Tempo-Synced Delay, Pre-Delay & Reverb Time Calculator

How it works

Quarter note (ms) = 60,000 ÷ BPM; dotted = × 1.5, triplet = × 2/3; reverb decay for N bars ≈ N × bar length − pre-delay; LFO Hz = 1,000 ÷ note length (ms)

Effects that repeat or breathe in time with the music sound tighter than ones set by ear alone, and the whole family derives from one number: 60,000 divided by the tempo is the quarter note in milliseconds. Dotted and triplet values give the classic rhythmic delays — the dotted eighth is the sound of countless guitar and synth lines — and dividing further gives pre-delays short enough to separate a vocal from its reverb without a perceptible echo. Setting a reverb’s decay so the tail dies as the next bar starts, or a compressor’s release so it recovers before the next beat, keeps the groove clean; LFO rates for tremolo, filters and sidechain-style pumping are just the reciprocal of a note length. These are starting points that get nudged by ear.

Worked example

At 120 BPM a quarter note is 500 ms, a dotted eighth 375 ms and a sixteenth 125 ms. A one-bar reverb (2,000 ms) with a 1/64-note pre-delay of 31 ms wants a decay around 1,969 ms; a compressor might start at a 31 ms attack and a 500 ms release, and a bar-long sidechain LFO runs at 0.5 Hz.

Frequently asked questions