The metronome is an instrument used to measure time and indicate the beat of musical compositions. The metronome produces a regular metric mark (beats, clicks), which can be set in beats per minute. These beats represent a marked aural pulse; some metronomes also include a visual synchronized movement, for example a pendulum swinging.
The origins of the metronome date back to the beginning of the 19th century, when it was patented by Johann Maelzel in 1815 as a tool for musicians , entitled "Instrument or Machine for the Improvement of Musical Performance, called Metronome" . This instrument is used by musicians to help maintain a constant time while playing, as well as to correct time problems for the musician, or to help internalize the sense of time and rhythm in music learners. After being patented in 1815, it is believed that the first notable composer to use the metronome in his music was none other than Ludwig Van Beethoven himself.
Because not all people have the same notion of rhythm and time, some experts suggest that the use of the metronome goes against the essence of music, since it has been shown that the Metronome Beat is very different from the Musical Beat, so in a piece of music with different emotional elements, in which many rhythms can be given, the use of the metronome is not appropriate. Musical time is almost always measured in beats per minute (BPM); therefore the metronomes can be adjusted to different times, which usually vary from 40 to 208 BPM; Another denotation for the time of the metronome is MM (or MM), Mälzel's Metronome.
This denotation is usually followed by a numerical value indicating the time, for example "MM = 60". There are currently three types of metronomes: mechanical, electrical, and software. Due to its infallible precision in keeping a certain time, the metronome has also been used as a musical instrument; such is the case of György Ligeti's 1962 composition “Poème Symphonique for 100 Metronomes” . Similarly, Maurice Ravel used three metronomes at different speeds for the intro of his opera “L'heure Espagnole” .
