Delay Feedback Decay Calculator
How many repeats remain at or above a selected level, and when does the next one fall below it?
Method, formula and assumptions
Each additional repeat loses -20 log10(feedback fraction) dB. Floor(threshold drop / repeat loss) counts additional repeats still at or above the threshold. Time is measured from the first repeat.
Input definitions and supported units
- Amplitude retained per repeat (%): Measured or assumed numerical value, from 0.01 to 99.99; must be positive.
- Repeat spacing (ms): Measured or assumed numerical value, from 0.01 to 10000; must be positive.
- Threshold drop below first repeat (dB): Measured or assumed numerical value, from 0 to 200; zero is supported where the stated method permits it.
Worked example with answer
50% amplitude feedback loses 6.0206 dB per repeat. At an 18 dB drop threshold, two additional repeats qualify; the next is below threshold 750 ms after the first with 250 ms spacing.
How to use the results
The first repeat is the reference at time zero, not the dry sound. A threshold of zero permits no additional repeats at or above that reference.
Results retain full precision internally and display up to four decimal places. Very small nonzero results use scientific notation rather than appearing as zero. Check the labels before comparing values across units.
Limitations and references
Ignores filters, saturation, modulation and noise. Feedback must stay strictly between zero and 100%; this is a fixed-amplitude geometric decay.
The method is a self-contained arithmetic, geometric or explicitly stated mathematical model. There are no imported tariffs, empirical presets or equipment specifications; measured values and allowances must come from your own process.
Related planning tools
Creator & reviewers
Creator persona
- Casey RowanUnits, conversions & measurement
Reviewer personas
- Devon ShawFormula & assumptions review
- Sage MitchellClarity & usability review