Pulse (music)

Template:Short description {{#invoke:other uses|otheruses}}

In music theory, the pulse is a series of uniformly spaced beats—either audible or implied—that sets the tempo and is the scaffolding for the rhythm. By contrast, rhythm is always audible and can depart from the pulse. So while the rhythm may become too difficult for an untrained listener to fully match, nearly any listener instinctively matches the pulse by simply tapping uniformly, despite rhythmic variations in timing of sounds alongside the pulse.<ref>Fitch, W. Tecumseh and Rosenfeld, Andrew J. (2007).</ref>

Definitions

Metric levels: beat level shown in middle with division levels above and multiple levels below.

Simple quadruple drum pattern, rock drum kit. Despite the presence of eighth notes, there is a quarter note beat. Template:Audio

The tempo is the speed of the pulse. If a pulse becomes too fast it would become a drone; one that is too slow would be perceived as unconnected sounds.<ref name="perception">P. Fraisse, Les Structures Rhythmiques, Erasme Paris 1956, H Woodrow Time Perception in "A Handbook of Experimental Psychology", ed. S.S. Stevens, Wiley, NY 1951, both quoted at http://www.zeuxilogy.home.ro/media/manifesto.pdf Template:Webarchive (zeuxilogy.home.ro Template:Webarchive)</ref> When the period of any continuous beat is faster than 8–10 per second or slower than 1 per 1.5–2 seconds, it cannot be perceived as such.<ref name="perception" /> "Musical" pulses are generally specified in the range 40–240 beats per minute. The pulse is not necessarily the fastest or the slowest component of the rhythm but the one that is perceived as basic. This is currently most often designated as a crotchet (quarter note) when written (see time signature).

Pulse is related to and distinguished from rhythm (grouping), beats, and meter:

Pulse groups

Clear quarter note pulse in Template:Music at a tempo of Template:Music=120 Template:Audio. At Template:Music=600 the pulse becomes a drone Template:Audio, while at Template:Music=30 the pulse becomes disconnected sounds Template:Audio.

While ideal pulses are identical, when pulses are variously accented, this produces two- or three-pulse pulse groups such as strong–weak and strong–weak–weak<ref name="Winiold">Winold, Allen (1975). "Rhythm in Twentieth-Century Music", Aspects of Twentieth-Century Music. Wittlich, Gary (ed.). Englewood Cliffs, New Jersey: Prentice-Hall. Template:ISBN.</ref> and any longer group may be broken into such groups of two and three. In fact there is a natural tendency to perceptually group or differentiate an ideal pulse in this way. A repetitive, regularly accented pulse-group is called a metre.

Varied pulse groups equals non-isochronal multiple level Template:Audio.

Pulses can occur at multiple metric levels – see figure. Pulse groups may be distinguished as synchronous, if all pulses on slower levels coincide with those on faster levels, and nonsynchronous, if not.

An isochronal or equally spaced pulse on one level that uses varied pulse groups (rather than just one pulse group the whole piece) create a pulse on the (slower) multiple level that is non-isochronal (a stream of 2+3... at eighth-note level would create a pulse of a quarter note+dotted quarter note as its multiple level).

See also

• Composite rhythm
• Metre (hymn)
• Metre (poetry)
• Triple metre
• Duple and quadruple metre
• Sextuple metre
• Counting (music)