metronome for music practice
BPM stands for beats per minute, and it is the number that sets the speed of any piece of music: the higher the BPM, the shorter the gap between one beat and the next, and that relationship is the foundation of any rhythmic practice with a metronome.
60000 divided by 120 gives 500; it is one of the most common starting tempos for practice because it stays comfortable both for counting and for playing.
60000 divided by 76 gives about 789 ms; slow tempos like this one are used to train precision before speeding up.
60000 divided by 200 gives 300 ms; at that short interval, the drift from a plain `setInterval` would already be audible, which is why the audio clock matters.
BPM stands for beats per minute. It is the standard measure of musical tempo. 60 BPM = one beat per second. 120 BPM = two beats per second. Common tempos: Largo (40–60), Andante (76–108), Allegro (120–168), Presto (168–200).
Divide 60000 (the number of milliseconds in a minute) by the BPM. At 90 BPM, for example, the interval is 60000/90, roughly 667 ms between one beat and the next.
It happens when the implementation relies only on `setInterval` to trigger the sound, because that timer is not guaranteed by the browser to fire at the exact millisecond; the fix is to schedule the sound against the `AudioContext` clock, which does not suffer that kind of drift.
It is the first beat of each measure, played with a louder or different sound to mark where the beat group restarts; in 4/4, it is beat 1 of every group of 4.
Most popular music sits between 60 and 180 BPM; below that range you enter very slow ballad tempos (Largo, Grave), and above it fast electronic genres like drum and bass, which often run past 160 to 180 BPM.