How to work out delay times from tempo
Divide 60,000 by the tempo and you have the length of a quarter note in milliseconds. At 120 BPM that is 500ms, so an eighth note is 250ms and a sixteenth is 125ms. Every other value in the calculator is a multiple of that one number.
Dotted values are one and a half times the straight note and triplets are two thirds of it. A dotted eighth at 120 BPM is 375ms, which is the delay that puts its repeats in the gaps of a straight sixteenth figure rather than doubling every note. The creative delay guide covers where each feel works.
Switch the table to hertz to sync an LFO, a tremolo or an auto-panner. The rate in Hz is 1,000 divided by the note length in milliseconds, so a quarter note at 120 BPM is 2Hz.
Tempo-synced reverb: pre-delay and decay
Pre-delay is the gap between the dry note and the start of the reverb, and it does most of the work of placing an instrument front to back. Our reverb guide for cinematic mixing starts close instruments at 30 to 40ms, the middle of the stage at 15 to 20ms and distant sections at 0 to 8ms. The calculator tells you which synced value lands in which range at your tempo.
Long pre-delay fights fast writing. At 120 BPM a sixteenth is 125ms, and pre-delay much above 60ms starts to read as a separate slap against a fast ostinato, so shorten it as the tempo rises.
To make the tail end on the beat, choose the note value it should die on and subtract the pre-delay. That is the decay figure in the table. Treat it as a starting point, because a plugin's decay control usually measures the time to fall by 60dB, and the audible end of a tail in a dense mix comes earlier.
Cue length in bars, seconds and timecode
A bar lasts the number of beats times the length of one beat, and the beat is the bottom number of the time signature. In 6/8 at 120 BPM (quarter-note tempo, as every DAW counts it) each eighth is 250ms, so a bar is 1.5 seconds.
Type a duration under "Fit to a duration" to get the number of bars at your tempo, and the tempo that makes a whole number of bars fit exactly. That is the quickest way to land a 30 second spot or a sting on a cut. The spotting session guide covers how those hit points are agreed in the first place.
Timecode and frame rates
Timecode labels each frame as hours, minutes, seconds and frames. At 24, 25 and 30 fps the label and the clock agree. At 23.976 and 29.97 fps the picture runs 0.1% slower than its labels, so an hour of non-drop timecode at 29.97 lasts 3,603.6 seconds of real time.
Drop-frame timecode fixes that by skipping two frame numbers (four at 59.94) at the start of every minute except every tenth. No picture is lost. Drop-frame timecode is written with a semicolon before the frames, and the calculator follows that convention.
Quarter note lengths at common tempos
| BPM | Quarter (ms) | Eighth (ms) | Dotted eighth (ms) | Sixteenth (ms) |
|---|---|---|---|---|
| 60 | 1000 | 500 | 750 | 250 |
| 70 | 857.14 | 428.57 | 642.86 | 214.29 |
| 72 | 833.33 | 416.67 | 625 | 208.33 |
| 80 | 750 | 375 | 562.5 | 187.5 |
| 85 | 705.88 | 352.94 | 529.41 | 176.47 |
| 90 | 666.67 | 333.33 | 500 | 166.67 |
| 96 | 625 | 312.5 | 468.75 | 156.25 |
| 100 | 600 | 300 | 450 | 150 |
| 108 | 555.56 | 277.78 | 416.67 | 138.89 |
| 110 | 545.45 | 272.73 | 409.09 | 136.36 |
| 120 | 500 | 250 | 375 | 125 |
| 128 | 468.75 | 234.38 | 351.56 | 117.19 |
| 132 | 454.55 | 227.27 | 340.91 | 113.64 |
| 140 | 428.57 | 214.29 | 321.43 | 107.14 |
| 150 | 400 | 200 | 300 | 100 |
| 160 | 375 | 187.5 | 281.25 | 93.75 |
| 174 | 344.83 | 172.41 | 258.62 | 86.21 |
| 180 | 333.33 | 166.67 | 250 | 83.33 |
Looking for a delay with character rather than a number? The tape delay roundup compares the ones film composers reach for.