Metronome
A mechanical wind-up metronomemotion
The metronome was invented by Johann Nepomuk Mälzel.
Musicians use metronomes whenpracticeorderkeepstandard tempo; ie, keepsteady beat throughoutmusic. Evenpieces that do not require strict time (see rubato),metronomeusedgive an indication ofgeneral tempo intended bycomposer. Many pieces givetempo indication attop ofmanuscript.
One common typemetronome iswind-up metronome, which usesweight onend ofrodcontroltempo. The rod swings backforthtempo; mechanics insidemetronome produceclicking sound on each swing ofrod.
Most newer metronomeselectronic. The simplest electronic metronomes havedial or buttonscontroltempo; some can also producetuning note (usually A, 440 hertz). The button forms range from simple credit-card sized devices tocomplicated "Dr. Beat", manufactured by Boss. In addition tosimple pulse, this metronome can play polyrhythmscan "count aloud", usingsampled voice.
