40 BPM Metronome

40 Beats per Minute Metronome click with beats and 4/4 bars counting. Grave -- slow and solemn (20--40 BPM) Lento -- slowly (40--45 BPM) Largo -- broadly (45--50 BPM) A metronome is any device that produces regular, metrical ticks (beats, clicks) — settable in beats per minute. These ticks represent a fixed, regular aural pulse; some metronomes also include synchronized visual motion (e.g. pendulum-swing). The metronome dates from the early 19th century, where it was patented by Johann Maelzel in 1815 as a tool for musicians, under the title "Instrument/Machine for the Improvement of all Musical Performance, called Metronome"