Delay and Reverb Time Calculator
Convert a tempo into delay times and reverb decay for every note value.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Delay time follows the selected note value at the entered tempo. Pre-delay and reverb decay are illustrative starting points: pre-delay is set to 20% of delay time, while decay uses a simple room preset adjusted by feedback. Adjust by ear and to the track.
Worked example
calculated with the default values below
Tempo 120 BPM · Note value Dotted quarter · Feedback 30 % · Reverb size Hall Delay time 750.00 ms · Delay time 0.7500 s · Suggested pre-delay (20% heuristic) 150.0 ms · Suggested reverb decay 3.51 s · Feedback 30 % · Delay note value Dotted quarter · Audible repeats 2.5
General background references
Disclaimer
These calculators give general estimates. Sizing, pricing, availability and standards vary by brand, retailer and country, so treat the output as a starting point and confirm it against the seller's or authority's own figures.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
t = (60000 ÷ BPM) × 4v; N = 0 (f = 0), ln(0.05) ÷ ln(f) (f > 0)
- BPM
- Tempo
- v
- Note value
- t
- Delay time (ms)
- f
- Feedback fraction
- N
- Repeats before fade
Pre-delay = 0.2 × delay time (heuristic); decay = room preset × [1 + (1 − feedback fraction)/2]. Both are illustrative starting points.
Frequently asked questions
How long is a dotted eighth at 120 BPM?
A quarter-note beat lasts 500 ms at 120 BPM. A dotted eighth is 3/4 of that beat, so the delay is 375 ms. Reverb decay is a separate approximate room preset.