(It.: ‘time’; Fr. mouvement; Ger. Zeitmass).
Literally, the ‘time’ of a musical composition, but more commonly used to describe musical speed or pacing. Tempo may be indicated in a variety of ways. Most familiar are metronomic designations that link a particular durational unit (usually the beat unit of the notated metre) with a particular duration in clock time (e.g. crotchet = 80 beats/minute). Also familiar are conventionalized descriptions of speed and gestural character – andante, allegro, langsam etc; (see Tempo and expression marks). There are also looser associations between metric notations and tempo, a vestige of earlier mensural practice, where, for example, 3/2 is sign of relatively slow tempo, 3/4 of moderate tempo and 3/8 of relatively quick tempo. Similarly, we retain a sense of the distinction between the half-circle (common time) and the crossed half-circle (alla breve), with the latter theoretically twice as fast (see Alla breve, Notation, §III, 3–6, and Proportional notation).
While tempo necessarily involves a determination of the appropriate durations for the various rhythmic units given in score, there is more to tempo than simply indexing crotchets and quavers to some amount of clock time. Epstein observed that ‘tempo is a consequence of the sum of all factors within a piece – the overall sense of a work’s themes, rhythms, articulations, “breathing”, motion, harmonic progressions, tonal movement, contrapuntal activity. … Tempo … is a reduction of this complex Gestalt into the element of speed per se, a speed that allows the overall, integrated bundle of musical elements to flow with a rightful sense’ (Shaping Time: Music, the Brain, and Performance, New York, 1995, p.99). A true sense of tempo, then, is a product of more than the successive note-to-note articulations; it involves the perception of motion within rhythmic groups and across entire phrases. Finding the ‘right’ tempo within and between sections of a piece is one of the subtlest and most difficult tasks facing the performer.
Changes in surface durations do not necessarily give rise to a change of tempo, as the augmentation or diminution of durational values may have little effect on the rate of the perceived pulse. Bona fide tempo changes may of course occur, either abruptly or gradually (via accelerando or ritardando) over the course of a composition, often rather dramatically. But it is worth noting that even within passages that seem to be in stable tempo, the beat rate is not mechanically constant, save in performances that involve electronic or mechanical means of articulating beats and rhythms. Rather, in normal performances tempo systematically fluctuates within the bar and the phrase.
Tempo is intertwined with our sense of pulse and metre, for without a regular series of pulses it is difficult to imagine any sense of tempo whatsoever. In a metric context, our sense of tempo is what allows us to distinguish subdivisions from beats and beats from downbeats (see Rhythm, §1, 4). The entire metric hierarchy, from the shortest subdivisions to the broadest levels of hypermetre, plays a pivotal role in establishing the ‘complex Gestalt’ of tempo.
See also Notation and Tempo and expression marks; for bibliography, see Rhythm.
JUSTIN LONDON