. We must remember tat, characteristically, this organisation involves no intermediate level between the period itself and the pulsation, consisting of a regular accentual system, i.e., the 'measure' with its characteristic strong beat, as found in Western music. Consequently, the 'beats' comprising the period all have equal status." Simha Arom, African Polyphony and Polyrhythm, 231.
39