MusicReasonResource
Tempo, Meter, Beat Units, and SubdivisionInteractive
A BPM number means nothing on its own; it only describes tempo once you state which note value counts as one beat.
MusicReasonResourceTempo, Meter, Beat Units, and Subdivision
A BPM number by itself does not describe a tempo. "120" could mean 120 quarter notes per minute or 120 dotted-quarter notes per minute, and those are genuinely different speeds. Meter adds a second layer on top of tempo: how beats are grouped, not just how long each one lasts.
BPM only means something with a stated beat unit
120 BPM in 4/4 is almost always counted as 120 quarter-note beats per minute, 500 ms each. 120 BPM in 6/8 is conventionally counted as 120 dotted-quarter beats per minute (two big beats per bar), even though the bar also contains six eighth notes. The numerator and denominator of a time signature describe grouping and note value, not the metronome's actual beat unit, which is why Time Signature Explorer states the conventional beat unit explicitly for each meter instead of assuming quarter notes everywhere.
A worked subdivision, at your own tempo
The dotted and triplet relationships never change: a dot always multiplies a duration by 3/2, and a triplet always multiplies it by 2/3, regardless of tempo. What changes with BPM is only the base quarter-note duration (60,000 / BPM in milliseconds) that every other value scales from. Subdivision Trainer and Tempo-Synced Delay Calculator both use this identical relationship for different purposes: one for rhythmic practice, one for tempo-locked studio timing.
Tap Tempo's limits are about your taps, not the math
Tap Tempo averages the intervals between your taps and discards statistical outliers, so a few uneven taps at the start pull the running estimate before it settles on a stable value. The tool reports the same averaging method every time; the variability you see reflects your own tap consistency, not a hidden device or browser quirk.
Why the Metronome does not use a plain JavaScript timer
A naive repeating timer can drift under browser load, since the browser only guarantees a timer fires no earlier than requested, never exactly on time. MusicReason's Metronome instead uses a look-ahead scheduler that queues each click slightly ahead of when it should sound, locked to the audio clock rather than to JavaScript's own timing, which is what keeps a long metronome session from slowly drifting off tempo.
Frequently asked questions
The beat duration is identical, 500 ms, but the felt pulse usually is not. 6/8 at 120 BPM is normally counted in two dotted-quarter beats per measure, not six eighth-note beats, so the practical feel is closer to a fast two than a moderate six.
Tap Tempo averages the intervals between your taps and discards outliers, so a few uneven taps at the start pull the estimate before it settles. It reports the same statistical average method every time, not a device-specific timing quirk.
A browser timer alone can drift under load. MusicReason's Metronome uses a look-ahead audio-clock scheduler instead of a plain timer, scheduling clicks slightly ahead of when they play so the beat stays locked to the audio clock rather than to JavaScript's own timing.