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Metric Modulation Calculator
Music knowledge / Guides and practical tools
About this reference
From the music-learning collection, adapted for Philojain Music Muse. Referenced sources remain credited in the article.
Metric modulation moves the beat. A note value from the old tempo is re-heard as the beat of the new one, so the pulse relocates rather than merely speeding up or slowing down. Enter the tempo you are leaving and the two note values that pivot, and this works out the tempo you arrive at and the pulse the two sections share.
The calculator
You supply the tempo and the two note values. Nothing here suggests a tempo, a genre convention or a "correct" modulation — the arithmetic is the same whatever the music is.
What metric modulation actually is
The distinction is worth getting right because the two things sound different and are constantly confused. In a half-time or double-time feel, the pulse stays exactly where it was and the band changes what it plays across it — the drummer moves the backbeat, the riff doubles or halves, but a metronome running through the section never changes speed. In a metric modulation, a note value from the old tempo is adopted as the beat of the new one. The metronome does change, and it changes by a ratio the old music already contained, which is why the join sounds inevitable rather than abrupt.
A common example: at 120 BPM, the dotted quarter lasts as long as three eighth notes. Re-hear that dotted quarter as the new quarter and the tempo becomes 80 — the eighths never changed speed, but the beat now falls in a different place. The shared pulse is what carries the listener across; without one, a tempo change is just a tempo change.
How to enter the values
Both note values are entered as divisions of a whole note: 4 for a quarter, 8 for an eighth, 16 for a sixteenth, 2 for a half. Put 1 in the dotted field to add half the value again, 0 if it is undotted. The old value is the note in the current tempo that you intend to hold constant; the new value is what that note becomes on the other side of the pivot.
What it does not settle
Whether a modulation works is a question about the arrangement, not the arithmetic. A ratio the ear cannot follow will sound like a mistake however correctly it is calculated, and a pivot the drums do not spell out will be heard as a stumble. The tool gives you the destination tempo; whether the band lands on it is a matter of rehearsal.
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