Tap it
Tap along to the kick for sixteen beats or more and most tap-tempo tools give you a number within a BPM or two. It's fine for a rough idea, and wrong by just enough to drift out of time over a long mix.
Count it
For a loop of known length: bars × 4 × 60 ÷ seconds. A 4-bar loop of 7.5 seconds is 4 × 4 × 60 ÷ 7.5 = 128 BPM. Songs rarely start exactly on a downbeat or end exactly on a bar line, so this works on loops, not on finished tracks.
Measure it
Drop the file on DropWave and read the tempo to two decimal places, with the beat grid drawn on the waveform and the bars marked. Our own 01 Low Orbit reads 140.00 BPM and 05 Riverlight 87.00 BPM, both with High confidence.
Why the decimals: a track that really runs at 127.5 BPM but is labelled 128 drifts a sixteenth note away from a true 128 in 30 seconds. And the more of the song there is, the surer the reading: the first 30 seconds of Riverlight alone read 86.94.
Half, as detected, or double
Riverlight at 87 BPM could just as well be called 174: the same beat, counted twice as fast, the way a drum & bass DJ would hear it. Both are right. Which one you want depends on what you're matching it to.
- DropWave reads between 78 and 152 BPM by default and names the half or double reading as the runner-up when it fits too.
- One click on Half or Double changes it for that track.
- For a genre that lives outside that range, set another range in Settings once.
Check it by ear
Press Click on beats and a click plays on the detected beats. If it stays on the kick from the first bar to the last, the grid is right. If it drifts, the song changes tempo.
When the tempo moves
Live drummers, older records and some edits don't hold one tempo. DropWave shows every stretch that changes tempo with its own BPM and beat grid, instead of one average that fits no part of the song.