(Fr. battue; Ger. Takt, taktschlag; It. battuta).
Used synonymously with Beat to refer to regularly recurring articulations in the flow of musical time. Tactus is often used interchangeably with either ‘beat’ or ‘pulse’, but historically ‘tactus’ has a somewhat different meaning (see Rhythm, §II, 5). Pulses need not be phenomenally present in music, though they typically are. Rather, the sense of pulse arises through the listener’s cognitive and kinaesthetic response to the rhythmic organization of the musical surface (see Rhythm, §I, 4). Pulses usually are evenly spaced, though they need not be; for example, the ‘limping’ rhythms of Slavic folk music obtain that quality precisely in their arrangement of non-isochronous pulses. A clear sense of pulse is a necessary condition for musical metre, as it forms the temporal anchor for higher levels of metric structure (measures or bars marked by downbeats) as well as smaller levels of metric subdivision. Beats or pulses must fall within a certain temporal range, close to what historical discussions of tactus have defined relative to the average heartbeat rate of a resting adult. Very rapid or extremely slow articulations do not give rise to a sense of pulse – a reflection of the limitations of our psychological capabilities. The pulse of musical passage is a crucial, though not the only, aspect of our sense of tempo. Rapid tempo is correlated with a rapid pulse rate, and slow tempo with a slow pulse rate.
See also Metre and Tempo; for bibliography see Rhythm.
JUSTIN LONDON