Metronome
A metronome (from Greek μέτρον (métron) 'measure', and νομός (nomós) 'law') is a device that produces an audible click or other sound at a uniform interval that can be set by the user, typically in beats per minute (BPM). Metronomes may also include synchronized visual motion, such as a swinging pendulum or a blinking light. Musicians—and others including dancers, athletes, and health professionals—often practise with a metronome to improve their timing, especially the ability to maintain a steady tempo with a regular beat or pulse. Composers and conductors often use numerical metronome markings to communicate their preferred tempos to musicians preparing for a performance.
For other uses, see Metronome (disambiguation).
A type of metronome was among the inventions of Andalusian polymath Abbas ibn Firnas (810–887). In 1815, German inventor Johann Maelzel patented a mechanical, wind-up metronome as a tool for musicians, under the title "Instrument/Machine for the Improvement of all Musical Performance, called Metronome".[1] In the 20th century, electronic metronomes and software metronomes were invented.
When interpreting emotion and other qualities in music, performers seldom play exactly on every beat. In a musically expressive performance, the pulse generally does not align with the clicks of a metronome.[2][3] This has led some musicians to criticize use of a metronome, because "musical time is replaced by clock time".[4]
Usage[edit]
Tempo indication[edit]
In written musical scores since the early 1800s, composers and conductors (or editors) often indicate their preferred tempos using BPM metronome speeds, with or without descriptive tempo markings, to help musicians prepare for a performance. Even works that do not require a strictly constant tempo, such as musical passages with rubato, sometimes provide BPM markings to indicate the general tempo. Another mark that denotes tempo is M.M. (or MM), for Maelzel's Metronome. The notation M.M. is usually followed by a note value and a number that indicates the tempo, as in M.M. 
= 60.
Ludwig van Beethoven, a personal acquaintance of Maelzel, became the first notable composer to indicate specific metronome markings in his music. This was done in December 1815, with the corrected copy of the score of the Cantata op. 112 containing Beethoven's first metronome mark.[19]
Pacing tool[edit]
Musicians often practise with metronomes to develop and maintain a sense of timing and tempo. Metronomes are also used as a training tool to achieve a desired performance speed—not only by musicians, but also by dancers,[20] runners,[21] swimmers,[22] and others.
Specific uses include learning to maintain tempos and beats consistently. For example, a musician fighting a tendency to speed up might practise a phrase repeatedly while slightly slowing the BPM setting each time, to play more steadily. A musician or athlete seeking to improve technical proficiency might set the metronome to gradually higher speeds until the desired tempo is achieved. This also helps to expose unintentional slowdowns due to technical challenges or fatigue. Additionally, recording musicians use click tracks from metronomes to help audio engineers synchronize audio tracks.
In health care, metronomes can be used to maintain the desired pacing in various physiological tests and procedures.[23] For example, CPR chest compressions are significantly more likely to follow the recommended 100–120 BPM when a hospital emergency room uses an audible metronome, or when rescuers in non-hospital settings can remember a suitably paced song as a "mental metronome".[24]
Reception[edit]
Positive views[edit]
The metronome is usually viewed positively by performers, teachers, conservatories, and musicologists (who spend considerable time analysing metronome markings). It is considered an excellent practice tool because of its steady beat, being "mathematically perfect and categorically correct".[38] This removes guesswork and aids musicians in various ways, including keeping tempos, countering tendencies to slow down or speed up unintentionally, monitoring technical progress, and increasing evenness and accuracy, especially in rapid passages. Metronomes are thus commonly used at all skill levels, from beginners to professional musicians, and are often recommended to music students without reservation.[39] As commentator/violist Miles Hoffman wrote in 1997: "Most music teachers consider the metronome indispensable, and most professional musicians, in fact, continue to practice with a metronome throughout their careers."[40] Some musicians took this view almost as soon as the metronome was invented in the early 19th century.[41][42] The online book Metronome Techniques includes a "Potpourri" chapter with dozens of quotations from music teachers in favour of metronome practice.[43]
Stricter rhythm in modern performance practice[edit]
The metronome has become very important in performance practice, and "largely unchallenged in musical pedagogy or scholarship since the 20th century".[44] In the 19th century, the metronome was usually not used for ticking all through a piece, but only to check the tempo and then set it aside. This is in contrast with many musicians today, who practise with the metronome in the background for the entirety of a piece of music, generally leading to steadier performances.[45]
Oboist/musicologist Bruce Haynes described the role of the metronome in modern performance style in detail in his book The End of Early Music. He emphasized that modern style is much more rhythmically rigid, compared with the effusive rubato and bluster characteristic of expressive 19th-century Romantic music. Because of this, musicologist and critic Richard Taruskin called Modernism "refuge in order and precision, hostility to subjectivity, to the vagaries of personality".[46] These qualities gave rise to the term metronomic, which music critics use to describe performances with an unyielding tempo, a mechanical rhythmic approach, and equal stress to all subintervals; violinist Sol Babitz considered it "sewing machine" style with limited flexibility.[46] Some writers have drawn parallels with a modern technological society that is ordered by the clock.[3][47]
Criticisms[edit]
Unlike approximate and descriptive tempo markings, a published metronome speed indicates a highly specific tempo that cannot adapt to variations in musical aesthetics, concert hall acoustics, or the instruments themselves.[48] This is one reason why composers including Felix Mendelssohn and Richard Wagner have criticized the publication of metronome marks.[49] As Johannes Brahms once commented regarding his German Requiem: "I think here as well as with all other music, the metronome is of no value. As far at least as my experience goes, everybody has, sooner or later, withdrawn his metronome marks."[50]
A metronome only provides a fixed, continuous beat. Therefore, metronome markings on sheet music provide a reference, but cannot accurately communicate the pulse, swing, or groove of music. The pulse is often irregular, e.g., in accelerando, rallentando, or expressive musical phrasing such as rubato.[51] Even such highly rhythmical musical forms as samba, if performed in a culturally authentic style consistent with recordings by early practitioners, cannot be captured with the beats of a metronome. Performances that are unfailingly regular rhythmically might be criticized as being metronomic, lacking the characteristic swing of the genre.[52]
Some have argued that "the metronome has no real musical value", hurting rather than helping musicians' sense of rhythm. The use of a metronome has been compared to the difference between mechanically-aided and freehand drawing, in that the output with a metronome is said to be rigid and hampering creativity.[53] American composer and critic Daniel Gregory Mason wrote that the use of the metronome is "dangerous" because it leads musicians to play by the measure or beat instead of the phrase, at the expense of liveliness, instinct, and rhythmical energy, "a dead body in place of the living musical organism".[54] Even proponents of the metronome have warned that its strict speed and repetition can hinder internal rhythm and musicality when "over-used".[55]
